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1

Vacuum arc recovery phenomena  

Microsoft Academic Search

The present experimental and theoretical study has been designed to uncover the mechanism underlying the rapid recovery of electrical strength of a short vacuum gap after arcing. In the experiment the contacts were of gas-free silver and the contact area and gap length were varied. Recovery strength was measured following the forced extinction of a 250 amp arc in 0.5

J. A. Rich; G. A. Farrall

1964-01-01

2

Review of Anode Phenomena in Vacuum Arcs.  

National Technical Information Service (NTIS)

This paper reviews anode phenomena in vacuum arcs. It discusses arc modes at the anode, anode temperature measurements, anode ions, transitions of the arc into various modes (principally the anode spot mode), and theoretical explanations of anode phenomen...

H. C. Miller

1984-01-01

3

Review of anode phenomena in vacuum arcs  

SciTech Connect

This paper reviews anode phenomena in vacuum arcs. It discusses arc modes at the anode, anode temperature measurements, anode ions, transitions of the arc into various modes (principally the anode spot mode), and theoretical explanations of anode phenomena. A vacuum arc can exhibit five anode discharge modes: (1) a low current mode in which the anode is basically passive, acting only as a collector of particles emitted from the cathode; (2) a second low current mode that can occur if the electrode material is readily sputtered (a flux of sputtered atoms will be emitted by the anode); (3) a footpoint mode, characterized by the appearance of one or more luminous spots on the anode (footpoints are much cooler than the true anode spots present in the last two modes); (4) an anode spot mode in which one large or several small anode spots are present (such spots are very luminous, have a temperature near the atmospheric boiling point of the anode material, and are a copious source of vapor and ions); and (5) an intense arc mode where an anode spot is present, but accompanied by severe cathode erosion. The arc voltage is relatively low and quiet in the two low current modes and the intense arc mode. It is usually high and noisy in the footpoint mode, and it can be either in the anode spot mode. Anode erosion is low, indeed negative, in the two low current modes, and it is low to moderate in the footpoint mode. Severe anode erosion occurs in both the anode spot and intense arc modes.

Miller, H.C.

1984-06-04

4

High-current vacuum arc: The relationship between anode phenomena and the average opening velocity of vacuum interrupter  

Microsoft Academic Search

In order to understand the influence of the average opening velocity on the high-current vacuum arc anode phenomena, a high-speed photography was used to observe anode phenomena of vacuum arc discharge in vacuum interrupters. The contact diameters used in the vacuum interrupters were 12 mm and 25 mm, respectively. The contact materials included Cu, CuCr25, and CuCr50. The arc current

Guowei Kong; Zhiyuan Liu; Dong Wang; Mingzhe Rong

2010-01-01

5

Change in optical properties of CuI crystals upon annealing in vacuum  

NASA Astrophysics Data System (ADS)

Copper iodide crystals with different compositions of crystalline defects have been prepared using the developed technique for their synthesis and annealing in vacuum with subsequent quenching. The spectra of absorption, excitation, and photoluminescence of the CuI crystals, as well as their electrical resistance, have been analyzed. It has been found that the optical properties of the crystals change as a result of the increase in the number of point defects and inclusions of the second phase in the samples after high-temperature annealings (as compared to low-temperature annealings). This effect is caused by the deviation of the composition of the material from stoichiometry during annealing in vacuum.

Gruzintsev, A. N.; Zagorodnev, V. N.

2012-01-01

6

Low temperature vacuum annealing study of (Co/Pd)n magnetic multilayers  

NASA Astrophysics Data System (ADS)

The correlation between the magnetic properties and the microstructural and chemical composition modifications of Co/Pd magnetic multilayers upon annealing in ultrahigh vacuum at 250 C is presented. Magnetic characterization using magnetic sample magnetometer shows the vertical magnetic anisotropy increase and the switching field distribution decrease in the annealed samples. The larger values of magnetic anisotropy in the annealed samples are further shown using the magnetic force microscopy of the ac demagnetized states in the Co/Pd multilayer films. X-ray diffraction rocking curves show an improvement in the texture and the initial magnetization curve slopes indicate the decreases in defect densities. Overall, vacuum annealing under optimal conditions improves the magnetic properties of Co/Pd multilayers for applications in ultrahigh density magnetic recording.

E, Chunsheng; Rantschler, James; Zhang, Shishan; Khizroev, Sakhrat; Lee, T. Randall; Litvinov, Dmitri

2008-04-01

7

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

8

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

NASA Astrophysics Data System (ADS)

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; Ni, Zhenhua; Li, Aizhi; Zafar, Zainab; Zhang, Yan; Ni, Zhonghua; Qu, Shiliang; Qiu, Teng; Yu, Ting; Xiang Shen, Ze

2011-12-01

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

Investigation on Novel Characterization Parameters of Surface Flashover Phenomena in Vacuum  

Microsoft Academic Search

Surface flashover in vacuum is a kind of complicated surface and interface phenomena, which seriously hamper the overall performance of many electrical and electronic devices. It has been realized that surface condition of a solid material strongly affects its flashover phenomena under high electric field. The artificial doping ingredients could change the energy distribution and the density of electron and

Guan-Jun Zhang; Wen-Bin Zhao; Nan Zheng; Zhang Yan

2006-01-01

11

An opening displacement characteristic determined by high-current anode phenomena of vacuum interrupter  

Microsoft Academic Search

A vacuum interrupter reaches its interruption limit once high-current anode phenomena occur. It is well-known that contact diameter, contact material, and magnetic field have a significant influence on high-current anode phenomena formation. However, an opening displacement characteristic of movable contact is another contribution for an anode spot formation. The objective of this paper is to propose an opening displacement characteristic

Liqiong Sun; Li Yu; Zhiyuan Liu; Jianhua Wang; Yingsan Geng

2011-01-01

12

99.9% purity multi-walled carbon nanotubes by vacuum high-temperature annealing  

Microsoft Academic Search

Ultrahigh purity multi-walled carbon nanotubes (MWNTs) were obtained, which were produced by a catalytic chemical vapor deposition method and subsequently annealed at vacuum pressures between 10?3 and 10 Pa and temperatures between 1500 and 2150C. Acid treatments were made for comparison. Scanning electron microscopy, transmission electron microscopy and energy dispersive spectra were used to characterize the specimens. Purities were characterized

Wei Huang; Yao Wang; Guohua Luo; Fei Wei

2003-01-01

13

Recovery of surface conductivity of H-terminated diamond after thermal annealing in vacuum  

NASA Astrophysics Data System (ADS)

A unique feature of diamond among other semiconductors is the formation of a high conductive p-type layer which is usually obtained after hydrogen-termination of the surface. It is generally accepted that the appearance of surface conductivity (SC) requires the presence of atmospheric adsorbates. We present a combination of conductivity and spectroscopic measurements dealing with the loss and the formation of SC as a function of annealing in vacuum (temperatures 60 900 C) and exposure to different atmospheres. For temperatures below 190 C in vacuum the SC decreases by more than five orders of magnitude and comes back to its initial value when the sample is exposed to air. After annealing between 250 and 700 C exposure to normal atmospheric conditions is no longer sufficient to recover SC, although the H termination is preserved. In this state the SC is fully restored upon air exposure after the surface has been exposed to ozone or oxygen radicals. We propose a model where oxygen-related sites are catalytically involved in the transfer-doping mechanism such that the rate of electron transfer from the diamond into solvated adsorbates is enhanced.

Riedel, M.; Ristein, J.; Ley, L.

2004-03-01

14

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

15

Effects of rapid thermal annealing in vacuum on electrical properties of thin Ta 2O 5Si structures  

Microsoft Academic Search

The effect of rapid thermal annealing (RTA) in vacuum (1273K) on the properties of thin thermal Ta2O5 films in dependence on the oxidation temperature (673873K) has been studied. It is established that the electrical and dielectric properties of the annealed layers are rather strong function of the oxidation temperature than of the film thickness. RTA reduces the leakage current of

D. Spassov; E. Atanassova; G. Beshkov

2000-01-01

16

Electrical properties of vacuum annealed La2O3 thin films grown by E-beam evaporation  

Microsoft Academic Search

In this article, the conduction mechanisms of metal-oxide-semiconductor with vacuum annealed Lanthana (La2O3) oxide film are investigated. Lanthana films with thicknesses of 3.5, 4.7, and 11nm were deposited by E-beam evaporation on n-Si (100), and annealed at various temperatures (300500C) in ultra-high vacuum (10?1010?9Torr) for 90min. From the measurement of spectroscopic ellipsometry, it is found that film thickness is increased

Yongshik Kim; Kunihiro Miyauchi; Shun'ichiro Ohmi; Kazuo Tsutsui; Hiroshi Iwai

2005-01-01

17

Diameter dependence of oxidative stability in multiwalled carbon nanotubes: Role of defects and effect of vacuum annealing  

Microsoft Academic Search

While the oxidative stability of single walled carbon nanotubes has been studied extensively, very little is known about the diameter dependence of oxidative stability in multiwalled carbon nanotubes (MWNTs) and the effect of vacuum annealing on such stability. We have investigated six sets of samples with different diameters in the range of 5-100 nm systematically by thermogravimetric analysis (TGA) before

Dilip K. Singh; Parameswar K. Iyer; P. K. Giri

2010-01-01

18

Diameter dependence of oxidative stability in multiwalled carbon nanotubes: Role of defects and effect of vacuum annealing  

Microsoft Academic Search

While the oxidative stability of single walled carbon nanotubes has been studied extensively, very little is known about the diameter dependence of oxidative stability in multiwalled carbon nanotubes (MWNTs) and the effect of vacuum annealing on such stability. We have investigated six sets of samples with different diameters in the range of 5100 nm systematically by thermogravimetric analysis (TGA) before

Dilip K. Singh; Parameswar K. Iyer; P. K. Giri

2010-01-01

19

Diameter dependence of oxidative stability in multiwalled carbon nanotubes: Role of defects and effect of vacuum annealing  

NASA Astrophysics Data System (ADS)

While the oxidative stability of single walled carbon nanotubes has been studied extensively, very little is known about the diameter dependence of oxidative stability in multiwalled carbon nanotubes (MWNTs) and the effect of vacuum annealing on such stability. We have investigated six sets of samples with different diameters in the range of 5-100 nm systematically by thermogravimetric analysis (TGA) before and after vacuum annealing. High resolution transmission electron microscopy studies provide evidence for structural defects in the nanotube walls. Further, it reveals that with increasing diameter, interlayer d-spacing between concentric tubes decreases. Experimental TGA profile is found to constitute multiple components of oxidation as revealed from reverse Sigmoidal fitting. Analysis of the TGA profile shows that the oxidation temperature follows an exponential recovery function with increasing diameter, while width of the differentiated TGA spectra decreases. It is shown that oxidative stability of lower diameter MWNTs are primarily controlled by lattice strain, while that of large diameter MWNTs is decided by the defects in the nanotube wall. High vacuum annealing studies in the temperature range 300-1000 C show major improvement in the structure and oxidative stability for MWNTs annealed at 500 C. Results are compared with those of the single walled nanotubes. The observed diameter dependence is explained on the basis of strain in the nanotube lattice and defects in the nanotube walls.

Singh, Dilip K.; Iyer, Parameswar K.; Giri, P. K.

2010-10-01

20

High-Current Vacuum Arc: The Relationship Between Anode Phenomena and the Average Opening Velocity of Vacuum Interrupters  

Microsoft Academic Search

In order to understand the influence of the average opening velocity on the high-current vacuum arc anode phenom- ena, high-speed photography was used to observe the anode phe- nomena of the vacuum arc discharge in vacuum interrupters. The contact diameters used in the vacuum interrupters were 12 and 25 mm, respectively. The contact materials included Cu, CuCr25, and CuCr50. The

Guowei Kong; Zhiyuan Liu; Dong Wang; Mingzhe Rong

2011-01-01

21

Preflashover and flashover phenomena of silicon-vacuum system under pulsed excitation  

NASA Astrophysics Data System (ADS)

Rectangular n+nn+-type silicon blocks with different surface treatments, i.e., one surface is chemically etched and the other is unetched, were used to investigate the characteristics of preflashover and flashover of semiconductor under a high voltage pulse in a vacuum. The metallic contacts were employed to keep a fine contact between the sample and the electrode. For unetched samples, the preflashover current obeyed Ohm's law, and for etched samples, it was dominated by the space-charge limited current. After flashover shots, two kinds of silicon samples showed quite distinct tracks. It is considered that all the phenomena are attributed to the different density and distribution of surface states for two kinds of samples. The developing process of surface flashover across a semiconductor could be explained as the current filamentation which is induced by thermal effects. It is suggested that the flashover occurs in the interface layer of silicon butted to electrodes, and in the lateral layer of silicon near the vacuum ambient with a depth of ~2 ?m.

Zhang, Guan-Jun; Yan, Z.; Liu, Y. S.; Yasuoka, K.; Ishii, S.

2002-05-01

22

Annealing effects of tantalum films on Si and SiO{sub 2}/Si substrates in various vacuums  

SciTech Connect

The annealing effects of 550 nm thick {beta}-Ta films sputtered on Si and SiO{sub 2} substrates have been investigated under various vacuum conditions. Phase transformation from the tetragonal {beta}-Ta into body-centered-cubic {alpha}-Ta of much higher conductivity occurred at annealing temperatures lower than 500{degree}C and 80% of {beta}-Ta transformed into {alpha}-Ta after annealing at 600{degree}C for Ta on a Si substrate. For Ta on a SiO{sub 2} substrate, no phase transformation was observed at 500{degree}C annealing, and only 20% of {beta}-Ta transformed into {alpha}-Ta at 600{degree}C. Oxygen diffusion into the Ta film at the interface of Ta/SiO{sub 2} could hinder {beta}-Ta to {alpha}-Ta transformation. Both Ta on Si and Ta on SiO{sub 2} samples have smooth surfaces after annealing in 2{times}10{sup {minus}5}Torr. After annealing in a vacuum lower than 2{times}10{sup {minus}4}Torr, surface oxidation of the Ta thin films was detected. The increase of oxygen content in the Ta films caused higher compressive stress, and resulted in the film peeling in a serpentine pattern during annealing at 500{degree}C in 2{times}10{sup {minus}2}Torr for Ta on a SiO{sub 2} substrate. The Ta films cracked and detached from the SiO{sub 2} substrate after being annealed at 750{degree}C in 2{times}10{sup {minus}2}Torr. In contrast, no crack was found in Ta on Si, probably because of the relief of film stress due to more {beta}-Ta being transformed into {alpha}-Ta during annealing. The residual oxygen and moisture in low vacuum may build up stress in Ta thin films during thermal processes, which can cause major reliability problems in electronic and other applications. {copyright} 2001 American Institute of Physics.

Liu, Ling; Wang, Yue; Gong, Hao

2001-07-01

23

Effect of vacuum annealing cleaning on electrical characteristics of GaAs\\/1-x\\/P\\/x\\/Mo Schottky diodes  

Microsoft Academic Search

A vacuum annealing procedure for surface cleaning prior to barrier metal evaporation is proposed. The reported method is suitable for III-V compounds and has been checked for GaAs\\/1-x\\/P\\/x\\/-Mo Schottky diodes. Electrical characteristics of the junctions seem to be best at around 550 C, but for higher temperatures the electrical characteristics degenerate, indicating the incorporation of a surface layer with a

E. Calleja; J. Piqueras

1981-01-01

24

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

25

Annealing of amorphous Ru-Si-O and Ir-Si-O films in vacuum or dry oxygen  

NASA Astrophysics Data System (ADS)

Films about 200 nm thick of composition Ru17Si16O67 (~50% RuO2+50% SiO2) and Ir18Si15O67 (~55% IrO2+45% SiO2) deposited on oxidized silicon wafers by reactive magnetron sputtering with an argon-oxygen gas mixture from bielemental targets have been annealed in vacuum or in oxygen. As deposited, the films are amorphous by x-ray diffraction as well as by transmission electron microscopy. Upon annealing in vacuum, grains of metal dioxide nucleate and grow in both films, as x-ray diffraction scans reveal. These grains dissociate into metal grains and oxygen. The process is well underway in the Ir18Si15O67 film at 700 C after 12 h while it has barely begun at 800 C after 5 h in the Ru17Si16O67 film. 2.0 MeV 4He++ backscattering spectra establish that oxygen in the amount initially bonded to the metal escapes out of the film that thins down as a result, but remains dense nonetheless. The results are qualitatively consistent with a diffusion-controlled outward flow of oxygen in a heterogeneous medium of metal dioxide and silica. Thermodynamic calculations for the two systems show that oxygen has the highest partial pressure of all gaseous species in both cases, but in the iridium case the oxygen partial pressure exceeds that in the ruthenium case by at least 100-fold. The dissimilar behavior under annealing in vacuum evidently has a thermodynamic component at its origin. When heated in oxygen, a Ru17Si16O67 film is quite unstable, and increasingly so with rising oxygen pressure. The iridium-based films remain essentially unchanged upon annealing at 700 C for 5 min under 760 Torr of dry oxygen. This dissimilarity between the Ru-Si-O and Ir-Si-O films is rooted in the existence of the volatile RuO4 phase that has no analogue species in the iridium-oxygen system. The high stability of amorphous Ir18Si15O67 films under thermal annealing in an oxidizing ambient is significant for applications where electrically conducting films are required that can withstand such exposures essentially unchanged.

Giauque, P. H.; Nicolet, M.-A.

2003-04-01

26

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

27

High-speed motion analysis of surface melting phenomena of high-current vacuum arcs  

Microsoft Academic Search

In order to explore the physical mechanisms limiting the breaking capability of contact materials in vacuum interrupters, experiments have been performed to investigate the plasma- electrode interaction of high-current vacuum arcs in detail, in particular the surface heating effects leading to contact melting, erosion, and droplet formation. The arcs are drawn in a synthetic test circuit between industrially designed Cu-Cr

N. Wenzel; W. Wietzorek; W. Hartmann; A. Lawall; R. Renz

2008-01-01

28

Thermal and non-thermal surface phenomena and their impact on vacuum  

Microsoft Academic Search

A review is presented on the role that thermal and supra-thermal phenomena play on the outgassing behaviour of technical materials. Some of the new findings that shed light into the underlying mechanisms responsible for outgassing are shown. The role of surface modification by physical and chemical means is analysed. The progress in the field in relation with the operation of

F. L Tabars

2002-01-01

29

Positron annihilation induced Auger electron spectroscopic study of the changes in the top layers of electrodeposited Cu2O surfaces resulting from vacuum annealing  

NASA Astrophysics Data System (ADS)

Positron Annihilation induced Auger electron Spectroscopy (PAES) and electron stimulated Auger Spectroscopy (EAES) were used to measure changes in the surface of electrodeposited Cu2O resulting from vacuum annealing. The PAES measurements show a very large increase in the intensity of the Cu MVV Auger peak after annealing at 535 K. Similar but significantly smaller changes were observed in the EAES spectra consistent with the fact that PAES is primarily sensitive to the top-most atomic layer due to the fact that the positrons are trapped just outside the surface prior to annihilation while EAES samples several atomic layers. The PAES and EAES data indicate that vacuum annealing of Cu2O results in a surface with a high concentration of Cu in the top-most atomic layer. Research supported by the Welch Foundation Y-1100 and NSF DMR 98-12628.

Nadesalingam, M.; Zhu, J.; Fazleev, N.; Mukherjee, S.; de Tacconi, N. R.; Somasundaram, S.; Chenthamarakshan, C. R.; Rajeshwar, K.; Weiss, A. H.

2006-03-01

30

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

31

Effect of non-vacuum thermal annealing on high indium content InGaN films deposited by pulsed laser deposition.  

PubMed

InGaN films with 33% and 60% indium contents were deposited by pulsed laser deposition (PLD) at a low growth temperature of 300 C. The films were then annealed at 500-800 C in the non-vacuum furnace for 15 min with an addition of N(2) atmosphere. X-ray diffraction results indicate that the indium contents in these two films were raised to 41% and 63%, respectively, after annealing in furnace. In(2)O(3) phase was formed on InGaN surface during the annealing process, which can be clearly observed by the measurements of auger electron spectroscopy, transmission electron microscopy and x-ray photoelectron spectroscopy. Due to the obstruction of indium out-diffusion by forming In(2)O(3) on surface, it leads to the efficient increment in indium content of InGaN layer. In addition, the surface roughness was greatly improved by removing In(2)O(3) with the etching treatment in HCl solution. Micro-photoluminescence measurement was performed to analyze the emission property of InGaN layer. For the as-grown InGaN with 33% indium content, the emission wavelength was gradually shifted from 552 to 618 nm with increasing the annealing temperature to 800 C. It reveals the InGaN films have high potential in optoelectronic applications. PMID:23546117

Wang, Tzu-Yu; Ou, Sin-Liang; Shen, Kun-Ching; Wuu, Dong-Sing

2013-03-25

32

Applications of canonical transformations and nontrivial vacuum solutions to flavor mixing and critical phenomena in quantum field theory  

NASA Astrophysics Data System (ADS)

In this dissertation we consider two recent applications of Bogoliubov Transformation to the phenomenology of quantum mixing and the theory of critical phenomena. In recent years quantum mixing got in the focus of the searches for New Physics due to its unparalleled sensitivity to SM parameters and indications of neutrino mixing. It was recently suggested that Bogoliubov Transformation may be important in proper definition of the flavor states that otherwise results in problems in perturbative treatment. As first part of this dissertation we investigate this conjecture and develop a complete formulation of such a mixing field theory involving introduction of general formalism, analysis of space-time conversion and phenomenological implications. As second part of this dissertation we focus our attention on Oscillator Representation Method relevant to the study of degrees-of-freedom rearrangement during phase transitions in which vacuum condensation and mass change are analyzed using Bogoliubov Transformation. Given parallels with the duality between quarks and hadrons as well as constituent and current quarks, this method presents attractive and interesting idea. We review this method and consider its applications to nonlinear sigma model and other models. We also discuss possible schemes for its improvement. We further introduce a novel approach in QFT---method of Symmetric Decomposition Problem. Here, we attempt to substitute variational problem in terms of complicated Fock space with a constrained minimization problem in terms of expectation values of only the relevant operators. Application of this principle to quadratic operators and the exact constraints on their expectation values are discussed along with an example of study of the ground state in a variant of nonlinear sigma model.

Mishchenko, Yuriy

33

Effect of annealing under vacuum and in nitrogen atmosphere on the structure and strength of porous silicon nitride materials  

Microsoft Academic Search

This paper deals with a study of the structure and the temperature dependence of the strength of the porous silicon nitride materials after prolonged holding at high temperatures under vacuum and in a protective atmosphere (nitrogen). Reaction-sintered Si3N 4 having a porosity 0 = 59.3-68.0% was used in this investigation. In order to obtain a porous material, we used 1.0-1.5

V. N. Antsiferov; V. G. Gilev; A. G. Lanin; O. N. Erin; V. N. Turchin; S. V. Leonov

1993-01-01

34

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

35

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

36

Coupling of hydrodynamic mechanism and deformation-relaxation phenomena during vacuum treatments in solid porous food-liquid systems  

Microsoft Academic Search

The aim of this work is to extend the hydrodynamic mechanism (HDM) analysis, initially considered with no occurrence of deformations in the solid matrix, to the case of coupling HDM and deformation-relaxation phenomena (DRP). The mathematical model developed in a previous paper regarding HDM, has been extended, taking into account the possibility of solid matrix deformations because of the expansion

P. Fito; A. Andrs; A. Chiralt; P. Pardo

1996-01-01

37

Tree-like breakdown phenomena of dielectric window under X-band high power microwave in vacuum  

Microsoft Academic Search

Surface breakdown of dielectric window seriously limits the transmission of high power microwave (HPM), which blocks the development of microwave technology. Under Xband HPM with the power level of 1 GW at 9.4 GHz, dielectric breakdown experiments were conducted with several dielectric window materials including polytetrafluoroethylene (PTFE), low-density polyethylene (LDPE), high-density polyethylene (HDPE) and polymethyl methacrylate (PMMA) in vacuum. The

Shi Qiu; Xi-Wei Hao; Guan-Jun Zhang; Guo-Zhi Liu; Qing Hou; Wen-Hua Huang; Zhi-Qiang Zhang; Xiao-Xin Zhu

2010-01-01

38

Postdeposition annealing influence on sputtered indium tin oxide film characteristics  

NASA Astrophysics Data System (ADS)

The influence of postdeposition annealing on sputtered indium tin oxide (ITO) film characteristics were investigated. The annealing experiments were carried out in air or vacuum atmosphere. Both air and vacuum annealing decreased the resistivity up to heat treatment of 200 C. Over 300 C treatment, air annealingincreased resistivity whereas vacuum annealing decreased it. It was clarified that the resistivity depended on the carrier concentration.

Higgins, Masatoshi; Uekusa, Shinichiro; Nakano, Pyotaro; Yokogawa, Kazuhiko

1994-01-01

39

Effect of vacuum annealing on the structure and superconductivity of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} single crystals.  

SciTech Connect

The effect of annealing on the structure and superconductivity of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} has been investigated on high-quality and large single crystals grown by the traveling solvent floating zone technique. Vacuum annealing was carried out on crystals sealed in quartz ampoules under different oxygen pressure ranging from 8 x 10{sup -1} to 5 x 10{sup -4} bar. The as-grown and post-annealed crystals were explored by induction-coupled plasma atomic emission spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM) and magnetization measurements. It was demonstrated that the oxygen homogeneity of the as-grown crystals has a direct influence on the post-annealed samples. The superconducting transition temperature, T{sub c} was found to be affected more strongly by the annealing oxygen partial pressures, p(O{sub 2}), than by the annealing temperature. T{sub c} decreases considerably from 92 to 29 K with decreasing p(O2) from 1 down to 4 x 10{sup -2} bar, however, increases surprisingly to 62 K with further decreasing p(O{sub 2}) to 5 x 10{sup -4} bar. The transitions remain relatively sharp for the samples annealed under p(O{sub 2})=8 x 10{sup 01}-4 x 10{sup 02} bar, with no evidence of significant structural change by powder XRD measurement. XRD studies indicate that the crystals have orthorhombic symmetry. The refinement result for XRD data shows that the c-axis expands, while both a- and b-axis contract slightly with decreasing p(O{sub 2}). The relation between T{sub c} and the c-axis lattice parameter suggests that the change of T{sub c} is correlated with a redistribution of holes between the Bi-O layers and the Cu-O planes. Impurity phases were found to segregate from samples annealed under p(O{sub 2}) < 4 x10{sup -2} bar. The one-dimensional incommensurate superstructure along the b-axis was observed by TEM in the crystal annealed at p(O{sub 2})=1 x 10{sup -3} bar. The lattice strain caused by the high-vacuum annealing possibly affect the Cu-O-Cu angle and lead to an anomalous change in T{sub c}.

Liang, B.; Lin, C. T.; Maljuk, A.; Yan, Y.; Energy Technology; Max-Planck-Inst.

2002-02-01

40

Postdeposition Annealing Influence on Sputtered Indium Tin Oxide Film Characteristics  

NASA Astrophysics Data System (ADS)

The influence of postdeposition annealing on sputtered indium tin oxide (ITO) film characteristics were investigated. The annealing experiments were carried out in air or vacuum atmosphere. Both air and vacuum annealing decreased the resistivity up to heat treatment of 200 C. Over 300 C treatment, air annealing increased resistivity whereas vacuum annealing decreased it. It was clarified that the resistivity depended on the carrier concentration. The lowest resistivity attained was 1.310-4 ?cm, with film deposited on a 250 C heated substrate and annealed in vacuum atmosphere at 300 C. Transmittance was improved in both air and vacuum annealing. In air and vacuum annealing, crystallinity improved with increasing annealing temperature. The surface topography showed no changes with air or vacuum annealing.

Higuchi, Masatoshi; Uekusa, Shinichiro; Nakano, Ryotaro; Yokogawa, Kazuhiko

1994-01-01

41

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

2013-09-04

42

Investigation of the effect of in situ annealing of FePt nanodots under high vacuum on the chemical states of Fe and Pt by x-ray photoelectron spectroscopy  

NASA Astrophysics Data System (ADS)

The chemical states of Fe and Pt in in situ annealed L10 structured FePt nanodots formed by self-assembled nanodot deposition method have been systematically investigated by angle resolved x-ray photoelectron spectroscopy. From the Fe3p and the Pt4f core level x-ray photoelectron (XP) spectra, it is evident that both the Fe and Pt of the nanodots were oxidized in the as-grown state. After the in situ annealing under high vacuum, a peak corresponding to metallic Fe begins to appear, and subsequently the metallic peak fraction increased with the increase in the annealing temperature. In line with this, the peak fraction of the respective oxides is drastically decreased. Irrespective of the annealing temperatures, it is inferred from the intensity of the XP spectrum that the Fe atom of the FePt nanodots is highly prone to oxidation than the Pt atom. Nevertheless, the valence band spectra of the as-grown FePt nanodot film clearly depict the presence of metallic Fe-Pt alloy. We would like to explain the results of the core level and valence band XP spectra as follows: only the peripheral Fe and Pt atoms of the as-formed FePt nanodots are bonded to the oxygen of the cosputtered SiO2 matrix, whereas the metallic core of the as-formed FePt nanodots is always preserved. The very good vacuum ambient during postannealing highly promotes the dissociation of oxygen from the metal oxides via reduction reaction. This results into an increase in the fraction of metallic Fe and Pt at the periphery of FePt nanodots and the formation of high quality SiO2 matrix after annealing. Similar results were also observed for the monatomic W as well as Pt nanodots embedded in SiO2 matrix. Hence, this simple, rather effective method of in situ annealing of metal dots dispersed in an insulating matrix can be readily employed in the fabrication of high-density nanodot memory devices.

Murugesan, M.; Bea, J. C.; Yin, C.-K.; Nohira, H.; Ikenaga, E.; Hattori, T.; Nishijima, M.; Fukushima, T.; Tanaka, T.; Miyao, M.; Koyanagi, M.

2008-10-01

43

The role of dislocations in the formation of mechanical stresses during annealing of gallium arsenide single crystals  

Microsoft Academic Search

The effect of dislocations on the change of mechanical stresses in undoped semi-insulating gallium arsenide single crystals\\u000a has been studied during their annealing in vacuum and in the arsenic atmosphere. The phenomena observed are explained by the\\u000a effect of dislocations playing the role of channels for arsenic diffusion on the concentration of intrinsic point defects\\u000a in the crystal regions surrounding

M. B. Litvinova; S. V. Shutov

2001-01-01

44

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

45

Paranormal phenomena  

Microsoft Academic Search

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.

Alex Gaina

1996-01-01

46

Ultra high vacuum technology  

Microsoft Academic Search

A short introduction for some basic facts and equations. Subsquently, discussion about: Building blocks of an ultrahigh vacuum system - Various types of pumps required to reach uhv and methods to reduce these effects - Outgassing phenomena induced by the presence of a particle beam and the most common methods to reduce these effects It will be given some practical

Oswald Grbner

2001-01-01

47

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

48

Backdraft Phenomena.  

National Technical Information Service (NTIS)

The purpose of this project was to develop a fundamental physical understanding of backdraft phenomena. The research was divided into three phases: exploratory simulations, gravity current modeling, and quantitative backdraft experiments. The primary goal...

C. M. Fleischmann

1994-01-01

49

Effects of defects generated in ALD TiO 2 films on electrical properties and interfacial reaction in TiO 2 \\/SiO 2 \\/Si system upon annealing in vacuum  

Microsoft Academic Search

Thin TiO2 layers grown at 130C on SiO2-coated Si substrates by atomic layer deposition (ALD) using TTIP and H2O as precursors were annealed, and the effects of the annealing temperature on the resulting electrical properties of TiO2 and the interface properties between a Pt electrode and TiO2 were examined using transmission line model (TLM) structures. The as-deposited TiO2 thin film

Sanghee Won; Seunghee Go; Wonhee Lee; Kyunghoon Jeong; Hyunsuk Jung; Chongmu Lee; Eungu Lee; Jaegab Lee

2008-01-01

50

Breakdown phenomena in high power klystrons  

Microsoft Academic Search

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

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

1988-01-01

51

Investigation of the effect of in situ annealing of FePt nanodots under high vacuum on the chemical states of Fe and Pt by x-ray photoelectron spectroscopy  

Microsoft Academic Search

The chemical states of Fe and Pt in in situ annealed L10 structured FePt nanodots formed by self-assembled nanodot deposition method have been systematically investigated by angle resolved x-ray photoelectron spectroscopy. From the Fe3p and the Pt4f core level x-ray photoelectron (XP) spectra, it is evident that both the Fe and Pt of the nanodots were oxidized in the as-grown

M. Murugesan; J. C. Bea; C.-K. Yin; H. Nohira; E. Ikenaga; T. Hattori; M. Nishijima; T. Fukushima; T. Tanaka; M. Miyao; M. Koyanagi

2008-01-01

52

VACUUM TRAP  

DOEpatents

An improved adsorption vacuum trap for use in vacuum systems was designed. The distinguishing feature is the placement of a plurality of torsionally deformed metallic fins within a vacuum jacket extending from the walls to the central axis so that substantially all gas molecules pass through the jacket will impinge upon the fin surfaces. T fins are heated by direct metallic conduction, thereby ol taining a uniform temperature at the adeorbing surfaces so that essentially all of the condensible impurities from the evacuating gas are removed from the vacuum system.

Gordon, H.S.

1959-09-15

53

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

54

Post-annealing effects on magnetic properties and microstructure of CoCrPtN\\/Ti\\/C perpendicular recording media  

Microsoft Academic Search

CoCrPtN\\/Ti\\/C thin films were prepared by adding N2 into the sputtering chamber during the deposition of magnetic layer. Annealing treatments, including vacuum annealing and N2 flow atmosphere annealing were performed for CoCrPtN\\/Ti\\/C thin films. Annealed CoCrPtN\\/Ti\\/C thin films show better magnetic properties than the conventional CoCrPt\\/Ti\\/C thin films do, especially the vacuum annealed one. Nitrogen atoms incorporated in annealed CoCrPtN\\/Ti\\/C

X. M. Cheng; Z. Y. Li; X. F. Yang; Q. Li; Z. Li; F. Jin; G. Q. Lin

2006-01-01

55

Athermal Annealing of Silicon  

Microsoft Academic Search

Current semiconductor annealing methods are based on thermal processes which are accompanied by diffusion that degrades the definition of device features or causes other problems. This will be a serious obstacle for the production of next-generation ultra-high density, low power semiconductor devices. Experiments underway at NRL utilize a new annealing method which is much faster than thermal annealing and does

R. P. Fischer; J. Grun; A. Ting; C. Felix; M. Peckerar; M. Fatemi; C. K. Manka

1999-01-01

56

Breakdown phenomena in high-power klystrons  

Microsoft Academic Search

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. In addition, a renewed interest in breakdown phenomena for ns pulse, MV\\/cm fields has been sparked by recent R and D work in the area of GW rf sources. The most important

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

1989-01-01

57

Effect of annealing conditions on structural and magnetic properties of laser ablated copper ferrite thin films  

NASA Astrophysics Data System (ADS)

The effect of annealing conditions on structural and magnetic properties of copper ferrite thin films on (100) Si substrates was examined in detail. After deposition, the ferrite thin films were post-annealed in vacuum and in oxygen atmosphere for several hours. It is found that the crystal structure of CuFe2O4 thin films changed drastically depending on different heating process. A maximum magnetization was achieved in the film that was vacuum annealed and it decreased remarkably after oxygen annealing.

Raghavender, A. T.; Hoa Hong, Nguyen; Park, Chulkwon; Jung, Myung-Hwa; Lee, Kyu Joon; Lee, Daesu

2012-05-01

58

Understanding the thermal annealing process on metallic thin films  

NASA Astrophysics Data System (ADS)

Thermal annealing is an usual process used for intrinsic stress liberation, structural improving, and surface roughness control in materials. In a qualitative way, annealing modifies the surface morphology of materials with temperature and time. In this work, a methodology to explain the surface modification of thin films when they are submitted to an annealing process is discussed. Two thermally evaporated Au films with 200 nm-thicknesses were post-annealed in a vacuum chamber at 100 C with an argon atmosphere, and annealing times from 0 to 1000 minutes. Each Au film grown at different rate deposition was cyclical annealed and imaged under different annealing times. Data obtained from high quality AFM images after different annealing times of Au samples were used to calculate surface parameters such as roughness, grain size, and slope at the border, also the respective exponents as a function of the annealing time. The experimental results allow understanding the temporal evolution of the annealing process, as a rearrangement of the surface protrusions.

Alonzo-Medina, G. M.; Gonzlez-Gonzlez, A.; Sacedn, J. L.; Oliva, A. I.

2013-06-01

59

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

60

Vacuum Technique  

Microsoft Academic Search

Let me say from the beginning that it was a pleasure to peruse this book and I recommend it to researchers and engineers from the field of Cryogenics, both as an introduction and for use in day-to-day work.There are many areas in pure science in which vacuum conditions are required for conducting an experiment, such as solid state physics at

L N Rozanov

2002-01-01

61

Effects of Oxygen Annealing in Fe(Te,Se) Single Crystals  

NASA Astrophysics Data System (ADS)

Iron-chalcogenide superconductor Fe(Te,Se) has the simplest structure among all iron-based superconductors. Yet, its superconducting properties except for Tc are not very much reproducible. This is partly due to the fact that the as-grown crystals of Fe(Te,Se) is not superconducting, and post-annealing is important to induce superconductivity. We found that the annealing in a controlled oxygen atmosphere is very important to induce superconductivity in this system. Upon annealing in oxygen atmosphere, the content of excess iron in the crystal decreases. We will demonstrate the dynamics of the oxygen annealing process by changing the annealing time and temperature. We also compare the effect of different annealing conditions, such as vacuum annealing, with that of oxygen annealing. Finally, physical properties of well-characterized Fe(Te,Se) crystals are discussed together with the vortex physics in this system.

Tamegai, Tsuyoshi; Sun, Yue; Taen, Toshihiro; Tsuchiya, Yuji; Shi, Zhixiang

2013-03-01

62

O 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

63

The dependence of normal and abnormal grain growth in silver on annealing temperature and atmosphere  

Microsoft Academic Search

When polycrystalline pure Ag specimens are compressed to 40 pct and annealed, there is no noticeable texture in the recrystallized\\u000a structure, and normal or abnormal grain growth occurs during annealing. When annealed further in low vacuum (10?3 to 10?4 Torr) after the completion of recrystallization, normal grain growth occurs at 920 C and 800 C, but abnormal grain growth\\u000a (AGG)

Jae Bon Koo; Duk Yong Yoon

2001-01-01

64

Effects of ionizing radiation and annealing of thin film MOS capacitors  

Microsoft Academic Search

In this paper an investigation of the effects of ionizing radiation damage and subsequent annealing of thin film (10.0-5 nm) MOS capacitors is reported. Isochronal annealing of the oxides was performed in vacuum for 90 min in the temperature range of 50-110C with a 20C increment. Studies were performed on very high dose X-ray irradiated samples to ascertain if annealing

P. K. Bhattacharya; Sunil K. Andhole; A. D. Savio

1992-01-01

65

Plasma Buildup and Breakdown Delay in a Triggered Vacuum Gap  

Microsoft Academic Search

The phenomena leading to the surface flashover across solid insulators in vacuum and the subsequent spread of the trigger plasma thus formed to bridge the main gap in a triggered vacuum switch are investigated experimentally. The results show that the breakdown proceeds in two stages. In the first stage a plasma is formed by electrons releasing and ionizing absorbed gases.

A. J. Green; C. Christopoulos

1979-01-01

66

Vacuum phenomena in insufficiency fractures of the sacrum  

Microsoft Academic Search

Objective. Insufficiency fractures of the sacrum are found in women who have undergone radiation therapy to the lower abdomen as well\\u000a as those suffering from osteoporosis of postmenopausal, steroid-induced, or primary biliary cirrhosis-related origin. Increased\\u000a up-take in bone scintigraphy and osteolytic changes in these fractures can be misinterpreted as bone metastases, leading to\\u000a unnecessary biopsies and other procedures in the

Axel Stiibler; Reiner Beck; Reiner Bartl; Dorothea Schmidt; Maximilian Reiser

1995-01-01

67

Laser annealing of LTPS  

Microsoft Academic Search

Laser annealing has become the primary method for producing the Low-Temperature-Poly-Silicon (LTPS) panels used in the Flat Panel Display (FPD) industry. Thin Film Transistor (TFT) backplanes based on LTPS substrates for Active Matrix Liquid Crystal Displays (AMLCD) offer substantial advantages over TFT backplanes based on amorphous silicon. The trend to higher pixel density, the integration of more driver and logic

Rainer Paetzel; Ludolf Herbst; Frank Simon

2006-01-01

68

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

69

GenAnneal: Genetically modified Simulated Annealing  

NASA Astrophysics Data System (ADS)

A modification of the standard Simulated Annealing (SA) algorithm is presented for finding the global minimum of a continuous multidimensional, multimodal function. We report results of computational experiments with a set of test functions and we compare to methods of similar structure. The accompanying software accepts objective functions coded both in Fortran 77 and C++. Catalogue identifier:ADXI_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADXI_v1_0 Program available from: CPC Program Library, Queen's University of Belfast, N. Ireland Computer for which the program is designed and others on which it has been tested: The tool is designed to be portable in all systems running the GNU C++ compiler Installation: University of Ioannina, Greece on Linux based machines Programming language used:GNU-C++, GNU-C, GNU Fortran 77 Memory required to execute with typical data: 200 KB No. of bits in a word: 32 No. of processors used: 1 Has the code been vectorized or parallelized?: No No. of bytes in distributed program, including test data, etc.:84?885 No. of lines in distributed program, including test data, etc.:14?896 Distribution format: tar.gz Nature of physical problem: A multitude of problems in science and engineering are often reduced to minimizing a function of many variables. There are instances that a local optimum does not correspond to the desired physical solution and hence the search for a better solution is required. Local optimization techniques are frequently trapped in local minima. Global optimization is hence the appropriate tool. For example, solving a non-linear system of equations via optimization, employing a least squares type of objective, one may encounter many local minima that do not correspond to solutions (i.e. they are far from zero). Typical running time: Depending on the objective function. Method of solution: We modified the process of step selection that the traditional Simulated Annealing employs and instead we used a global technique based on grammatical evolution.

Tsoulos, Ioannis G.; Lagaris, Isaac E.

2006-05-01

70

Effects of Oxygen Gas Annealing on Electrical Properties and Internal Stress in Indium Tin Oxide Films  

NASA Astrophysics Data System (ADS)

Indium tin oxide (ITO) films prepared by d.c. magnetron sputtering were annealed in air, vacuum, and oxygen gas atmosphere. The electrical properties and internal stresses of these annealed ITO films were systematically investigated. It was found that, among the above post-annealing treatments, oxygen gas annealing significantly reduced both the resistivity and the internal stress in ITO films at fairly low temperatures of 100-150C. Resistivities and internal stresses as low as 7 10-4 ?{\\cdot}cm and 38 MPa, respectively, were obtained by annealing in oxygen gas atmosphere at 100C. It was also revealed that the (111) crystal orientation becomes dominant and that whole grains grow dramatically as a result of post-oxygen-annealing, even at 100C.

Takayama, Shinji; Tanaka, Akira; Sugawara, Toshifumi; Himuro, Tokuji

2002-06-01

71

Laser sealed vacuum insulation window  

DOEpatents

A laser sealed evacuated window panel is comprised of two glass panes held spaced apart in relation to each other by a plurality of spherical glass beads and glass welded around the edges to provide an evacuated space between the glass panes that is completely glass sealed from the exterior. The glass welded edge seal is obtained by welding the edges of the glass panes together with a laser beam while the glass panes and bead spacers are positioned in a vacuum furnace and heated to the annealing point of the glass to avoid stress fracture in the area of the glass weld. The laser welding in the furnace can be directed around the perimeter of the glass panel by a combination of rotating the glass panel and linearly translating or aiming the laser with a relay mirror.

Benson, David K. (Golden, CO); Tracy, C. Edwin (Golden, CO)

1987-01-01

72

Laser sealed vacuum insulating window  

DOEpatents

A laser sealed evacuated window panel is comprised of two glass panes held spaced apart in relation to each other by a plurality of spherical glass beads and glass welded around the edges to provide an evacuated space between the glass panes that is completely glass sealed from the exterior. The glass welded edge seal is obtained by welding the edges of the glass panes together with a laser beam while the glass panes and bead spacers are positioned in a vacuum furnace and heated to the annealing point of the glass to avoid stress fracture in the area of the glass weld. The laser welding in the furnace can be directed around the perimeter of the galss panel by a combination of rotating the glass panel and linearly translating or aiming the laser with a relay mirror.

Benson, D.K.; Tracy, C.E.

1985-08-19

73

Effects of H2 Atmosphere Annealing on the Properties of CZT:In Single Crystals  

NASA Astrophysics Data System (ADS)

To improve crystal quality and detector performance, high-resistivity cadmium zinc telluride (CZT):In single crystals were annealed in H2. The concentration of Te inclusions did not change after annealing. Both the resistivity and infrared transmittance increased as the annealing time increased, indicating improvement of crystal quality. Because of the passivation by hydrogen, some interesting phenomena were observed in the photoluminescence spectra of as-grown and annealed CZT:In crystals. Moreover, the energy resolution was remarkably enhanced. After 4 h, 8 h, and 12 h of annealing, the energy resolution was improved 33%, 79%, and 49%, respectively. The crystal annealed for 8 h with energy resolution of 9.29% had the best detector performance.

Yu, P. F.; Jie, W. Q.

2013-09-01

74

Mathematical model of the short arc phenomena at the initial stage  

Microsoft Academic Search

A mathematical model is presented describing transient phenomena accompanied by a vacuum short arc at the initial stage of contact opening. It enables one to describe the evolution of transient short anode dominated arc, which appears just after the rupture of molten bridge, into diffusive cathode dominated arc. The model of an vacuum arc includes equations for the cathode region

S. N. Kharin

1997-01-01

75

Vacuum packaging technology using localized aluminum\\/silicon-to-glass bonding  

Microsoft Academic Search

A vacuum package based on localized aluminum\\/silicon-to-glass bonding has been successfully demonstrated. With 3.4 watts heating power, ~0.2 MPa applied contact pressure, and 90 minutes wait time before bonding, vacuum encapsulation at 25 mtorr can be achieved. Folded-beam comb drive ?-resonators are encapsulated and used as pressure monitors. Long-term testing of un-annealed vacuum-packaged ?-resonators with a Q of 2500 has

Y. T. Cheng; W. T. Hsu; L. Lin; C. T. Nguyen; K. Najafi

2001-01-01

76

Annealing-induced property improvements in 2-14-1 powders produced by inert gas atomization  

SciTech Connect

The effects of vacuum annealing on the phase constitution and magnetic properties of various size fractions of 3 alloy compositions produced by Inert-gas atomization (IGA) are examined. Annealing results in the oxidation of properitectic {alpha}-Fe formed during cooling of the melt, producing considerable improvement in the hard magnetic properties of the powders largely via the removal of lower-anisotropy magnetic reversal regions.

Lewis, L.H. [Brookhaven National Lab., Upton, NY (United States). Dept. of Applied Science; Sellers, C.H. [Lockheed Idaho Technologies Co., Idaho Falls, ID (United States); Panchanathan, V. [Magnequench International Inc., Anderson, IN (United States)

1996-04-01

77

Effect of cold rolling and annealing on mechanical properties of HSLA steel  

Microsoft Academic Search

Purpose: was to examine effect of the parameters of cold deformation and recrystallization annealing on mechanical properties of a Nb-microalloyed HSLA steel. Design\\/methodology\\/approach: Research of strip steel QStE 420 was based on a combination of laboratory cold rolling, recrystallization annealing in vacuum furnace, mechanical (particularly tensile) tests and metallographic analyses. Findings: It was validated that by a sophisticated combination of

I. Schindler; M. Janoec; E. Msteck; L. A. Dobrzaski; S. Rusz

78

Annealing Temperature Effect on the Field Emission Properties of Carbon Nanotube Films  

Microsoft Academic Search

As the carbon nanotubes (CNTs) films are applied to the field emission cathodes in the vacuum devices, heat treatment in the range of 400C-500C is often conducted during the device sealing process, especially for glass-based devices. The annealing temperature effect on the field emission of the CNT films prepared by chemical vapor deposition is investigated. The CNT film annealed at

T. Chen; Z. Sun; L. L. Wang; Y. W. Chen; P. S. Guo; W. X. Que

2007-01-01

79

Investigation of Impact Behavior of Cold-Sprayed Large Annealed Copper Particles and Characterization of Coatings  

Microsoft Academic Search

In this research, the large gas-atomized copper powder was selected as the feedstock. Some powder was annealed in a vacuum\\u000a circumstance to avoid the effect of grain boundaries on the high velocity impact behavior of particles during cold spraying.\\u000a The annealed Cu powder was deposited by cold spraying with respect to the single impacts and coating deposition under certain\\u000a gas

Wenya Li; Xueping Guo; Min Yu; Hanlin Liao; Christian Coddet

2011-01-01

80

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

81

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

82

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

83

X-Ray Photoelectron Spectroscopy and Tribology Studies of Annealed Fullerene-like WS2 Nanoparticles  

NASA Astrophysics Data System (ADS)

The temporal chemical changes occurring at the surface of fullerene-like (IF) nanoparticles of WS2 were investigated using X-ray photo-electron spectroscopy (XPS) and compared to those of bulk powder (2H) of the same material. It is possible to follow the long term (surface oxidation and carbonization) occurring at defects on the outermost surface (0001) layer of the fullerene-like nanoparticles. Similar but perhaps more distinctive changes are observed on the prismatic (hk0) surfaces of the 2H powder. Vacuum annealing is shown to remove most of these changes and bring the surface close to its stoichiometric composition. In accordance with previous measurements, further evidence is obtained for the existence of water molecules which are entrapped in the hollow core and interstitial defects of the fullerene-like nanoparticles during the synthesis. They are also shown to be removed by the vacuum annealing process. Chemically resolved electrical measurements (CREM) in the XPS show that the vacuum annealed IF samples become more intrinsic. Finally, tribological measurements show that the vacuum annealed IF samples perform better as an additive to oil than the non-annealed IF samples and the bulk (2H) platelets powder.

Kopnov, F.; Tenne, R.; Spth, B.; Jgermann, W.; Cohen, H.; Feldman, Y.; Zak, A.; Moshkovich, A.; Rapoport, L.

84

Crystallization and thermochromism of annealed heterostructures containing titanium and tungsten oxide films  

NASA Astrophysics Data System (ADS)

Crystalline phases in heterostructures containing titanium and tungsten oxide films are studied after step annealing in vacuum at temperatures between 500 and 750C. The films are deposited on a silica glass substrate by dc reactive magnetron sputtering. It is found that crystalline phases in single layers and bilayer structures form in a different way. In the latter, crystallization is influenced by the order of layer arrangement on the substrate. Thermochromism in structures annealed in vacuum is due to the oxygen-deficient phase WO3 - x belonging to the hexagonal syngony. This phase intensely grows as the temperature rises from 650 to 750C.

Shapovalov, V. I.; Lapshin, A. E.; Komlev, A. E.; Arsent'ev, M. Yu.; Komlev, A. A.

2013-09-01

85

Ion exchange phenomena  

SciTech Connect

Ion exchange phenomena involve the population of readily exchangeable ions, the subset of adsorbed solutes that balance the intrinsic surface charge and can be readily replaced by major background electrolyte ions (Sposito, 2008). These phenomena have occupied a central place in soil chemistry research since Way (1850) first showed that potassium uptake by soils resulted in the release of an equal quantity of moles of charge of calcium and magnesium. Ion exchange phenomena are now routinely modeled in studies of soil formation (White et al., 2005), soil reclamation (Kopittke et al., 2006), soil fertilitization (Agbenin and Yakubu, 2006), colloidal dispersion/flocculation (Charlet and Tournassat, 2005), the mechanics of argillaceous media (Gajo and Loret, 2007), aquitard pore water chemistry (Tournassat et al., 2008), and groundwater (Timms and Hendry, 2007; McNab et al., 2009) and contaminant hydrology (Chatterjee et al., 2008; van Oploo et al., 2008; Serrano et al., 2009).

Bourg, I.C.; Sposito, G.

2011-05-01

86

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

87

Vacuum String Field Theory  

Microsoft Academic Search

This is a brief review of vacuum string field theory, a new approach to open string field theory based on the stable vacuum of the tachyon. We discuss the sliver state explaining its role as a projector in the space of half-string functionals. We review the construction of D-brane solutions in vacuum string field theory, both in the algebraic approach

Leonardo Rastelli; Ashoke Sen; Barton Zwiebach

2001-01-01

88

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

89

Flow phenomena in turbomachines  

NASA Astrophysics Data System (ADS)

This report describes work carried out at the Gas Turbine Laboratory at MIT during the period 10/20/89 - 10/19/92, as part of our multi-investigator effort on basic unsteady flow phenomena in turbomachines. Within the overall project four separate tasks are specified. These are, in brief: (1) The Influence of Inlet Temperature Nonuniformities on Turbine Heat Transfer and Dynamics; (2) Assessment of Unsteady Losses in Stator/ Rotor Interactions; (3) Unsteady Phenomena and Flowfield instabilities in Multistage Axial Compressors; (4) Vortex Wake-Compressor Blade Interaction in Cascades - A New Rapid Method for Unsteady Separation and Vorticity Flux Calculations.

Creitzer, E. M.; Epstein, A. H.; Giles, M. B.; McCune, J. E.; Tan, C. S.

1993-01-01

90

Imaging of snapping phenomena  

PubMed Central

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.

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

2012-01-01

91

Experimental signatures of quantum annealing  

NASA Astrophysics Data System (ADS)

Quantum annealing is a general strategy for solving optimization problems with the aid of quantum adiabatic evolution. How effective is rapid decoherence in precluding quantum effects in a quantum annealing experiment, and will engineered quantum annealing devices effectively perform classical thermalization when coupled to a decohering thermal environment? Using the D-Wave machine, we report experimental results for a simple problem which takes advantage of the fact that for quantum annealing the measurement statistics are determined by the energy spectrum along the quantum evolution, while in classical thermalization they are determined by the spectrum of the final Hamiltonian only. We establish an experimental signature which is consistent with quantum annealing, and at the same time inconsistent with classical thermalization, in spite of a decoherence timescale which is orders of magnitude shorter than the adiabatic evolution time. For larger and more difficult problems, we compare the measurements statistics of the D-Wave machine to large-scale numerical simulations of simulated annealing and simulated quantum annealing, implemented through classical and quantum Monte Carlo simulations. For our test cases the statistics of the machine are - within calibration uncertainties - indistinguishable from a simulated quantum annealer with suitably chosen parameters, but significantly different from a classical annealer.

Boixo, Sergio

2013-03-01

92

Germanium detector vacuum encapsulation  

SciTech Connect

The encapulation of germanium detectors has been a long sought after goal. We have begun to develop 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 in the paper.

Madden, N.W.; Malone, D.F.; Phel, R.H.; Cork, C.P.; Luke, P.N.; Landis, D.A.; Pollard, M.J. (Lawrence Berkeley Laboratory, University of California, Berkeley, CA 94720 (United States))

1991-08-01

93

Annealing effects on the magnetic properties of a multifilamentary Cu-Nb composite  

NASA Astrophysics Data System (ADS)

In this paper, the annealing effects on the magnetic properties of a multifilamentary Cu-15vol%Nb composite were investigated. During vacuum annealing, noticeable changes take place in the microstructure, mostly the partial spheroidization and further coarsening of the niobium filaments. Results show that spheroidization becomes noticeable at about 700 C and, even after annealing at severe conditions, e.g. 1050 C for 32 h, the continuity of the niobium-conducting path is partially preserved. The influence of these microstructural changes on the magnetic properties of the multifilamentary Cu-Nb composite conductor is discussed.

Sandim, M. J. R.; Sandim, H. R. Z.; Shigue, C. Y.; Filgueira, M.; Ghivelder, L.

2003-03-01

94

Growth and Annealing Influence on Structural and Optical Properties of Nanostructured ZIO Thin Films  

NASA Astrophysics Data System (ADS)

Zinc-Indium-Oxide (ZIO) thin films were deposited on glass substrate with varying concentrations (ZnO:In2O3-100:0, 90:10, 70:30 and 50:50 wt%) at room temperature by flash evaporation technique. These deposited ZIO film were annealed at 450 C in vacuum. These films were characterized to study the effect of annealing on the structural and optical properties. Atomic force microscopy (AFM) images manifest the surface morphology of these ZIO thin films. The apparent growth of surface features revealed the formation of nanostructured ZIO thin films. The optical transmittance found to be decreased however blue shift has been observed after annealing.

Jain, Vipin Kumar; Kumar, Praveen; Jain, Praveen; Srivastava, S.; Vijay, Y. K.

2011-07-01

95

Influence of annealing on composition and optical properties of CdTe nanoparticle layer-by-layer films.  

PubMed

CdTe nanoparticle-polymer composite films were deposited conformally using a layer-by-layer (LbL) process onto planar or ZnO nanorod-coated substrates. Films were annealed between 150-450 degrees C. Under air this led to oxidation of the nanoparticles while under vacuum their composition was retained. Annealing at 450 degrees C led to complete removal of the polymer with a loss of quantum confinement as shown by UV-vis spectroscopy. Annealing at 350 degrees C gave partial removal of the polymer and retained quantum confinement. Such annealed nanoparticle composite systems may have application in photovoltaics. PMID:21770174

Briscoe, Joe; Gallardo, Diego E; Lesnyak, Vladimir; Dunn, Steve

2011-06-01

96

Annealing of nitrogen-doped ZnSe at high pressures: Toward suppression of native defect formation  

SciTech Connect

Pressure is shown to have a drastic effect an the annealing characteristics of p-type, nitrogen-doped ZnSe. Samples annealed in vacuum show decreased carrier concentrations and simultaneous formation of deep-donor-related luminescence, while samples annealed under pressure show suppression of this compensating donor. Results are interpreted as an increase in the formation energy of the compensating deep donor under pressure. In addition the samples annealed under pressure show emergence of a new, intense, green luminescence band centered at 2.44 eV. The magnitude of the shift of this Peak under applied stress suggests that it results from a recombination involving a deep acceptor.

Chen, A.L.; Walukiewicz, W. [Lawrence Berkeley Lab., CA (United States); Haller, E.E. [Lawrence Berkeley Lab., CA (United States)]|[Brookhaven National Lab., Upton, NY (United States); Luo, H.; Karczewski, G.; Furdyna, J. [University of Notre Dame, Notre Dame, IN (United States). Dept. of Physics

1994-07-01

97

COLLECTIVE PHENOMENA IN ACCELERATORS  

Microsoft Academic Search

Recent years have witnessed the development of accelerators of ever-larger current, both peak and average, as well as a proliferation of storage rings of ever-greater luminosity. Consequently, there is considerable interest in and growing concern with, the phenomena which limit beam currents and beam densities, namely, the collective modes of behavior of relativistic particle beams. Furthermore, it has been demonstrated

Sessler; Andrew M

1972-01-01

98

Solar cosmic ray phenomena  

Microsoft Academic Search

This review attempts to present an integrated view of the several types of solar cosmic ray phenomena. The relevant large and small scale properties of the interplanetary medium are first surveyed, and their use in the development of a quantitative understanding of the cosmic ray propagation processes summarised. Solar cosmic ray events, in general, are classified into two phenomenological categories:

K. G. McCracken; U. R. Rao

1970-01-01

99

Wave Phenomena Simulations  

NSDL National Science Digital Library

This resource contains interactive wave motion simulations for students in introductory physics classes. The various simulations model phenomena such as wave superposition, reflection, and refraction, as well as the interference of waves, the Doppler effect, the superposition of sine waves, and the various intensities of spherical waves.

Taylor, Barney

2003-10-10

100

A Cold-Bore Vacuum System Design for POPAE  

Microsoft Academic Search

We have made a conceptual design of a cold-bore vacuum system for the Fermilab 1000 GeV ?? 1000 GeV colliding beam facility (POPAE). A double wall vacuum system is used between magnets and cryopumped molecular traps between the cold-bore and warm straight section regions. The beam-induced pressure rise phenomena has been taken into account as well as the liquid helium

Y. Cho; T. K. Khoe; J. Moenich; L. G. Ratner

1977-01-01

101

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

102

Semantic search via concept annealing  

Microsoft Academic Search

Annealing, in metallurgy and materials science, is a heat treatment wherein the microstructure of a material is altered, causing changes in its properties such as strength and hardness. We define concept annealing as a lexical, syntactic, and semantic expansion capability (the removal of defects and the internal stresses that cause term- and phrase-based search failure) coupled with a directed contraction

Kirk A. Dunkelberger

2007-01-01

103

Simulated Annealing with Opposite Neighbors  

Microsoft Academic Search

This paper presents an improvement to the vanilla version of the simulated annealing algorithm by using opposite neighbors. This new technique, is based on the recently proposed idea of opposition based learning, as such our proposed algorithm is termed opposition-based simulated annealing (OSA). In this paper we provide a theoretical basis for the algorithm as well as its practical implementation.

Mario Ventresca; Hamid R. Tizhoosh

2007-01-01

104

Unit commitment by simulated annealing  

Microsoft Academic Search

A general optimization method, known as simulated annealing, is applied to generation unit commitment. By exploiting the resemblance between a minimization process and the cooling of a molten metal, simulated annealing generates feasible solutions randomly and moves among these solutions using a strategy leading to a global minimum with high probabilities. The method assumes no specific problem structures and is

F. Zhuang; F. D. Galiana

1990-01-01

105

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

106

Vacuum pump aids ejectors  

SciTech Connect

The steam ejector/vacuum pump hybrid system has been operating satisfactorily since the summer of 1981. This system has essentially been as troublefree as the all-ejector system and, of course, has provided a substantial cost savings. Construction is currently under way to convert the vacuum system of another crude still which is equipped with steam ejectors and barometric condensers to the hybrid system of steam ejectors, surface condensers, and vacuum pumps. This current project is even more financially attractive because it allows a dirty water cooling tower which serves the barometric condensers to be shut down. Providing a vacuum for crude distillation vacuum towers with this hybrid system is by no means the only application of this technique. Any vacuum system consisting of all steam ejectors would be a candidate for this hybrid system and the resulting savings in energy.

Nelson, R.E.

1982-12-01

107

?-vacuum and inflationary bispectrum  

Microsoft Academic Search

In this paper, we discuss the non-Gaussianity originated from the ?-vacuum on the CMB anisotropy. For ?-vacuum, there exist correlation between points in the acausal two patches of de Sitter spactime. Such kind of correlation can lead to large local form non-Gaussianity in ?-vacuum. For the single field slow- roll inflationary scenario, the spacetime is in a quasi-de Sitter phase

Wei Xue

2009-01-01

108

Effect of annealing ambient on electrical and optical properties of Ga-doped MgxZn1-xO films  

NASA Astrophysics Data System (ADS)

2 at.% Ga-doped MgxZn1-xO (x = 0-8%) films have been prepared by sol-gel dip-coating method, and the effects of three different post annealing ambient: (a) vacuum annealing under air pressure of 10-2 Pa; (b) annealing in nitrogen atmosphere, and (c) annealing in argon-hydrogen (96%argon + 4%hydrogen) atmosphere on the electrical and optical properties of the films are investigated. When treated by these three different post-annealing ambient, both the resisitivity and band gap of the films increase with Mg doping contents increasing from 0 to 8 at.%. The vacuum annealed films show much lower resistivity than those treated in nitrogen or argon-hydrogen atmosphere, and the transmittance of the vacuum annealed films (70%) is also lower than those annealed by the other two methods (90%) in visible region. It shows that different post annealing ambient and ion doping could modify the optoelectronic properties of ZnO films.

Liu, Jinming; Zhao, Xiaoru; Duan, Libing; Sun, Huinan; Bai, Xiaojun; Chen, Liu; Chen, Changle

2012-06-01

109

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

110

The phenomena of inner experience  

Microsoft Academic Search

This study provides a survey of phenomena that present themselves during moments of naturally occurring inner experience. In our previous studies using Descriptive Experience Sampling (DES) we have discovered five frequently occurring phenomenainner speech, inner seeing, unsymbolized thinking, feelings, and sensory awareness. Here we quantify the relative frequency of these phenomena. We used DES to describe 10 randomly identified moments

Christopher L. Heavey; Russell T. Hurlburt

2008-01-01

111

Vacuuming radioactive sludge  

ScienceCinema

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.

112

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

113

Vacuum technology for ITER  

Microsoft Academic Search

The vacuum systems for ITER are characterized by the requirements for tritium compatibility, tolerance of high magnetic and radiation fields and remote maintainability. In addition, although the vacuum levels are relatively modest, high pumping speeds are needed to achieve the high gas throughputs required. The design solutions adopted, the status of the development programme and the issues still to be

D. Murdoch; A. Antipenkov; C. Caldwell-Nichols; C. Day; M. Dremel; H. Haas; V. Hauer; H. Jensen

2008-01-01

114

The ITER vacuum systems  

Microsoft Academic Search

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

C. Day; D. Murdoch

2008-01-01

115

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

116

Effect of surface ion exchange of machinable ceramic on its flashover characteristics in vacuum  

Microsoft Academic Search

As well known, the surface conditions of solid materials strongly affect the flashover phenomena under high electric field in vacuum. On the basis of the novel low melting temperature machinable glass ceramics for vacuum insulation system, which has excellent machinable performance and good electrical properties, the ion-exchange method was used to change the sample's surface condition, surface electric resistivity and

Xue-Zeng Huang; Kai-Kun Yu; Guan-Jun Zhang; Nan Zheng; Jie Tian; Guang-Xin Li; Xin-Pei Ma; Yasushi Yamano; Shinichi Kobayashi

2010-01-01

117

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

118

About the connection between vacuum birefringence and the light light scattering amplitude  

NASA Astrophysics Data System (ADS)

Birefringence phenomena stemming from vacuum polarization are revisited in the framework of coherent scattering. Based on photon-photon scattering, our analysis brings out the direct connection between this process and vacuum birefringence. We show how this procedure can be extended to the Kerr and the Cotton-Mouton birefringences in vacuum, thus providing a unified treatment of various polarization schemes, including those involving static fields.

Hassinski, J.; Dagoret, S.; Urban, M.; Zomer, F.

2006-12-01

119

Investigations of Pulsed Vacuum Gap.  

National Technical Information Service (NTIS)

Past research and the current status of understanding of electrical breakdown of vacuum is reviewed. This review includes DC, AC and pulsed vacuum gap breakdown. Measurements have been performed to determine the role of microparticles in pulsed vacuum gap...

J. E. Thompson T. S. Sudarshan J. M. Butner

1981-01-01

120

MMH\\/NTO injection and ignition in vacuum downstream from an Aestus engine single injection element  

Microsoft Academic Search

An experimental study of the injection and ignition of MMH and NTO propellants injected under vacuum conditions downstream from an Aestus rocket-engine single element injector was undertaken to investigate the physical phenomena occurring during the first steps of injection and ignition in the actual conditions of the Aestus engine. A laser sheet technique was used to visualize the phenomena in

Renaud Lecourt; Franois-Xavier d'Herbigny

2004-01-01

121

Laser annealing of amorphous carbon films  

NASA Astrophysics Data System (ADS)

Amorphous ( a-C) Carbon thin films were deposited, using pulsed laser deposition (PLD) with a Nd:YAG laser (1064 nm, 7 ns), from a pyrolytic graphite target, on <1 0 0> silicon and refractory metal (Mo) substrates to a film thickness of 55, 400 and 500 nm. Samples were grown at RT and then annealed by a laser annealing technique, to reduce residual stress and induce a locally confined "graphitization" process. The films were exposed to irradiation, in vacuum, by a Nd:YAG pulsed laser, operating at different wavelengths (VIS, N-UV) and increasing values of energy from 6-100 mJ/pulse. The thinner films were completely destroyed by N-UV laser treatment also at lower energies, owing to the almost direct propagation of heat to the Si substrate with melting and ruinous blistering effects. For thicker films the Raman micro-analysis evidenced the influence of laser treatments on the sp 3/sp 2 content evolution, and established the formation of aromatic nano-structures of average dimension 4.14.7 nm (derived from the ID/ IG peak ratio), at fluence values round 50 mJ/cm 2 for N-UV and 165 mJ/cm 2 for VIS laser irradiation. Higher fluences were not suitable for a-Carbon "graphitization", since a strong ablation process was the prominent effect of irradiation. Grazing incidence XRD (GI-XRD) used to evaluate the dimension and texturing of nano-particles confirmed the findings of Raman analysis. The effects of irradiation on surface morphology were studied by SEM analysis.

Cappelli, E.; Scilletta, C.; Orlando, S.; Valentini, V.; Servidori, M.

2009-03-01

122

Transport phenomena in nanofluidics  

NASA Astrophysics Data System (ADS)

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 and practical achievements. This review focuses on the physical properties and operational mechanisms of the most common structures, such as nanometer-sized openings and nanowires in solution on a chip. Since the surface-to-volume ratio increases with miniaturization, this ratio is high in nanochannels, resulting in surface-charge-governed transport, which allows ion separation and is described by a comprehensive electrokinetic theory. The charge selectivity is most pronounced if the Debye screening length is comparable to the smallest dimension of the nanochannel cross section, leading to a predominantly counterion containing nanometer-sized aperture. These unique properties contribute to the charge-based partitioning of biomolecules at the microchannel-nanochannel interface. Additionally, at this free-energy barrier, size-based partitioning can be achieved when biomolecules and nanoconstrictions have similar dimensions. Furthermore, nanopores and nanowires are rooted in interesting physical concepts, and since these structures demonstrate sensitive, label-free, and real-time electrical detection of biomolecules, the technologies hold great promise for the life sciences. The purpose of this review is to describe physical mechanisms on the nanometer scale where new phenomena occur, in order to exploit these unique properties and realize integrated sample preparation and analysis systems.

Schoch, Reto B.; Han, Jongyoon; Renaud, Philippe

2008-07-01

123

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

Microsoft Academic Search

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

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

2005-01-01

124

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

125

Microstructure Changes of Plasma Spraying Tungsten Coatings on Cfc after Different Temperature Annealing  

NASA Astrophysics Data System (ADS)

Thermal behaviors of tungsten coating of 0.5 mm thick with multi-layers interface of tungsten (W) and rhenium (Re) coated on CFC (CX-2002U) substrate by vacuum plasma spraying (VPS) technique were examined by annealing with an electron beam thermal load facility between 1200 C and 2000 C. Change of the microstructure was observed and its chemical composition was analyzed by EDS after annealing. It was observed that remarkable recrystallization of VPS-W occurred above 1400 C. The structure of the multi-layers of W and Re become obscure by the mutual diffusion of W, Re and C above 1600C and finally disappeared after annealing at 2000 C for one hour. Very hard tungsten carbides are formed at the interface above 1600 C and they were broadening with increasing annealing temperature and time.

Liu, X.; Tamura, S.; Tokunaga, K.; Yoshida, N.; Noda, N.

2003-06-01

126

Origin of new broad Raman d and g peaks in annealed graphene.  

PubMed

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. PMID:24048447

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

2013-09-19

127

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

128

Three-dimensional transient temperature field model for laser annealing  

SciTech Connect

A three-dimensional transient temperature field model (TTFM) is proposed for the general problem of laser-induced out-of-equilibrium annealing of a bilayer device, which is made up of a bulk material covered by a transparent layer. The TTFM solves the moving-boundary problem with a deterministic relation between the interface velocity and temperature in contrast to preceding problem-dependent models, which use an interface-tracking heuristic algorithm. The TTFM is the first step to model many temperature-driven phenomena such as diffusion and segregation in laser annealing. Both computed transient temperature field and melted-zone dimensions of a SiO{sub 2}/Si example device, which is irradiated by a focused visible (532 nm) laser, are in very good agreement with experimental measurements.

Degorce, Jean-Yves; Gillet, Jean-Numa; Magny, Francois; Meunier, Michel [Department of Engineering Physics, Ecole Polytechnique de Montreal, Laser Processing Laboratory, C.P. 6079, succ. Centre-ville, Montreal, Quebec H3C 3A7 (Canada)

2005-02-01

129

Collapse of vacuum bubbles in a vacuum  

SciTech Connect

We revisit the dynamics of a false vacuum bubble in a background de Sitter spacetime. We find that there exists a large parameter space that allows the bubble to collapse into a black hole or to form a wormhole. This may have interesting implications for the creation of a baby universe in the laboratory, the string landscape where the bubble nucleation takes place among a plenitude of metastable vacua, and the inflationary physics.

Ng, Kin-Wang; Wang, Shang-Yung [Institute of Physics, Academia Sinica, Taipei, Taiwan 11529 (China); Department of Physics, Tamkang University, Tamsui, Taiwan 25137 (China)

2011-02-15

130

Annealing and oxidation of silicon oxide films prepared by plasma-enhanced chemical vapor deposition  

SciTech Connect

We have investigated phase separation, silicon nanocrystal (Si NC) formation and optical properties of Si oxide (SiO{sub x}, 0vacuum annealing and dry oxidation. The SiO{sub x} films were deposited by plasma-enhanced chemical vapor deposition at different nitrous-oxide/silane flow ratios. The physical and optical properties of the SiO{sub x} films were studied as a result of high-vacuum annealing and thermal oxidation. X-ray photoelectron spectroscopy (XPS) reveals that the as-deposited films have a random-bonding or continuous-random-network structure with different oxidation states. After annealing at temperatures above 1000 deg. C, the intermediate Si continuum in XPS spectra (referring to the suboxide) split to Si peaks corresponding to SiO{sub 2} and elemental Si. This change indicates the phase separation of the SiO{sub x} into more stable SiO{sub 2} and Si clusters. Raman, high-resolution transmission electron microscopy and optical absorption confirmed the phase separation and the formation of Si NCs in the films. The size of Si NCs increases with increasing Si concentration in the films and increasing annealing temperature. Two photoluminescence (PL) bands were observed in the films after annealing. The ultraviolet (UV)-range PL with a peak fixed at 370-380 nm is independent of Si concentration and annealing temperature, which is a characteristic of defect states. Strong PL in red range shows redshifts from {approx}600 to 900 nm with increasing Si concentration and annealing temperature, which supports the quantum confinement model. After oxidation of the high-temperature annealed films, the UV PL was almost quenched while the red PL shows continuous blueshifts with increasing oxidation time. The different oxidation behaviors further relate the UV PL to the defect states and the red PL to the recombination of quantum-confined excitions.

Chen, X.Y.; Lu, Y.F.; Tang, L.J.; Wu, Y.H.; Cho, B.J.; Xu, X.J.; Dong, J.R.; Song, W.D. [Department of Electrical and Computer Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260 (Singapore); Department of Electrical Engineering, University of Nebraska, Lincoln, Nebraska 68588-0511 (United States); Institute of Microelectronics, 11 Science Park Road, Singapore 117685 (Singapore); Department of Electrical and Computer Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260 (Singapore); Institute of Materials Research and Engineering, 3 Research Link, Singapore 117602 (Singapore); Data Storage Institute, 5 Engineering Drive 1, Singapore 117608 (Singapore)

2005-01-01

131

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

132

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

133

Hysteresis phenomena in hydraulic measurement  

NASA Astrophysics Data System (ADS)

Hysteresis phenomena demonstrate the lag between the generation and the removal of some physical phenomena. This paper studies the hysteresis phenomena of the head-drop in a scaled model pump turbine using experiment test and CFD methods. These lag is induced by complicated flow patterns, which influenced the reliability of rotating machine. Keeping the same measurement procedure is concluded for the hydraulic machine measurement.

Ran, H. J.; Luo, X. W.; Chen, Y. L.; Xu, H. Y.; Farhat, M.

2012-11-01

134

Superconducting properties of two-step in situ annealed MgB2 thin films  

NASA Astrophysics Data System (ADS)

We have investigated the effects of in situ annealing on the superconducting properties of MgB2 thin films for the purpose of obtaining high critical temperature close to bulk value. MgB2 thin films were fabricated by rf magnetron sputtering on C-plane sapphire (Al2O3) substrate. Thin films were produced by simultaneously sputtering pure B and a Mg metal target. Sputtering deposition was followed by in situ annealing in a high vacuum. To prevent the evaporation of Mg from the film surface, two-step annealing was adopted: the first step is the crystallization stage at low-temperature annealing and the next is an improvement of the film's superconducting properties by annealing at a high temperature. In the optimal annealing process (a thin film is first heated at 600 C for 2 h and then 670 C for 2 h) we have consistently obtained thin films with a zero resistivity temperature of 33 K. We have discussed the cause of improvement of the superconducting properties of thin films by two-step annealing.

Mori, Zon; Doi, Toshiya; Ishizaki, Yuichiro; Kitaguchi, Hitoshi; Okada, Michiya; Saitoh, Kazuo; Hakuraku, Yoshinori

2004-10-01

135

Macroscopic length, lattice parameter and microstructural changes in neutron-irradiated aluminum nitride due to annealing  

NASA Astrophysics Data System (ADS)

Aluminum nitride was neutron-irradiated in the Japan Materials Testing Reactor up to 5.21024 n/m2 (E > 1.0 MeV). The specimens were isochronally annealed under a vacuum up to 1400C. The macroscopic length and lattice parameters of both a- and c-axis of the specimen irradiated to 8.3 1022 n/m2 at about 100C decreased concurrently with an increase in annealing temperature from 100C, and returned to the pre-irradiated values after annealing at 1100C. The macroscopic lengths of the specimens irradiated to 2.41024 n/m2 at 470C and 5.21024 n/m2 at 785C, both containing dense interstitial dislocation loops, were not significantly influenced by annealing up to 800-900C. Then they decreased rapidly with increasing annealing temperature up to 1400C. The change in c-axis lattice parameter by annealing was larger than that of a-axis above 900-1000C, and finally reduced to the pre-irradiated values after annealing at 1400C.

Yano, T.; Tezuka, M.; Miyazaki, H.; Iseki, T.

1992-09-01

136

Electromagnetic vacuum of complex media: Dipole emission versus light propagation, vacuum energy, and local field factors  

NASA Astrophysics Data System (ADS)

We offer a unified approach to several phenomena related to the electromagnetic vacuum of a complex medium made of point electric dipoles. To this aim, we apply the linear response theory to the computation of the polarization field propagator and study the spectrum of vacuum fluctuations. The physical distinction among the local density of states which enter the spectra of light propagation, total dipole emission, coherent emission, total vacuum energy, and Schwinger-bulk energy is made clear. Analytical expressions for the spectrum of dipole emission and for the vacuum energy are derived. Their respective relations with the spectrum of external light and with the Schwinger-bulk energy are found. The light spectrum and the Schwinger-bulk energy are determined by the Dyson propagator. The emission spectrum and the total vacuum energy are determined by the polarization propagator. An exact relationship of proportionality between both propagators is found in terms of local field factors. A study of the nature of stimulated emission from a single dipole is carried out. Regarding coherent emission, it contains two components. A direct one which is transferred radiatively and directly from the emitter into the medium and whose spectrum is that of external light. And an indirect one which is radiated by induced dipoles. The induction is mediated by one (and only one) local field factor. Regarding the vacuum energy, we find that in addition to the Schwinger-bulk energy the vacuum energy of an effective medium contains local field contributions proportional to the resonant frequency and to the spectral line width.

Donaire, M.

2011-02-01

137

Electromagnetic vacuum of complex media: Dipole emission versus light propagation, vacuum energy, and local field factors  

SciTech Connect

We offer a unified approach to several phenomena related to the electromagnetic vacuum of a complex medium made of point electric dipoles. To this aim, we apply the linear response theory to the computation of the polarization field propagator and study the spectrum of vacuum fluctuations. The physical distinction among the local density of states which enter the spectra of light propagation, total dipole emission, coherent emission, total vacuum energy, and Schwinger-bulk energy is made clear. Analytical expressions for the spectrum of dipole emission and for the vacuum energy are derived. Their respective relations with the spectrum of external light and with the Schwinger-bulk energy are found. The light spectrum and the Schwinger-bulk energy are determined by the Dyson propagator. The emission spectrum and the total vacuum energy are determined by the polarization propagator. An exact relationship of proportionality between both propagators is found in terms of local field factors. A study of the nature of stimulated emission from a single dipole is carried out. Regarding coherent emission, it contains two components. A direct one which is transferred radiatively and directly from the emitter into the medium and whose spectrum is that of external light. And an indirect one which is radiated by induced dipoles. The induction is mediated by one (and only one) local field factor. Regarding the vacuum energy, we find that in addition to the Schwinger-bulk energy the vacuum energy of an effective medium contains local field contributions proportional to the resonant frequency and to the spectral line width.

Donaire, M. [Centro de Fisica do Porto, Faculdade de Ciencias da Universidade do Porto, Rua do Campo Alegre 687, P-4169-007 Porto (Portugal); Departamento de Fisica de la Materia Condensada, Universidad Autonoma de Madrid, E-28049 Madrid (Spain)

2011-02-15

138

Effects of Post-Annealing on Oxygen Content of Indium Tin Oxide Films Fabricated by Reactive Sputtering  

NASA Astrophysics Data System (ADS)

Effects of post-annealing on the depth profile of oxygen content of indium tin oxide (ITO) films on glass substrates have been investigated. Absolute oxygen content of the films was estimated by a high-energy ion beam technique. The electrical properties and the oxygen contents, measured before and after post-annealing in vacuum, have been compared for films deposited under different conditions. Our present results implied that oxygen deficiency at the film surface, induced by post-annealing, might be responsible for the observed improvement of the electrical properties.

Honda, Shinichi; Tsujimoto, Akira; Watamori, Michio; Oura, Kenjiro

1995-10-01

139

Vacuum Technology and Space Simulation  

Microsoft Academic Search

Market: Those involved in vacuum technology and complex vacuum facilities. While specific projects have changed in the 30 years since this book was first published, the need for large complex vacuum facilities has not. And despite new developments in pumping, measurement, and outgassing, this book will remain for many years to come the standard of practical vacuum operation.

D. J. Santeler; D. H. Hokeboer; D. W. Jones; F. Pagano

1993-01-01

140

System Study, Vacuum Sewage Collection.  

National Technical Information Service (NTIS)

An effectiveness/cost comparison was made between gravity sewer systems and vacuum sewer systems for use in Navy advanced bases. The vacuum systems considered were single pipe system where vacuum toilets are connected directly to a vacuum sewer while the ...

R. Waller C. W. Mallory

1971-01-01

141

R&D ERL: Vacuum  

Microsoft Academic Search

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

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

2010-01-01

142

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

143

Effect of short annealing times on the magnetoelectronic properties of Co/Pd-based pseudo-spin-valves.  

PubMed

We investigated the effects of short annealing times on the magnetoelectronic properties of pseudo-spin-valves (PSV) with perpendicular magnetic anisotropy based on Co/Pd multilayers using a contact hot plate. In order to study the time scale at which the degradation of film properties occurs for possible application in perpendicular MgO-based magnetic tunnel junctions (MTJ), the results were compared against our previous study of Co/Pd PSV based on vacuum annealing. With contact annealing for up to 90 s, no significant changes to the current-in-plane giant magnetoresistance (CIP-GMR), interlayer coupling, sheet resistance and layer coercivities were observed for up to 200 degrees C. At 350 degrees C, a 39 to 46% decrease in CIP-GMR was observed for annealing times of 30 to 90 s, respectively, slightly lower than that observed for vacuum annealing at 230 degrees C for 1 h. Similar results were also obtained for interlayer coupling, sheet resistance and layer coercivities, indicating that short annealing times allow for reduced interlayer diffusion at higher temperatures. However, it is clear that significant degradation of GMR performance occurs at 350 degrees C and above even for annealing times as short as 30 s, indicating the potential difficulty of realizing Co/Pd-based perpendicular MgO-MTJ. PMID:21449449

Tahmasebi, Taiebeh; Law, Randall; Sbiaa, Rachid; Piramanayagam, S N; Chong, Tow Chong

2011-03-01

144

High temperature annealing of micrometric Zn 2SiO 4:Mn phosphor powders in fluidized bed  

Microsoft Academic Search

Micrometric Zn1.8Mn0.2SiO4 phosphor powders prepared by spray pyrolysis have been annealed between 900 and 1200C under ambient air atmosphere to investigate their luminescence properties. Two original gassolid fluidization processes have been tested in order to limit sintering phenomena, and the post-treated products have been compared with those annealed using a conventional process in crucible. The crystallinity, the size distribution, the

Shila Alavi; Jeannette Dexpert-Ghys; Brigitte Caussat

2008-01-01

145

Annealing effect on the magnetic properties of evaporated CoCr thin films  

NASA Astrophysics Data System (ADS)

Series of CoxCr1-x thin films have been evaporated under vacuum onto monocrystalline silicon substrate, x being atomic percent of cobalt. The thickness ranges from 17 to 220 nm, values measured by Rutherford backscattering spectrometry. The samples have been annealed under vacuum for one hour at 700 C. The as deposited films show a hexagonal close packed (hcp) structure while the annealed films show both hexagonal close packed and face centered cubic (fcc) structures. While the as deposited films are under a compressive stress, the annealed films, on the contrary, are under a tensile stress. The hysteresis loops present the same features for the as deposited and annealed films concerning the in-plane and out-of-plane anisotropies. Nevertheless, the coercive field is strongly improved for the annealed films. Moreover, these latter films present very high values of the squareness. A squareness value up to 0.96 has been measured. All these results and others are analyzed and discussed.

Kharmouche, Ahmed; Djouada, Intissar; Schmerber, Guy

2013-08-01

146

Hypervelocity impact phenomena  

SciTech Connect

There is a need to determine the equations of state of materials in regimes of extreme high pressures, temperatures and strain rates that are not attainable on current two-stage light-gas guns. Understanding high-pressure material behavior is crucial to address the physical processes associated with a variety of hypervelocity impact events related to space sciences-orbital-debris impact, debris-shield designs, high-speed plasma propagation, and impact lethality applications. At very high impact velocities material properties will be dominated by phase-changes, such as melting or vaporization, which cannot be achieved at lower impact velocities. Development of well-controlled and repeatable hypervelocity launch capabilities is the first step necessary to improve our understanding of material behavior at extreme pressures and temperatures not currently available using conventional two-stage light-gas gun techniques. In this paper, techniques that have been used to extend both the launch capabilities of a two-stage light gas gun to 16 km/s, and their use to determine the material properties at pressures and temperature states higher than those ever obtained in the laboratory are summarized. The newly developed hypervelocity launcher (HVL) can launch intact (macroscopic dimensions) plates to 16 km/s. Time-resolved interferometric techniques have been used to determine shock-loading/release characteristics of materials impacted by such fliers as well as shock-induced vaporization phenomena in fully vaporized states. High-speed photography or radiography has been used to evaluate the debris propagation characteristics resulting from disc impact of thin bumper sheets at hypervelocities in excess of 10 km/s using the HVL. Examples of these experiments are provided in this paper.

Chhabildas, L.C.

1995-07-01

147

Material processing with vacuum  

NASA Astrophysics Data System (ADS)

The use of controlled atmosphere, especially vacuum, is the integral part of much the materials processing effort involving special materials. The underlying reasons that warrant the presence of vacuum along with high temperatures in these processing schemes are rooted in the thermodynamic properties of the materials particularly in relation to their interaction with gases and other interstitials. Apart from this pressure is also a highly usable process parameter that can be tailored to establish the desired heterogeneous equilibrium, in turn determined by the material to be produced or process to be executed. The range and depth of vacuum metallurgy or vacuum materials processing is vast. The present paper covers a selection of materials processing activities that have been carried out in the Materials Group, BARC involving production of materials, their processing and also basic property determination. A range of vacuum and furnace systems have been used and the practice of designing the process from fundamentals and executing through various batch sizes, and the solution of issues involved are all covered.

Krishnamurthy, N.; Suri, A. K.

2008-05-01

148

ISABELLE vacuum systems  

SciTech Connect

The Intersecting Storage Accelerator (ISABELLE) consists of two rings having a circumference of 3.8 km each. In these rings superconducting magnets, held at 4 K, bend and focus the proton beam which is accelerated up to 400 GeV. Due to very different pressure requirements, ISABELLE has two completely independent vacuum systems. One, which operates at 1 x 10/sup -11/ Torr, provides a very clean environment for the circulating proton beam. Here only ion and titanium sublimation pumps are used to provide the vacuum. The other system maintains superconducting magnet vessels at a pressure below 1 x 10/sup -4/ Torr, since at this pressure the gas conduction becomes negligible. In this so-called insulating vacuum system, turbomolecular pumps pump the inadvertent small helium leaks. Other gases are cryocondensed on the cold surfaces of the cryogenic system. The basic element of ISABELLE known as Full Cell containing 45 meters of beam tube, 8 pumping stations, 8 superconducting magnets and complete instrumentation has been constructed, leak checked and tested. All design parameters have been achieved in both vacuum systems. The two vacuum systems are described with particular emphasis on the influence of superconducting magnets in the selection of materials and UHV components.

Halama, H J

1980-01-01

149

In situ laser annealing system for real-time surface kinetic analysis  

NASA Astrophysics Data System (ADS)

For real-time analysis during thermal annealing, a continuous wave CO2 infrared laser was coupled to a surface analysis system equipped for x-ray photoelectron spectroscopy (XPS) and ion scattering spectroscopy (ISS). The laser beam was directed into the vacuum chamber through a ZnSe window to the back side of the sample. With 10 W laser output, the sample temperature reached 563 K. The chamber remained below 10-8 Torr during annealing and allowed XPS and ISS data to be gathered as a function of time at selected temperatures. As a test example, real time Cu2O reduction at 563 K was investigated.

Wang, Q.; Sun, Y.-M.; Zhao, W.; Campagna, J.; White, J. M.

2002-11-01

150

Inhomogeneous superconductivity induced by interstitial Fe deintercalation in oxidizing-agent-annealed and HNO3-treated Fe1+y(Te1-xSex)  

NASA Astrophysics Data System (ADS)

We have systematically investigated the effect of annealing on the superconductivity of the iron chalcogenide Fe1+y(Te1-xSex). The atmospheres used for annealing include O2, N2, I2 vapor, air and vacuum. We observed that annealing in O2, I2 and air could enhance the superconductivity of underdoped samples, consistent with the results reported in the literature. Interestingly, we found that annealing in N2 also leads to a superconductivity enhancement, similar to the annealing effects of O2, I2 and air. However, vacuum annealing does not enhance the superconductivity, which indicates that the enhanced superconductivity in O2-, N2- , I2- and air-annealed samples is not due to improved homogeneity. In addition, we treated underdoped samples with nitric acid, which is found to enhance the superconductivity as well. Our analyses of these results support the argument that the superconductivity enhancement, caused either by annealing or nitric acid treatment, originates from the variation of interstitial Fe. The interstitial Fe, which is destructive to superconducting pairing, can be reduced by annealing in oxidation agents or nitric acid treatment. We also find that although N2-, O2- and air-annealed samples exhibit strong superconducting diamagnetism with -4?? 1 (?, dc magnetic susceptibility) for some samples, their actual superconducting volume fraction probed by specific heat is low, ranging from 10% to 30% for 0.09 < x < 0.3, indicating that the superconductivity suppression remains significant even in annealed samples. The strong diamagnetism is associated with the superconducting shielding effect on the non-superconducting phase. We have also established the phase diagram of the annealed samples and compared it with that of the as-grown samples. The effect of annealing on the interplay between magnetism and superconductivity is discussed.

Hu, J.; Wang, G. C.; Qian, B.; Mao, Z. Q.

2012-08-01

151

THE ANNEALING OF IODIDE HAFNIUM  

Microsoft Academic Search

The effects of heat treatments on the hardness of cold rolled hafnium is ; described. Equations and curves for predicting hardness after heat treatments of ; varying periods of time at temperatures of 750, 800, and 850 deg C for cold ; reductions up to 25% in 5% increments are presented. Other curves are provided ; that estimate annealing times

1962-01-01

152

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

153

Mathematical methods of studying physical phenomena  

NASA Astrophysics Data System (ADS)

In recent decades, substantial theoretical and experimental progress was achieved in understanding the quantum nature of physical phenomena that serves as the foundation of present and future quantum technologies. Quantum correlations like the entanglement of the states of composite systems, the phenomenon of quantum discord, which captures other aspects of quantum correlations, quantum contextuality and, connected with these phenomena, uncertainty relations for conjugate variables and entropies, like Shannon and Rnyi entropies, and the inequalities for spin states, like Bell inequalities, reflect the recently understood quantum properties of micro and macro systems. The mathematical methods needed to describe all quantum phenomena mentioned above were also the subject of intense studies in the end of the last, and beginning of the new, century. In this section of CAMOP 'Mathematical Methods of Studying Physical Phenomena' new results and new trends in the rapidly developing domain of quantum (and classical) physics are presented. Among the particular topics under discussion there are some reviews on the problems of dynamical invariants and their relations with symmetries of the physical systems. In fact, this is a very old problem of both classical and quantum systems, e.g. the systems of parametric oscillators with time-dependent parameters, like Ermakov systems, which have specific constants of motion depending linearly or quadratically on the oscillator positions and momenta. Such dynamical invariants play an important role in studying the dynamical Casimir effect, the essence of the effect being the creation of photons from the vacuum in a cavity with moving boundaries due to the presence of purely quantum fluctuations of the electromagnetic field in the vacuum. It is remarkable that this effect was recently observed experimentally. The other new direction in developing the mathematical approach in physics is quantum tomography that provides a new vision of quantum states. In the tomographic picture of quantum mechanics, the states are identified with fair conditional probability distributions, which contain the same information on the states as the wave function or the density matrix. The mathematical methods of the tomographic approach are based on studying the star-product (associative product) quantization scheme. The tomographic star-product technique provides an additional understanding of the associative product, which is connected with the existence of specific pairs of operators called quantizers and dequantizers. These operators code information on the kernels of all the star-product schemes, including the traditional phase-space Weyl-Wigner-Moyal picture describing the quantum-system evolution. The new equation to find quantizers, if the kernel of the star product of functions is given, is presented in this CAMOP section. For studying classical systems, the mathematical methods developed in quantum mechanics can also be used. The case of paraxial-radiation beams propagating in waveguides is a known example of describing a purely classical phenomenon by means of quantum-like equations. Thus, some quantum phenomenon like the entanglement can be mimicked by the properties of classical beams, for example, Gaussian modes. The mathematical structures and relations to the symplectic symmetry group are analogous for both classical and quantum phenomena. Such analogies of the mathematical classical and quantum methods used in research on quantum-like communication channels provide new tools for constructing a theoretical basis of the new information-transmission technologies. The conventional quantum mechanics and its relation to classical mechanics contain mathematical recipes of the correspondence principle and quantization rules. Attempts to find rules for deriving the quantum-mechanical formalism starting from the classical field theory, taking into account the influence of classical fluctuations of the field, is considered in these papers. The methods to solve quantum equations and formulate the boundary co

Man'ko, Margarita A.

2013-03-01

154

Vacuum-assisted delivery.  

PubMed

The literature seems to allow certain general conclusions regarding the choice of instrument for assisted vaginal delivery. Both forceps and vacuum extraction offer certain advantages and drawbacks. Forceps are more difficult to apply, more prone to potentially significant facial injuries, require generally better maternal analgesia, and are associated with increased maternal soft tissue trauma. Vacuum extractors in general are easier to apply, are more likely to result in scalp trauma, and may be associated with increased rates of intracranial trauma. It seems likely that factors particular to each patient may play a significant role in the genesis of delivery associated with maternal and neonatal morbidity. Because of the ease of application, vacuum extractors may be used potentially in circumstances in which forceps assistance would not be attempted, allowing an operator of average experience to perform rotational deliveries. The use of vacuum extraction does appear to decrease the incidence of cesarean section in delivery populations. Given the apparent association between difficult assisted deliveries and increased neonatal morbidity, it is incumbent on the operator to attempt delivery only when vaginal delivery seems to be a safe option. Furthermore, the operator in such circumstances must be willing to reassess the attempt if initial attempts are not met with success. The minimal rates of significant intracranial injury associated with vacuum extraction in randomized studies of the method demonstrate the relative safety of the vacuum extraction when used judiciously. The ultimate choice of the route of delivery and method of assisted delivery should reflect a consideration of the fetal station, presentation, and maternal and fetal circumstances. It is hoped that further investigations in this area may clarify some of the issues discussed in this article. PMID:8665766

Williams, M C

1995-12-01

155

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

156

Vacuum pseudoscalar susceptibility  

SciTech Connect

We derive a novel model-independent result for the pion susceptibility in QCD via the isovector-pseudoscalar vacuum polarization. In the neighbourhood of the chiral limit, the pion susceptibility can be expressed as a sum of two independent terms. The first expresses the pion-pole contribution. The second is identical to the vacuum chiral susceptibility, which describes the response of QCD's ground state to a fluctuation in the current-quark mass. In this result one finds a straightforward explanation of a mismatch between extant estimates of the pion susceptibility.

Chang Lei [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Liu Yuxin [Department of Physics, Peking University, Beijing 100871 (China); State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000 (China); Roberts, Craig D. [Department of Physics, Peking University, Beijing 100871 (China); Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Shi Yuanmei [Department of Physics, Nanjing Xiaozhuang College, Nanjing 211171 (China); Sun Weimin; Zong Hongshi [Department of Physics, Nanjing University, Nanjing 210093 (China); Joint Center for Particle, Nuclear Physics and Cosmology, Nanjing 210093 (China)

2010-03-15

157

Vacuum driven accelerated expansion  

NASA Astrophysics Data System (ADS)

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 the language of Schwinger's proper time and the Seeley-DeWitt heat kernel expansion, in the background of the Friedmann-Robertson-Walker geometry.

Broda, B.; Bronowski, P.; Ostrowski, M.; Szanecki, M.

2008-11-01

158

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

159

Quantum Vacuum Pathway Theory  

Microsoft Academic Search

It is theorized that the quantum vacuum is a random electromagnetic field that permeates the universe. It will be shown that acceleration between a quark and a random electromagnetic energy field is an analog of the reaction between a charge moving at constant velocity with respect to an organized electromagnetic field. The difference is that with a quark any natural

Eric John Habegger

2005-01-01

160

Vacuum Kundt waves  

NASA Astrophysics Data System (ADS)

We discuss the invariant classification of vacuum Kundt waves using the Cartan-Karlhede algorithm and determine the upper bound on the number of iterations of the Karlhede algorithm to classify the vacuum Kundt waves (Collins (1991 Class. Quantum Grav. 8 1859-69), Machado Ramos (1996 Class. Quantum Grav. 13 1589)). By choosing a particular coordinate system we partially construct the canonical coframe used in the classification to study the functional dependence of the invariants arising at each iteration of the algorithm. We provide a new upper bound, q ? 4, and show that this bound is sharp by analyzing the subclass of Kundt waves with invariant count beginning with (0, 1,) to show that the class with invariant count (0, 1, 3, 4, 4) exists. This class of vacuum Kundt waves is shown to be unique as the only set of metrics requiring the fourth covariant derivatives of the curvature. We conclude with an invariant classification of the vacuum Kundt waves using a suite of invariants.

McNutt, David; Milson, Robert; Coley, Alan

2013-03-01

161

Electrospray deposition in vacuum  

Microsoft Academic Search

We have used the established technique of electrospray in developing a portable vacuum electrospray system which can deposit, in vacuo, dissolved molecules onto a sample which may then be analysed by UHV techniques. As an initial test of the system we have analysed silicon samples with an electrosprayed layer of poly(ethylene) oxide (PEO) using atomic force microscopy (AFM). The polymer

Janine C. Swarbrick; J. Ben Taylor; James N. O'Shea

2006-01-01

162

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

163

Langmuir vacuum and superconductivity  

NASA Astrophysics Data System (ADS)

It is shown that, in the "jelly" model of cold electron-ion plasma, the interaction between electrons and the quantum electromagnetic vacuum of Langmuir waves involves plasma superconductivity with an energy gap proportional to the energy of the Langmuir quantum.

Veklenko, B. A.

2012-06-01

164

Vacuum configurations for superstrings  

Microsoft Academic Search

We study candidate vacuum configurations in ten-dimensional O(32) and E8 E8 supergravity and superstring theory that have unbroken N = 1 supersymmetry in four dimensions. This condition permits only a few possibilities, all of which have vanishing cosmological constant. In the E8 E8 case, one of these possibilities leads to a model that in four dimensions has an

P. Candelas; Gary T. Horowitz; Andrew Strominger; Edward Witten

1985-01-01

165

Large Rotary Vacuum Seal  

Microsoft Academic Search

A seal is described which permits rotation of large circular sections or ; ports in the walls of a vacuum chamber. The seal is an unlubricated Tec-Ring (a ; Teflon O-ring with a core of rubber), and the friction is low even at large ; diameters. The behavior of such a seal is compared with that of a lubricated ;

D. E. Armstrong; Normand Blais

1963-01-01

166

Vacuum in Multicolor QCD.  

National Technical Information Service (NTIS)

It is assumed that among asymptotic solutions to the Makeenko-Migdal equation of the form exp(-aA - bL) (A = area, L = perimeter, A and L are large) there is also the solution which has asymptotic freedom at small distances. It is then shown that vacuum i...

P. Olesen

1980-01-01

167

Type D Vacuum Metrics  

Microsoft Academic Search

Using the Newman-Penrose formalism, the vacuum field equations are solved for Petrov type D. An exhaustive set of ten metrics is obtained, including among them a new rotating solution closely related to the Ehlers-Kundt ``C'' metric. They all possess at least two Killing vectors and depend only on a small number of arbitrary constants.

William Kinnersley

1969-01-01

168

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

169

Cryogenic vacuum pump design  

Microsoft Academic Search

This paper is a review of the problems and tradeoffs involved in cryogenic vacuum pump analysis, design and manufacture. Particular attention is paid to the several issues unique to cryopumps, e.g., radiation loading, adsorption of noncondensible gases, and regeneration. A general algorithm for cryopump design is also proposed.

A. J. Bartlett; P. A. Lessard

1984-01-01

170

The LHC Vacuum System  

Microsoft Academic Search

The Large Hadron Collider (LHC) at CERN, involves two proton storage rings with colliding beams of 7 TeV. The machine will be housed in the existing LEP tunnel and requires 16 m long superconducting b ending magnets. The vacuum chamber will be the inner wall of the cryostat and hence at the temperature of the magnet cold bore, i.e. at

Oswald Grbner

1998-01-01

171

Electtra vacuum system  

Microsoft Academic Search

Elettra is a third-generation synchrotron light source which is being built especially for the use of high brilliance radiation from insertion devices and bending magnets. The UHV conditions in a storage ring lead to a longer beam lifetime-one of the most important criterion. The Elettra vacuum system presents some peculiarities which cannot be found in any already existing machine. The

M. Bernardini; F. Daclon; F. Giacuzzo; R. Kersevan; J. Miertusova; F. Pradal

1993-01-01

172

Vacuum insulator coating development  

Microsoft Academic Search

The authors discuss the electrical and mechanical requirements for vacuum insulators in high peak power generators. To increase the lifetime of these insulators, they have developed a coating called Dendresist. This coating has extended the insulator lifetime on the PITHON, DM2, CASINO, and Double-EAGLE pulsed power generators. They describe its development, and compare its electrical and mechanical strength to that

I. S. Roth; P. S. Sincerny; L. Mandelcorn; M. Mendelsohn; D. Smith; T. G. Engel; L. Schlitt; C. M. Cooke

1997-01-01

173

RF Vacuum Electronics.  

National Technical Information Service (NTIS)

We summarize our second quarter progress and discuss third quarter plans for the development of an edge emitter based vacuum triode with performance goals of 10 microA/micrometer emission current density at less than 250V and which can be modulated at1 GH...

D. Arch J. Holmen P. Bauhahn T. Akinwande T. Ohnstein

1992-01-01

174

Interpreting cosmological vacuum decay  

SciTech Connect

The cosmological vacuum decay scenario recently proposed by Wang and Meng [Classical Quantum Gravity 22, 283 (2005)] is rediscussed. From thermodynamic arguments it is found that the {epsilon} parameter quantifying the vacuum decay rate must be positive in the presence of particle creation. If there is no particle creation, the proper mass of Cold Dark Matter (CDM) particles is necessarily a time-dependent quantity, scaling as m(t)=m{sub o}a(t){sup {epsilon}}. By considering the presence of baryons in the cosmological scenario, it is also shown that their dynamic effect is to alter the transition redshift z{sub *} (the redshift at which the Universe switches from decelerating to accelerating expansion), predicting values of z{sub *} compatible with current estimates based on type Ia supernova. In order to constrain the {omega}{sub m}-{epsilon} plane, a joint statistical analysis involving the current supernovae observations, gas mass fraction measurements in galaxy clusters and CMB data is performed. At 95% c.l. it is found that the vacuum decay rate parameter lies on the interval {epsilon}=0.06{+-}0.10. The possibility of a vacuum decay into photons is also analyzed. In this case, the energy density of the radiation fluid scales as {rho}{sub r}={rho}{sub ro}a{sup -4+{epsilon}}, and its temperature evolution law obeys T(t)=T{sub o}a(t){sup {epsilon}}{sup /4-1}.

Alcaniz, J.S.; Lima, J.A.S. [Departamento de Astronomia, Observatorio Nacional, 20921-400 Rio de Janeiro - RJ (Brazil); Instituto de Astronomia, Geofisica e Ciencias Atmosfericas, USP, 05508-900 Sao Paulo, SP (Brazil)

2005-09-15

175

Triggered vacuum gaps  

Microsoft Academic Search

Characteristics of a sealed vacuum gap are described and the difficulties encountered in applying this gap as an overvoltage protection device are discussed. It is shown how these difficulties can be ameliorated by the use of gas-free electrode materials and by triggering the gap when breakdown is required. Several methods of triggering are discussed and some practical triggering devices are

J. M. Lafferty

1966-01-01

176

Formation of Si/SiC multilayers by low-energy ion implantation and thermal annealing  

NASA Astrophysics Data System (ADS)

Si/SiC multilayer systems for XUV reflection optics with a periodicity of 10-20 nm were produced by sequential deposition of Si and implantation of 1 keV CHx+ ions. Only about 3% of the implanted carbon was transferred into the SiC, with a thin, 0.5-1 nm, buried SiC layer being formed. We investigated the effect of thermal annealing on further completion of the carbide layer. For the annealing we used a vacuum furnace, a rapid thermal annealing system in argon atmosphere, and a scanning e-beam, for different temperatures, heating rates, and annealing durations. Annealing to a temperature as low as 600 C resulted in the formation of a 4.5 nm smooth, amorphous carbide layer in the carbon-implanted region. However, annealing at a higher temperature, 1000 C, lead to the formation of a rough poly-crystalline carbide layer. The multilayers were characterized by grazing incidence X-ray reflectometry and cross section TEM.

Dobrovolskiy, S.; Yakshin, A. E.; Tichelaar, F. D.; Verhoeven, J.; Louis, E.; Bijkerk, F.

2010-03-01

177

The evolution of the structure and mechanical properties of fullerenelike hydrogenated amorphous carbon films upon annealing  

SciTech Connect

Hydrogenated amorphous carbon films were deposited on Si (100) substrates using dc-pulse plasma chemical vapor deposition. Structurally, the as-deposited carbon films could be considered as nanocomposite thin films with fullerenelike microstructure in diamondlike carbon matrix based on our previous result [Q. Wang et al., Appl. Phys. Lett. 91, 141902 (2007)]. In this paper, the evolution of the structure and the mechanical properties of hydrogenated carbon films with fullerenelike microstructure on the annealing in vacuum was investigated. The fullerenelike hydrogenated carbon films annealed at 500 deg. C showed higher hardness (16.9% harder) and higher elastic recovery (11.2% higher) than the as-deposited films. The friction coefficient of fullerenelike hydrogenated carbon films in air with 40% relative humidity remained constant at about 0.037 when annealed at 600 deg. C. The wear rate of the films decreased sharply when annealed at 200 or 300 deg. C. Structural analysis shows that annealing at 300 deg. C improved tribological properties originated from the volume increase in the fullerenelike microstructure, and further annealing at 600 deg. C improved mechanical properties originated from the transformation of nanosized curved sp{sup 2} to sp{sup 3} clusters.

Wang Qi [Department of Physics, Lanzhou University, Lanzhou 730000 (China); State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); He Deyan [Department of Physics, Lanzhou University, Lanzhou 730000 (China); Wang Chengbing; Wang Zhou; Zhang Junyan [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

2008-08-15

178

Eclipse Phenomena -- a Book Review.  

National Technical Information Service (NTIS)

The document is a review of the book Eclipse Phenomena in Astronomy by F. Link. The author of this book is a Czechoslovakian astronomer who has been associated with both Eastern and Western research in astronomy and space exploration.

G. F. Schilling

1969-01-01

179

ISAC target vacuum system  

SciTech Connect

The Isotope Separator and Accelerator (ISAC) facility at TRIUMF has been in full operation since 1999. The ISAC east and west targets use proton beam from the cyclotron to produce various radioactive isotopes, which are then ionized and extracted. The ions are then passed through the mass separator and selected ions are transferred to the low energy experiments or injected into a radio frequency quadrupole accelerator. The accompanying radioactive contamination from the production of radioactive ions requires a complex vacuum system. The main target vacuum space consists of two semiseparate (primary and secondary) volumes pumped by turbo-molecular pumps. The primary volume uses four pumps while the secondary volume uses two pumps. Two hermetic rotary vane pumps are used as backing pumps. The nominal vacuum in both volumes is about 1.33x10{sup -4} Pa (1.0x10{sup -6} Torr). The pressure is monitored by two cold cathode and two hot filament ion gauges. The cold cathode gauges are used to interlock the system, which is critical during the bake out of the target and beam production. The exhaust gas from the vacuum pumps can be radioactive. Three gas storage tanks (decay tanks) are used for temporary storage of the radioactive exhaust and its controlled release to the atmosphere. Gas-species insensitive membrane gauges are used for monitoring the pressure in the storage tanks. This article describes the details of the ISAC target vacuum system as well as some procedures related to the handling of the exhaust gas with traces of radioactive contamination produced by the targets.

Yosifov, Dimo; Sekachev, Igor [TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, British Columbia V6T 2A3 (Canada)

2006-07-15

180

Vacuum requirements for RHIC  

SciTech Connect

In this note the lifetime due to inelastic scattering of beam and residual gas ions is calculated in units of pressure (Torr). In addition, the transverse emittance growth due to elastic scattering is expressed in units of pressure. The definition of inelastic scattering includes both capture of an electron from a residual gas ion and central nuclear collisions between beam ion and gas atom. Emittance growth via elastic scattering is a simple consequence of multiple Coulomb scattering. Is is important to note that in an accelerator only the density of residual gas atoms is relevant to the machine operation. The measure of this density is the vacuum gauge, where this gauge is calibrated in pressure units at some known temperature T{sub G}. The vacuum unit or pressure is of course temperature dependent, and thus when quoting vacuum requirements for RHIC it is vital to state the temperature at which the pressure is computed. It might be necessary to scale any computed gas density to the pressure appropriate for the measurement with the vacuum gauge. Typically, the vacuum gauge operates at room temperature {approximately}300{degree}K. An explanation on how to rescale pressure as a function of temperature is given in the text. This note assumes the residual gas density in the so-called warm section (300{degree}K) of RHIC to be composed of 90% H{sub 2}, 5% CH{sub 4} and 5% CO. The gas in the cold section (5{degree}K) is assumed to be 100% He. The beam ions are taken to be {sup 197}Au{sup 79+}.

Rhoades-Brown, M.J.; Harrison, M.

1991-12-01

181

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

182

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

183

Preparation and characterization of new window material CdS thin films at low substrate temperature (<300 K) with vacuum deposition  

Microsoft Academic Search

Low-temperature vacuum deposition instead of the commonly used vacuum deposition at high substrate temperatures has been applied to prepare new window material CdS thin films. The structural, optical and electrical properties of vacuum-evaporated CdS thin films were investigated as a function of substrate temperature (100300K) and the post-deposition annealing temperature (at 473, 573 and 673K). It was determined that films

M. Tomakin; M. Altunba?; E. Bacaks?z; ?. Polat

2011-01-01

184

Tritium handling in vacuum systems  

SciTech Connect

This report provides a course in Tritium handling in vacuum systems. Topics presented are: Properties of Tritium; Tritium compatibility of materials; Tritium-compatible vacuum equipment; and Tritium waste treatment.

Gill, J.T. [Monsanto Research Corp., Miamisburg, OH (United States). Mound Facility; Coffin, D.O. [Los Alamos National Lab., NM (United States)

1986-10-01

185

Improvement in the electrical properties of Se- and S-doped hydrogenated amorphous silicon thin films by annealing  

NASA Astrophysics Data System (ADS)

We studied the effect of annealing on the dark and photo conductivity of Se- and S-doped hydrogenated amorphous silicon (a-Si:H) thin films. The films were prepared on corning glass by using conventional plasma-enhanced chemical vapor deposition (PE-CVD). The samples were subsequently annealed in a vacuum (1 10-6Torr) at an annealing temperature of 300 C for an hour. The conductivity was measured in the temperature range of 300-470 K, which exhibited two different transport mechanisms. In the high-temperature range (370-470 K), the conduction was found to be an activated type while in the low-temperature range (less than 370 K), it was observed to follow variable range hopping. Arrhenius plots of the conductivities for S- and Se-doped a-Si:H films revealed that the activation energy was lower after annealing, owing to the removal of the surface defects created during deposition. The characteristic energy, E MN, was lower in the annealed films for both types of dopant concentrations, which suggests a reduction in the number of traps. The photoconductivity was increased by vacuum annealing at 300 C by a factor of more than 10.

Sharma, S. K.; Kim, Deuk Young; Mehra, R. M.

2013-05-01

186

In situ laser annealing system for real-time surface kinetic analysis  

Microsoft Academic Search

For real-time analysis during thermal annealing, a continuous wave CO2 infrared laser was coupled to a surface analysis system equipped for x-ray photoelectron spectroscopy (XPS) and ion scattering spectroscopy (ISS). The laser beam was directed into the vacuum chamber through a ZnSe window to the back side of the sample. With 10 W laser output, the sample temperature reached 563

Q. Wang; Y.-M. Sun; W. Zhao; J. Campagna; J. M. White

2002-01-01

187

Effect of high temperature annealing on optical and thermal properties of CVD diamond  

Microsoft Academic Search

Structural changes in diamond films of different qualities caused by annealing in vacuum up to 1600C have been studied by IR and UV-visible optical absorption, Raman and photoluminescence spectroscopy. An internal degradation of the diamond films and a strong optical absorption enhancement in the whole UV-vis-IR range take place at T>1300C, and correlate with the loss of bonded hydrogen. At

A. V. Khomich; V. G. Ralchenko; A. V. Vlasov; R. A. Khmelnitskiy; I. I. Vlasov; V. I. Konov

2001-01-01

188

Influence of Impurities on Carrier Removal and Annealing in Neutron-Irradiated Silicon  

Microsoft Academic Search

The influence of impurities on carrier removal and annealing has been investigated in neutron-irradiated silicon in the resistivity range from 0.5 to 50 ohm-cm. Carrier removal rates in n-type material are strongly dependent upon the crystal growth method and are lower in Czochralski-grown (oxygen containing) material than in material grown by the vacuum-float-zone or LOPEX techniques. A slight dependence of

R. F. Bass

1967-01-01

189

Vacuum Mechanisms of Nanoscale Precision  

Microsoft Academic Search

The principles of design of vacuum mechanims of nanoscale precision are presented. Physical basics of the mechanisms nanoscale\\u000a precision are discussed. Vacuum multicoordinate drives and manipulators are also shown.\\u000a \\u000a The analysis of vacuum technological equipment and vacuum research equipment shows that the most strict requirements for the\\u000a object transference are in electron beam micro lithography equipment. For example, electron beam

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

190

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

191

VACUUM OSMOTIC DEHYDRATION OF FRUITS  

Microsoft Academic Search

Vacuum osmotic dehydration leads a special behaviour of mass transfer in fruit-sugar soluion system.Vacuum treatments intensify the capillary flow function and increase water transfer ratio.but have no significant influence on sugar uptake.Fruits such as pineapples which have higher porosity are more suitable to be treated under vacuum during the osmotic dehydration.

Xian Quan Shi; Pedro Fito Maupoey

1993-01-01

192

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); Kelly, Benjamin E. (Tracy, CA)

1980-01-01

193

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

194

Challenges For Vacuum Interrupter Design  

Microsoft Academic Search

Vacuum interrupters form the key component of a medium voltage (MV) vacuum switchgear design. Vacuum interrupter technology is now well established and key manufacturers across the world are routinely producing interrupters for ratings up to 52kVrms. Manufacturers have focused on reducing the cost of interrupter components by adapting to more efficient contact geometry, improved contact materials, finite element modelling for

R. Parashar; A. Baker; A. Sitzia

2006-01-01

195

Influence of post-deposition thermal annealing on the properties of pulsed laser deposited tungsten layers  

NASA Astrophysics Data System (ADS)

Crystalline tungsten oxide thin films are obtained by thermal oxidation of metallic W films, deposited on quartz substrates under vacuum conditions by the pulsed laser deposition (PLD) technique. The as-deposited tungsten films are annealed in air at various temperatures, viz. 673, 873 and 1073 K. X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM) and micro-Raman techniques are employed for the investigation of microstructural characterization of both as-deposited and annealed films. The influence of laser energy and duration of deposition on the microstructural, optical and electrical properties of the films are studied in detail. Among the films investigated, thicker tungsten films (having a thickness of ~500 nm), deposited with laser fluence 4 J cm-2 for 45 min duration and annealed at 873 K, exhibit better physical properties and microstructural features compared to other films.

Lethy, K. J.; Vinod Kumar, R.; Potdar, S.; Detty, A. P.; Bahna, A. H.; Mahadevan Pillai, V. P.

2009-07-01

196

Effects of annealing on the ripple texture and mechanical properties of suspended bilayer graphene  

NASA Astrophysics Data System (ADS)

Periodic ripples of amplitude 15 nm were formed in suspended bilayer graphene after nanoindentation with incremental forces up to 600 nN. The structure was annealed at 620 K in high vacuum and the corresponding modifications in the mechanical properties and surface morphology were investigated. The pre-tension of the pristine sample was found to be 1.46 N m-1 and after annealing it was reduced to 0.72 N m-1. The nanometre-sized ripples induced by mechanical excitation were found to be flattened after annealing. Tailoring surface corrugations in bilayer graphene through nanoindentation and thermal engineering of these ripples thus provides an innovative fabrication route for flexible electronic devices and strain sensors.

Annamalai, M.; Mathew, S.; Jamali, M.; Zhan, D.; Palaniapan, M.

2013-04-01

197

Vacuum chuck having vacuum-nipples wafer support  

US Patent & Trademark Office Database

A vacuum chuck is disclosed which has nipples as support structure and for vacuum delivery. In the preferred embodiment, two types of nipples are used: "plain" nipples which provide only support and vacuum nipples which provide support and deliver vacuum to retain the wafer on the chuck. The contact surface of the plain nipples is made smaller than that of the vacuum nipples. The chuck is secured to a stage using special supports which have limited flexibility in two axis with respect to the chuck, so as to prevent warping the chuck. Special vacuum nipples are disclosed which do not deliver vacuum unless the wafer exerts sufficient predetermined pressure on the nipple. The chuck is designed to hold both 200 mm and 300 mm wafers.

2001-07-10

198

Growth and post-annealing effect on the properties of the new sulfosalt SnSb2S4 thin films  

NASA Astrophysics Data System (ADS)

In this work, the effect of the thermal annealing atmosphere on the structural, optical and electrical properties of the sulfosalt SnSb2S4 films obtained by thermal vacuum evaporation was studied. The samples are annealed at different atmospheres in the temperature range 50-275 C for 1 h. It is observed that SnSb2S4 films exhibit a dramatic change in their electrical properties at transition temperatures of about 150 C, 170 C and 200 C after an annealing process under air, nitrogen and vacuum atmospheres, respectively. The electrical resistivity measurements suggest that obtained films show semiconducting behavior with resistivities between 10 and 100 ? cm; the annealed films present rather lower resistivities between 10-2 and 10-3 ? cm and exhibit obvious p+-type semiconductor behavior with a dominant crystalline component.

Gassoumi, A.; Kanzari, M.

2011-10-01

199

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

200

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

201

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

202

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

203

Dry vacuum pumps  

NASA Astrophysics Data System (ADS)

For decades and for ultimate pressure below 1 mbar, oil-sealed Rotary Vane Pumps have been the most popular solution for a wide range of vacuum applications. In the late 80ies, Semiconductor Industry has initiated the development of the first dry roughing pumps. Today SC applications are only using dry pumps and dry pumping packages. Since that time, pumps manufacturers have developed dry vacuum pumps technologies in order to make them attractive for other applications. The trend to replace lubricated pumps by dry pumps is now spreading over many other market segments. For the Semiconductor Industry, it has been quite easy to understand the benefits of dry pumps, in terms of Cost of Ownership, process contamination and up-time. In this paper, Technology of Dry pumps, its application in R&D/industries, merits over conventional pumps and future growth scope will be discussed.

Sibuet, R.

2008-05-01

204

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

205

An automated vacuum system  

SciTech Connect

Software tools available with the Ground Test Accelerator (GTA) control system provide the capability to express a control problem as a finite state machine. System states and transitions are expressed in terms of accelerator parameters and actions are taken based on state transitions. This is particularly useful for sequencing operations which are modal in nature or are unwieldy when implemented with conventional programming. State diagrams are automatically translated into code which is executed by the control system. These tools have been applied to the vacuum system for the GTA accelerator to implement automatic sequencing of operations. With a single request, the operator may initiate a complete pump-down sequence. He can monitor the progress and is notified if an anomaly occurs requiring intervention. The operator is not required to have detailed knowledge of the vacuum system and is protected from taking inappropriate actions. 1 ref., 6 figs.

Atkins, W.H. (Oak Ridge National Lab., TN (USA)); Vaughn, G.D. (Los Alamos National Lab., NM (USA)); Bridgman, C. (Grumman Corp., Bethpage, NY (USA))

1991-01-01

206

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

207

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

PubMed

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. E 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. PMID:23004900

Hasegawa, M

2012-05-22

208

Vacuum actuated gas delivery  

Microsoft Academic Search

The new Vacuum Actuated Cylinder (VACTM) gas source provides sub-atmospheric pressure delivery of the metal fluorides commonly used as dopants for ion implant. The VAC gas source is a mechanical system based on an embedded pressure control device located inside the cylinder. A pre-set sub-atmospheric pressure must be achieved in the delivery manifold before flow is permitted from the cylinder.

W. K. Olander; M. Donatucci; J. Mayer; L. Wang

2000-01-01

209

LHC vacuum system  

Microsoft Academic Search

The Large Hadron Collider (LHC) project, now in the advanced construction phase at CERN, comprises two proton storage rings with colliding beams of 7-TeV energy. The machine is housed in the existing LEP tunnel with a circumference of 26.7 km and requires a bending magnetic field of 8.4 T with 14-m long superconducting magnets. The beam vacuum chambers comprise the

Oswald Grbner

1999-01-01

210

The LHC vacuum system  

Microsoft Academic Search

The Large Hadron Collider (LHC) at CERN, involves two proton storage rings with colliding beams of 7 TeV. The machine will be housed in the existing LEP tunnel and requires 16 m long superconducting bending magnets. The vacuum chamber will be the inner wall of the cryostat and hence at the temperature of the magnet cold bore, i.e. at 1.9

O. Grbner

1997-01-01

211

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

212

Effect of annealing atmosphere on the contact resistivity, superconductivity, and phase transformation in the Al\\/BiSrCaCuO system  

Microsoft Academic Search

This paper reports on the contact resistivity, superconductivity, and phase transformation in the Al\\/BiSrCaCuO(BSCCO) system annealed in air, argon, and vacuum, respectively. The BSCCO films were deposited by dc sputtering on MgO substrates. For the Al\\/BSCCO films, capped with gold and annealed at 750° C in air, the contact resistivity of 7 10⁻⁷ Ω-cm² at 77 K can be

W. T. Lin; H. P. Kao; Y. K. Fang; F. M. Pan

1991-01-01

213

Understand vacuum-system fundamentals  

SciTech Connect

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 performance or cutpoint; vacuum column top temperature and heat balance; light vacuum gas-oil (LVGO) pumparound entrainment to the ejector system; cooling-water temperature; motive steam pressure; non-condensible loading, either air leakage or cracked light-end hydrocarbons; condensible hydrocarbons; intercondenser or aftercondenser fouling ejector internal erosion or product build-up; and system vent back pressure. The paper discusses gas-oil yields; ejector-system fundamentals; condensers; vacuum-system troubleshooting; process operations; and a case study of deepcut operations.

Martin, G.R. (Process Consulting Services, Grapevine, TX (United States)); Lines, J.R. (Graham Manufacturing Co., Inc., Batavia, NY (United States)); Golden, S.W. (Glitsch, Inc., Dallas, TX (United States))

1994-10-01

214

Disorder in Quantum Vacuum: Casimir-Induced Localization of Matter Waves  

SciTech Connect

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.

Moreno, G. A. [IFIBA-Departamento de Fisica, FCEyN, UBA, Ciudad Universitaria, 1428 Buenos Aires (Argentina); Theoretical Division, MS B213, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Messina, R. [Laboratoire Kastler Brossel, case 74, CNRS, ENS, UPMC, Campus Jussieu, F-75252 Paris Cedex 05 (France); SYRTE--Observatoire de Paris 61, avenue de l'Observatoire, F-75014 Paris (France); Dalvit, D. A. R. [Theoretical Division, MS B213, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Lambrecht, A.; Reynaud, S. [Laboratoire Kastler Brossel, case 74, CNRS, ENS, UPMC, Campus Jussieu, F-75252 Paris Cedex 05 (France); Maia Neto, P. A. [Instituto de Fisica, UFRJ, CP 68528, Rio de Janeiro, RJ, 21941-972 (Brazil)

2010-11-19

215

Influence of annealing effects on polyaniline for good microstructural modification.  

PubMed

H(2)SO(4) doped polyaniline (PANI) has synthesized by chemical oxidation method. The prepared Polyaniline were annealed at 150C, 200C and 250C for 30min in vacuum. Crystal size, percentage of crystallinity, total percentage of crystallinity properties of untreated and heat treated PANI samples were studied by using X-ray diffraction pattern. The molecular structure of untreated and heat treated samples were examined by using Fourier transform infrared spectrophotometer. UV study shows ?-?* transition of untreated and heat treated of polyaniline were found at 328 and 636nm. The peak at 636nm reveals the extension of conjugated polymer. Thermal properties of untreated and heat treated PANI sample measured by using thermo gravimetric analysis and differential scanning calorimetric spectroscopy. PMID:23378673

Begum, A Nishara; Dhachanamoorthi, N; Saravanan, M E Raja; Jayamurugan, P; Manoharan, D; Ponnuswamy, V

2013-02-01

216

Effect of thermal annealing of lead oxide film  

NASA Astrophysics Data System (ADS)

Oxygen partial pressure in a growth process of lead oxide determines chemical and physical properties as well as crystalline structure. In order to supply oxygen, two ring-shape suppliers have been installed in a growth chamber. Films have been deposited using vacuum thermal evaporation from a raw material of yellow lead oxide powder (5N). Growth rate is controlled to be about 400 /s, and film thickness more than 50 ?m has been achieved. After deposition, the film is annealed at various temperatures under an oxygen atmosphere. In this study, an optimum growth condition for a good X-ray detector has been achieved by fine control of oxygen flow-rate and by thermal treatment. An electrical resistivity of 4.51012 ? cm is measured, and is comparable with the best data of PbO.

Hwang, Ohhyeon; Kim, Sangsu; Suh, Jonghee; Cho, Shinhang; Kim, Kihyun; Hong, Jinki; Kim, Sunung

2011-05-01

217

Experimental signature of programmable quantum annealing  

NASA Astrophysics Data System (ADS)

Quantum annealing is a general strategy for solving difficult optimization problems with the aid of quantum adiabatic evolution. Both analytical and numerical evidence suggests that under idealized, closed system conditions, quantum annealing can outperform classical thermalization-based algorithms such as simulated annealing. Current engineered quantum annealing devices have a decoherence timescale which is orders of magnitude shorter than the adiabatic evolution time. Do they effectively perform classical thermalization when coupled to a decohering thermal environment? Here we present an experimental signature which is consistent with quantum annealing, and at the same time inconsistent with classical thermalization. Our experiment uses groups of eight superconducting flux qubits with programmable spin-spin couplings, embedded on a commercially available chip with >100 functional qubits. This suggests that programmable quantum devices, scalable with current superconducting technology, implement quantum annealing with a surprising robustness against noise and imperfections.

Boixo, Sergio; Albash, Tameem; Spedalieri, Federico M.; Chancellor, Nicholas; Lidar, Daniel A.

2013-06-01

218

SiGe nanorings by ultrahigh vacuum chemical vapor deposition  

NASA Astrophysics Data System (ADS)

Formation of SiGe nanorings from Si capped Si0.1Ge0.9 quantum dots (QDs) grown at 500 C by ultrahigh vacuum chemical vapor deposition was investigated. SiGe nanorings have average diameter, width, and depth of 185, 30, and 9 nm, respectively. Based on both Raman and x-ray diffraction results, the formation of SiGe nanorings can be attributed to Ge outdiffusion from central SiGe QDs during in situ annealing. Moreover, the depth of SiGe nanorings can be controlled by Si cap thickness. The Si cap is essential for nanorings formation.

Lee, C.-H.; Shen, Y.-Y.; Liu, C. W.; Lee, S. W.; Lin, B.-H.; Hsu, C.-H.

2009-04-01

219

Hierarchical Annealing for Synthesis of Binary Images  

Microsoft Academic Search

This paper introduces a hierarchical annealing algorithm which addresses the very large computational costs associated with\\u000a simulated annealing for the synthesis of binary images. In real-world examples, the large configuration space of such models\\u000a has led to the disappointing performance of annealing approaches. Our method essentially approaches different natural scales\\u000a in the image separately and in a hierarchical manner. We

Simon K. Alexander; Paul Fieguth; Marios A. Ioannidis; Edward R. Vrscay

2009-01-01

220

Semantic search via concept annealing  

NASA Astrophysics Data System (ADS)

Annealing, in metallurgy and materials science, is a heat treatment wherein the microstructure of a material is altered, causing changes in its properties such as strength and hardness. We define concept annealing as a lexical, syntactic, and semantic expansion capability (the removal of defects and the internal stresses that cause term- and phrase-based search failure) coupled with a directed contraction capability (semantically-related terms, queries, and concepts nucleate and grow to replace those originally deformed by internal stresses). These two capabilities are tied together in a control loop mediated by the information retrieval precision and recall metrics coupled with intuition provided by the operator. The specific representations developed have been targeted at facilitating highly efficient and effective semantic indexing and searching. This new generation of Find capability enables additional processing (i.e. all-source tracking, relationship extraction, and total system resource management) at rates, precisions, and accuracies previously considered infeasible. In a recent experiment, an order magnitude reduction in time to actionable intelligence and nearly three orderss magnitude reduction in false alarm rate was achieved.

Dunkelberger, Kirk A.

2007-04-01

221

Discovery potential for new phenomena  

SciTech Connect

The authors examine the ability of future facilities to discover and interpret non-supersymmetric new phenomena. The authors first explore explicit manifestations of new physics, including extended gauge sectors, leptoquarks, exotic fermions, and technicolor models. They then take a more general approach where new physics only reveals itself through the existence of effective interactions at lower energy scales.

Godfrey, S. [Carleton Univ., Ottawa, Ontario (Canada). Ottawa Carleton Inst. for Physics; Hewett, J.L. [Stanford Linear Accelerator Center, Menlo Park, CA (United States); Price, L.E. [Argonne National Lab., IL (United States). High Energy Physics Div.

1997-03-01

222

Electromechanical phenomena in semiconductor nanostructures  

Microsoft Academic Search

Electromechanical phenomena in semiconductors are still poorly studied from a fundamental and an applied science perspective, even though significant strides have been made in the last decade or so. Indeed, most current electromechanical devices are based on ferroelectric oxides. Yet, the importance of the effect in certain semiconductors is being increasingly recognized. For instance, the magnitude of the electric field

L. C. Lew Yan Voon; M. Willatzen

2011-01-01

223

Underwater explosions and cavitation phenomena  

Microsoft Academic Search

Some aspects of underwater explosions and cavitation phenomena have been studied by using a thermodynamic equation of state for water and a one-dimensional Lagrangian hydrocode. The study showed that surface cavitation is caused by the main blast wave and a bubble pulse from rebound of a release wave moving toward the center of the exploding bubble. Gravity has little effect

Kamegai

1979-01-01

224

Visualizing Chemical Phenomena in Microdroplets  

ERIC Educational Resources Information Center

Phenomena that occur in microdroplets are described to the undergraduate chemistry community. Droplets having a diameter in the micrometer range can have unique and interesting properties, which arise because of their small size and, especially, their high surface area-to-volume ratio. Students are generally unfamiliar with the characteristics of

Lee, Sunghee; Wiener, Joseph

2011-01-01

225

Visualizing Chemical Phenomena in Microdroplets  

ERIC Educational Resources Information Center

|Phenomena that occur in microdroplets are described to the undergraduate chemistry community. Droplets having a diameter in the micrometer range can have unique and interesting properties, which arise because of their small size and, especially, their high surface area-to-volume ratio. Students are generally unfamiliar with the characteristics of

Lee, Sunghee; Wiener, Joseph

2011-01-01

226

Dust phenomena in processing plasmas  

Microsoft Academic Search

Dust phenomena in processing plasmas are reviewed from the new viewpoint of birth of material in the plasma. The gas-phase growth of particles has been extensively studied for Si4 RF plasmas. The Si particles usually grow through three distinctive stages: an initial growth phase up to about 10 nm, whose size is between size ranges dominated by plasma properties and

Yukio Watanabe

1997-01-01

227

Efcient Rendering of Atmospheric Phenomena  

Microsoft Academic Search

Rendering of atmospheric bodies involves modeling the complex interaction of light throughout the highly scat- tering medium of water and air particles. Scattering by these particles creates many well-known atmospheric optical phenomena including rainbows, halos, the corona, and the glory. Unfortunately, most radiative transport approximations in computer graphics are ill-suited to render complex angularly dependent effects in the presence of

Kirk Riley; David S. Ebert; Martin Kraus; Jerry Tessendorf; Charles Hansen

228

Magnetostrictive Phenomena in Magnetorheological Elastomers  

Microsoft Academic Search

A host of fascinating and useful magnetic phenomena are found in composites containing magnetizable particles in viscoelastic solids. Embedding magnetically soft iron particles in natural rubber produces a class of magnetostrictive composites sometimes termed magnetorheological (MR) elastomers. We have previously shown that these materials can exhibit viscoelastic moduli that increase substantially in an applied magnetic field. In this paper, we

J. M. Ginder; S. M. Clark; W. F. Schlotter; M. E. Nichols

2002-01-01

229

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

230

Thermodynamic constraints on fluctuation phenomena  

Microsoft Academic Search

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

O. J. E. Maroney

2009-01-01

231

Phenomena of flooding with condensation  

Microsoft Academic Search

The penetration of ECC water in the downcomer region of PWRs has recently been the subject of considerable research due to its importance in the safety analysis of a hypothetical LOCA. The difficulties in such analysis lie in the lack of understanding of the basic phenomena of counter-current two-phase flow, complicated also by the condensation effect and the geometry effect

Fan

1979-01-01

232

Theory of dynamic critical phenomena  

Microsoft Academic Search

An introductory review of the central ideas in the modern theory of dynamic critical phenomena is followed by a more detailed account of recent developments in the field. The concepts of the conventional theory, mode-coupling, scaling, universality, and the renormalization group are introduced and are illustrated in the context of a simple example-the phase separation of a symmetric binary fluid.

P. C. Hohenberg; B. I. Halperin

1977-01-01

233

Energetic Deposition in Vacuum  

SciTech Connect

In hoping to improve Niobium deposition on Copper cavity, a vacuum deposition system has been built to test the idea of Nb energetic condensation on copper substrate. The system directly uses microwave power to create the pure Nb plasma, which can be used to extract energetic Nb ion flux to do direct deposition on copper substrate. In this paper, we briefly describe the system, discuss the potential benefit of this technique and report the initial result of Nb plasma creation and Niobium thin film deposition.

G. Wu; L. Phillips; R. Sundelin; T. Goodman

2001-09-01

234

Thermal Stability of RuO2 Thin Films and Effects of Annealing Ambient on Their Reduction Process  

NASA Astrophysics Data System (ADS)

RuO2 films prepared by reactive sputtering were annealed in air and vacuum and the changes of their crystal structure, chemical binding state and resistivity were studied.In air, the RuO2 films maintain a rutile structure below 800C.Crystal grain growth was found above 600C and the minimum resistivity of 46 ?cm was obtained at 800C.The vacuum annealing was conducted with two types of annealing systems, one using an oil diffusion pump and the other using a turbomolecular pump as the main pump.The RuO2 films annealed in the system using the turbomolecular pump were not reduced below 500C, however, the surface of the films was reduced as low as 200C in the system using the oil diffusion pump.The difference in the reduction processes was examined on the basis of the thermodynamics of RuO2 and the influence of reducing residual gases in vacuum.

Kaga, Yukinao; Abe, Yoshio; Sasaki, Midori

1999-06-01

235

Improved Mobility and Transmittance of Room-Temperature-Deposited Amorphous Indium Gallium Zinc Oxide (a-IGZO) Films with Low-Temperature Postfabrication Anneals  

NASA Astrophysics Data System (ADS)

Thin films of amorphous indium gallium zinc oxide with high transmittance were deposited at room temperature onto flexible polymer substrates. Postdeposition anneals were performed at low temperatures in different ambients to obtain films with one of the highest transmittance and mobility values reported in the literature. As-deposited and postanneal films were characterized for electrical and optical properties. Oxygen anneal degraded the electrical performance of the films, which was recovered by succeeding vacuum anneals. A surface scattering model is proposed to determine the relation between mobility and carrier concentrations at low values of carrier concentrations. This model takes into account electronic scattering as a result of grain structure and morphology.

Alford, T. L.; Gadre, M. J.; Vemuri, Rajitha N. P.

2013-04-01

236

RF vacuum electronics  

NASA Astrophysics Data System (ADS)

We summarize our second quarter progress and discuss third quarter plans for the development of an edge emitter based vacuum triode with performance goals of 10 micro-A/micron emission current density at less than 250 V and which can be modulated at 1 GHz for 1 hour. Design and layout of the emitter test mask was completed and fabrication of two process runs of edge emitter diodes were completed. These diode emitters utilize a comb emitter design where high resistivity TaN thin films act as current limiters to prevent edge burnout. Testing of these devices will start during the third quarter. Initial design work on the edge emitter triode was started and is described. Extensive finite element modeling (FEM) and analysis to aid in the triode design took place and is described. Significant process development also took place. Experimental studies of dielectrics such as sputtered SiO2, Si3N4, and PECVD SiO2 and Si3N4 were carried out to understand their leakage characteristics and, thus, to understand their impact on emitter performance. A description of our vacuum test station is also given.

Akinwande, T.; Bauhahn, P.; Ohnstein, T.; Holmen, J.; Arch, D.

1992-04-01

237

Accelerator Vacuum Protection System  

NASA Astrophysics Data System (ADS)

A new and elaborate automatic vacuum protection system using fast acting valve has been installed to avoid accidental venting of accelerator from experimental chamber side. To cover all the beam lines and to reduce the system cost, it has been installed at a common point from where all the seven beam lines originate. The signals are obtained by placing fast response pressure sensing gauges (HV SENSOR) near all the experimental stations. The closing time of the fast valve is 10 milli-second. The fast closing system protects only one vacuum line at a time. At IUAC, we have seven beam lines so one sensor was placed in each of the beam lines near experimental chamber and a multiplexer was incorporated into the fast closing system. At the time of experiment, the sensor of the active beam line is selected through the multiplexer and the Fast closing valve is interlocked with the selected sensor. As soon as the pressure sensor senses the pressure rise beyond a selected pressure, the signal is transferred and the fast valve closes within 10 to 12 millisecond.

Barua, Pradip; Kothari, Ashok; Archunan, M.; Joshi, Rajan

2012-11-01

238

MOLECULAR VACUUM PUMP  

DOEpatents

A multiple molecular vacuum pump capable of producing a vacuum of the order of 10/sup -9/ mm Hg is described. The pump comprises a casing of an aggregate of paired and matched cylindrical plates, a recessed portion on one face of each plate concentrically positioned formed by a radially extending wall and matching the similarly recessed portion of its twin plate of that pair of plates and for all paired and matched plates; a plurality of grooves formed in the radially extending walls of each and all recesses progressing in a spiral manner from their respective starting points out at the periphery of the recess inwardly to the central area; a plurality of rotors rotatably mounted to closely occupy the spaces as presented by the paired and matched recesses between all paired plates; a hollowed drive-shaft perforated at points adjacent to the termini of all spiral grooves; inlet ports at the starting points of all grooves and through all plates at common points to each respectively; and a common outlet passage presented by the hollow portion of the perforated hollowed drive-shaft of the molecular pump. (AEC)

Eckberg, E.E.

1960-09-27

239

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 actuatable to apply the vacuum to lift the object. 1 fig.

Anderson, G.H.

1983-08-09

240

Fabrication and evolution of Cu nanoparticles in Al 2O 3 crystal by ion implantation and annealing at different atmospheres  

NASA Astrophysics Data System (ADS)

Single crystal Al 2O 3 samples were implanted with 45 keV Cu ion implantation at a dose of 1 10 17 ions/cm 2, and then subjected to furnace annealing in vacuum or with a flow of oxygen gas. Various techniques, such as ultraviolet-visible spectroscopy, X-ray diffraction spectroscopy and atomic force microscopy, have been used to investigate formation of Cu NPs and their evolution. Our results clearly show that the evolution of Cu NPs depends strongly on annealing atmosphere in the temperature range up to 600 C. Annealing in vacuum only gives rise to a slight change in the size of Cu NPs. No evidence for oxidization of Cu NPs has been revealed. Remarkable modifications in Cu NPs, including the size increase and the effective transformation into CuO NPs, have been observed for the samples annealed at oxygen atmosphere. The results have been tentatively discussed in combination with the role of oxygen from atmosphere in diffusion of Cu atoms towards the surface and its interactions with Cu NPs during annealing.

Shen, Yanyan; Zhang, Lili; Li, Zhaodong; Zhang, Xiaodong; Zhang, Dacheng; Li, Xu; Wang, Zhuo; Yuan, Bing; Li, Mengkai; Liu, Changlong

2010-04-01

241

Random Transverse Ising Model on Annealed Complex Networks  

NASA Astrophysics Data System (ADS)

In order to shed light on critical phenomena on cuprates, here we propose a stylized model capturing the essential characteristics of the superconducting-insulator transition of a highly dynamical, heterogenous granular material: the Disordered Quantum Tranverse Ising Model (DQTIM) on Annealed Complex Network. We show that when the networks encode for high heterogeneity of the expected degrees described by a power law distribution, the critical temperature for the onset of the supercoducting phase diverges to infinity as the power-law exponent ? of the expected degree distribution is less than 3, i.e. ?< 3. Moreover we investigate the case in which the critical state of the electronic background is triggered by an external parameter g that determines an exponential cutoff in the power law expected degree distribution characterized by an exponent ?. We find that for g = gc the critical temperature for the supercondutor-insulator transition has a maximum if ?> 3 and diverges if ?<3.

Bianconi, Ginestra

2012-02-01

242

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

243

Vacuum-Packaging Technology for IRFPAs  

Microsoft Academic Search

We developed vacuum-packaging equipment and low-cost vacuum packaging technology for IRFPAs. The equipment is versatile and can process packages with various materials and structures. Getters are activated before vacuum packaging, and we can solder caps\\/ceramic-packages and caps\\/windows in a high-vacuum condition using this equipment. We also developed a micro-vacuum gauge to measure pressure in vacuum packages. The micro-vacuum gauge uses

Takeshi Matsumura; Takayuki Tokuda; Akinobu Tsutinaga; Masafumi Kimata; Hideyuki Abe; Naotaka Tokashiki

2010-01-01

244

Vacuum Technology:. Principles and Applications  

NASA Astrophysics Data System (ADS)

This work is devoted on principles and applications of vacuum technology. Classification and properties of vacuum are discussed. Various pumping mechanisms as well as three basic flow regimes namely viscous, intermediate and molecular are briefly presented. Gas-surface interaction concepts including physisorption and chemisorption states with their distinctive character as well as desorption phenomenon are considered. Two types of surface reaction mechanisms, Langmuir-Hinshelwood and Eley-Rideal are introduced. Applications of vacuum technology in the field of surface science, microfabrication, particle accelerators and analytical techniques are described. Finally, the use of vacuum in different industries with their corresponding applications is briefly reviewed.

Moshfegh, A. Z.

2004-06-01

245

Simulated Annealing Programming Using Eectiv e Subtrees  

Microsoft Academic Search

Simulated Annealing Programming (SAP), an automatic programming method, is an extension method of Simulated Annealing (SA) that allows SA to handle tree structures. In this method, the point to exchange is chosen randomly, and the subtree to insert is also generated randomly. In this paper, we propose the method that nds out eectiv e subtrees in search and that uses

Yuichiro UEDA; Mitsunori MIKI; Tomoyuki HIROYASU

246

An Evolutionary Annealing Approach to Graph Coloring  

Microsoft Academic Search

This paper presents a new heuristic algorithm for the graph coloring problem based on a combination of genetic algorithms and sim- ulated annealing. Our algorithm exploits a novel crossover operator for graph coloring. Moreover, we investigate various ways in which simulated annealing can be used to enhance the performance of an evolutionary al- gorithm. Experiments performed on various collections of

Dimitris A. Fotakis; Spiridon D. Likothanassis; Stamatis K. Stefanakos

2001-01-01

247

Thermal annealing and electrochemical purification of multi-walled carbon nanotubes produced by camphor/ferrocene mixtures.  

PubMed

Multi-walled carbon nanotubes (MWCNT) were obtained by pyrolysis of camphor/ferrocene mixtures, at different concentrations of ferrocene, on quartz, polished silicon and carbon felt substrates. A detailed study by electron microscopy, Raman spectroscopy, X-ray diffraction and thermogravimetric analysis was carried out to determine the purity degree of MWCNTs. Thermal annealing under vacuum and electrochemical purification were used for iron removal. The thermal annealing brings improvement on crystalline structure of MWCNTs, besides iron elimination from internal structure of the tubes, while the electrochemical treatments remove efficiently the iron from MWCNT surface. PMID:20352791

Antunes, E F; Almeida, E C; Rosa, C B F; de Medeiros, L I; Pardini, L C; Massi, M; Corat, E J

2010-02-01

248

Low-Temperature Annealing Effect of RF Inductor With FeNi-SiO2 Granular Film  

Microsoft Academic Search

A low-temperature annealing process in vacuum is proposed to enhance the inductance of RF inductors with FeNi-SiO2 magnetic granular films. Due to the great improvement of soft magnetic property in the 200degC and 350degC annealed film, the inductance is enhanced by 9.6% (200degC) and 8.3% (350degC), respectively, compared with the case of as-deposited film inductor. The peak value of quality

Hongfang Sun; Zewen Liu; Jiahao Zhao; Wang Li; Jing Zhu

2007-01-01

249

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

250

Resonant Rutherford backscattering spectrometry and channeling studies on the effect of annealing of La 0.67Ca 0.33MnO 3 epilayers grown on SrTiO 3( 0 0 1 ) substrates using a facing-target sputtering technique  

Microsoft Academic Search

La0.67Ca0.33MnO3 films are known to release oxygen upon vacuum annealing due to lattice expansion caused by change of valence state of Mn from Mn4+ to Mn3+. RBS measurements using O(?,?) resonance reaction at 3.043 MeV show that oxygen concentration decreases from 60% to 57% in 450 C-vacuum annealed samples. There is also oxygen loss from the SrTiO3 substrate upto a

B. Sundaravel; I. H. Wilson; E. Z. Luo; J. B. Xu; H. W. Yeung; H. Li; C. F. Yeung; J. R. Sun; H. K. Wong

2002-01-01

251

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

252

Atomic Steps on Thermally Annealed Oxide Substrates  

NASA Astrophysics Data System (ADS)

Atomically smooth perovskite oxide substrates are necessary for high quality thin-film growth. We have optimized the annealing conditions for the substrates, LaAlO3, SrTiO3 and NdGaO3, which are commonly used substrates for growing thin-film perovskite oxides. The optimal annealing temperatures were between 950 ^oC^ and 1050 ^oC and the annealing time for each sample was varied by approximately 20%. Atomic force microscopy was used to compare the surfaces of the annealed substrates with the unannealed ones. These images capture the terrace steps that occur due to the annealing process, and we have confirmed that the heights of the steps are approximately one unit cell (0.4 nm). Currently, we are investigating methods for determining the site termination of the substrates and their effects on thin-film growth.

Mazzaccari, Icon; Javed, Rafiya; Biswas, Amlan

2012-02-01

253

Cathodic phenomena in aluminum electrowinning  

NASA Astrophysics Data System (ADS)

Although aluminum is one of the world's highest production-volume primary metals, it is particularly costly to produce for a variety of factors, not the least of which are the expenses associated with electrolytic reduction. Based on the scale of global aluminum processing, even minor improvements in the electrowinning technology can result in significant savings of resources. Thus, from this perspective, the following reviews recent studies of cathodic phenomena in aluminum electrowinning.

Bouteillon, J.; Poignet, J. C.; Rameau, J. J.

1993-02-01

254

Thermodynamic constraints on fluctuation phenomena  

Microsoft Academic Search

The relationships between reversible Carnot cycles, the absence of perpetual\\u000amotion machines and the existence of a non-decreasing, globally unique entropy\\u000afunction forms the starting point of many textbook presentations of the\\u000afoundations of thermodynamics. However, the thermal fluctuation phenomena\\u000aassociated with statistical mechanics has been argued to restrict the domain of\\u000avalidity of this basis of the second law

O. J. E. Maroney

2009-01-01

255

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

256

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

257

Noise Induced Phenomena: a Sampler  

NASA Astrophysics Data System (ADS)

Fluctuations or noise have played a changing role in the history of science. Historically, we can identify three views of noise. In the first, up to the end of the 19th century, noise was considered a nuisance to be avoided or eliminated. This is still the implication of the definition of the word noise in any standard dictionary. A second stage dates from the beginning of the 20th century, when it became clear from the study of fluctuations via Onsager relations and fluctuation-dissipation relations that one can obtain useful information about a physical system from its fluctuations. The third stage started about three decades ago, and is marked by the realization that noise can actually play a central role in inducing new phenomena. Examples where noise leads to organized behavior include stochastic resonance, noise-induced phase transitions, noise-induced pattern formation, and noise-induced transport. In this minicourse we sample some such noise-induced phenomena. While many of these fluctuation-induced phenomena involve temporal fluctuations, spatial fluctuations (disorder) can also play a similar organizing role. We briefly illustrate this scenario as well.

Wio, Horacio S.; Lindenberg, Katja

2003-03-01

258

Entrapment Type Vacuum Pumps  

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. Entrapment type pumps operate primarily in the high to ultra-high vacuum ranges. The discussion in this MATEC module includes applications, theory of operation, operating range and preventative maintenance. The focus is on three major types of pumps: cryosorption, cryogenic and sputter-ion. The overall performance of these types of pumps depends on a variety of parameters. For example, it is important that learners understand the balance between pumping speed and capacity. Competency is demonstrated as the learners specify systems for defined process applications.

2012-12-20

259

Pseudoredundant vacuum energy  

NASA Astrophysics Data System (ADS)

We discuss models that can account for todays 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

2008-08-01

260

THERMOCOUPLE VACUUM GAUGE  

DOEpatents

A protector device is described for use in controlling the pressure within a cyclotron. In particular, an electrical circuit functions to actuate a vacuum pump when a predetermined low pressure is reached and disconnect the pump when the pressure increases abcve a certain value. The principal feature of the control circuit lies in the use of a voltage divider network at the input to a relay control tube comprising two parallel, adjustable resistances wherein one resistor is switched into the circuit when the relay connects the pump to a power source. With this arrangement the relay is energized at one input level received from a sensing element within the cyclotron chamber and is de-energized when a second input level, representing the higher pressure limit, is reached.

Price, G.W.

1954-08-01

261

Effect of annealing atmosphere on the contact resistivity, superconductivity, and phase transformation in the Al/BiSrCaCuO system  

SciTech Connect

This paper reports on the contact resistivity, superconductivity, and phase transformation in the Al/BiSrCaCuO(BSCCO) system annealed in air, argon, and vacuum, respectively. The BSCCO films were deposited by dc sputtering on MgO substrates. For the Al/BSCCO films, capped with gold and annealed at 750{degrees} C in air, the contact resistivity of 7 {times} 10{sup {minus}7} {Omega}-cm{sup 2} at 77 K can be obtained, whereas for the Al/BSCCO films annealed at above 500{degrees} C either in argon or in a vacuum of 6 {times} 10{sup {minus}6} Torr, the contact resistivities show semiconducting behavior due to degraded superconductivity of the BSCCO film. During annealing in argon or a vacuum of 6 {times} 10{sup {minus}6} Torr the melting temperatures of the 2212 phase are about 750 and 675{degrees} C, respectively. These are considerably lower than that in air, 875-895{degrees} C. The 2201 phase is the most stable phase in comparison with the 2212 and Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} phases during annealing in the oxygen-free atmosphere. The reversible change of the T{sub c} of the BSCCO film has an intimate relationship with the decomposition and recrystallization of the 2212 phase, depending on the annealing atmosphere. Two of the decomposition products of the 2212 phase for the BSCCO film annealed in the oxygen-free atmosphere are identified to be {delta}-Bi{sub 2}O{sub 3} and Cu{sub 2}O. In this study, the phase transformation and reversible change of the T{sub c} for the BSCCO film annealed in various atmospheres can be explained in terms of the desorption and absorption of oxygen in the film.

Lin, W.T.; Kao, H.P. (Dept. of Materials Engineering, National Cheng Kung Univ., Tainan (TW)); Fang, Y.K. (Inst. of Electrical and Computer Engineering, National Cheng Kung Univ., Tainan (TW)); Pan, F.M. (Materials Research Lab., ITRI, Hsinchu (TW))

1991-12-01

262

CC Cryostat Vacuum Pumping Efficiency  

Microsoft Academic Search

This report calculates the effect of the conductances of the pumping lines on the pumping speeds of the vacuum pumps being used to pump the inner vessel, and annular space, vacuum tight during the CC Cryostat testing. Effective pumping speeds were calculated for various values of pressure via the above stated formulas (see calculations). Conductances of valves, elbows, and tees

J. B. Fitzpatrick

1987-01-01

263

Chemical pumping in vacuum technology  

Microsoft Academic Search

Chemical pumping in vacuum technology has gained an ever increasing importance during the last two decades. It is based on the capability of metals, such as Zr, Ti, Ba and others, in pure or (more usually) alloy forms, to chemisorb the active residual gases present in vacuum devices or systems. These metals, used in powder form or in many different

B Ferrario

1996-01-01

264

Vacuum Technology:. Principles and Applications  

Microsoft Academic Search

This work is devoted on principles and applications of vacuum technology. Classification and properties of vacuum are discussed. Various pumping mechanisms as well as three basic flow regimes namely viscous, intermediate and molecular are briefly presented. Gas-surface interaction concepts including physisorption and chemisorption states with their distinctive character as well as desorption phenomenon are considered. Two types of surface reaction

A. Z. Moshfegh

2004-01-01

265

Ultrahigh Vacuum Twist Compression Apparatus  

Microsoft Academic Search

A new apparatus is described which is used for bonding of metals in ultrahigh vacuum by the twist compression technique. It is shown that adhesion between hard metal specimens can be readily measured in ultrahigh vacuum after some initial mechanical abrasion of the surfaces, while adhesion tests in air at atmospheric pressure do not yield measurable adhesion coefficients. Experimental results

J. M. Bradford; K. B. Wear; M. E. Sikorski

1970-01-01

266

Vacuum Requirements for LAMPF II.  

National Technical Information Service (NTIS)

The LAMPF II accelerator will require sufficient vacuum to prevent beam loss or beam blowup within the time the beam is in the accelerator. Because this time is quite short (tau < 0.03 s), the vacuum requirements should be somewhat less strict than for th...

D. Neuffer

1984-01-01

267

Edge conduction in vacuum glazing.  

National Technical Information Service (NTIS)

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. Edge conduction is problematic because it affects stresses in the edge region, l...

T. M. Simko R. E. Collins F. A. Beck D. Arasteh

1995-01-01

268

Vacuum Dewatering During Paper Manufacturing  

Microsoft Academic Search

Water removal during paper making is one of the most energy-intensive and capital-intensive processes. Vacuum dewatering is one of the intermediate stages of water removal on the paper machine where the compressible, wet mat is dewatered using applications of higher vacuum. A summary of the various stages of dewatering on the paper machine wire and the potential mechanisms of dewatering

S. Ramaswamy

2003-01-01

269

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

270

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

271

Properties of ZnO thin films deposited by chemical bath deposition and post annealed  

NASA Astrophysics Data System (ADS)

ZnO thin films deposited by chemical bath deposition (CBD) have been studied using x-ray diffraction, scanning electron microscopy, electron microprobe analysis and electrical measurements. The optimum CBD conditions for achieving structured, but adherent, ZnO films are as follows. Zinc acetate (0.0188 mol l-1) and ethylenediamine (0.03 mol l-1) are mixed. The pH of the bath is raised by addition of a base (0.5 mol l-1, NaOH). The solution is maintained at a temperature between 60 C and 65 C, while the bath is continuously stirred. We proceeded to anneal in room air for 30 min at 300 C and under vacuum for 2 h at 300 C. All the films obtained are nearly stoichiometric ZnO films crystallized in the usual hexagonal structure. As expected the films are rough and porous. The main difference between the two ZnO film families is their conductivity. The conductivity of the films annealed under vacuum is five orders of magnitude higher than that of those annealed in room air.

Ouerfelli, J.; Regragui, M.; Morsli, M.; Djeteli, G.; Jondo, K.; Amory, C.; Tchangbedji, G.; Napo, K.; Bernde, J. C.

2006-05-01

272

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

273

Cosmology with decaying vacuum energy  

SciTech Connect

Motivated by recent attempts to solve the cosmological constant problem, we examine the observational consequences of a vacuum energy density which decays in time. For all times later than t approx. 1 sec, the ratio of the vacuum to the total energy density of the universe must be small. Although the vacuum cannot provide the ''missing mass'' required to close the universe today, its presence earlier in the history of the universe could have important consequences. We discuss restrictions on the vacuum energy arising from primordial nucleosynthesis, the microwave and gamma ray background spectra, and galaxy formation. A small vacuum component at the era of nucleosynthesis, 0.01 < rho/sub vac//rho/sup rad/ < 0.1, increase the number of allowed neutino species to N/sup nu/ > 5, but in some cases would severely distort the microwave spectrum. 9 refs., 3 figs.

Freese, K.; Adams, F.; Frieman, J.; Mottola, E.

1987-09-01

274

Evaporation from a Liquid Surface under a High and a Medium Vacuum.  

National Technical Information Service (NTIS)

Observations on evaporation from liquid surface under a high and a medium vacuum revealed the existence of two new surface phenomena, icefield-torpid surface and concave-. Measurements of the effect of vapor pressure and of the inert gas on the rved to cl...

K. Toshiki U. Hajime Y. Osamu

1972-01-01

275

Motion of high-current vacuum arcs on spiral-type contacts  

Microsoft Academic Search

Motion of vacuum arcs on spiral-type contacts is not only controlled by self-induced magnetic fields, but also by heating phenomena. An expression is derived which permits the calculation of the speed of the arc from a computation of the time needed to heat the surface up to boiling temperature. The heat flux density of the constricted arc at the anode

EDGAR DULLNI

1989-01-01

276

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

277

The Time-Resolved Characterization of Erosion Products from High-Current, Copper Vacuum Arcs  

Microsoft Academic Search

A vacuum arc at high enough current can produce gross melting on electrode surfaces as a consequence of anode spot formation and other high-current electrode phenomena. Erosion from the electrodes under this condition is much more rapid than at low-current (where material loss occurs principally from the cathode) and is a process that is presently poorly understood. The present work

G. A. Farrall; F. G. Hudda; J. G. Toney

1983-01-01

278

A computer simulation of transformer magnetising current interruption by a vacuum circuit breaker  

Microsoft Academic Search

A computer program has been elaborated to calculate the switching overvoltages during transformer interruption of a magnetising current by a vacuum circuit breaker (VCB). This program uses the Monte Carlo simulation technique and takes into account three-phase switching phenomena in an isolated neutral electric circuit. The distinguishing feature of this program is the application of a current chopping model, based

Alexey M. Chaly; Alevtina T. Chalaya

1996-01-01

279

Modeling some two-dimensional relativistic phenomena using an educational interactive graphics software  

NASA Astrophysics Data System (ADS)

This paper describes several relativistic phenomena in two spatial dimensions that can be modeled using the collision program of Spacetime Software. These include the familiar aberration, the Doppler effect, the headlight effect, and the invariance of the speed of light in vacuum, in addition to the rather unfamiliar effects like the dragging of light in a moving medium, reflection at moving mirrors, Wigner rotation of noncommuting boosts, and relativistic rotation of shrinking and expanding rods. All these phenomena are exhibited by tracings of composite computer printouts of the collision movie. It is concluded that an interactive educational graphics software with pleasing visuals can have considerable investigative power packed within it.

Sastry, G. P.; Ravuri, Tushar R.

1990-11-01

280

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

281

Further Investigations of Oblique Hypervelocity Impact Phenomena.  

National Technical Information Service (NTIS)

The results of a continuing investigation of the phenomena associated with the oblique hypervelocity impact of spherical projectiles onto multi-sheet aluminum structures are described. A series of equations that quantitatively describes these phenomena is...

W. P. Schonberg

1988-01-01

282

Astronomical Phenomena for the Year 1991.  

National Technical Information Service (NTIS)

Astronomical phenomena for the year 1991 are presented in tabular form. Data is given on seasons, Moon phases, eclipses, occultations, perigee and apogee of the Moon, geocentric and heliocentric planetary phenomena, times of meridian passages of planets, ...

1990-01-01

283

Rotary bayonets for cryogenic and vacuum service.  

National Technical Information Service (NTIS)

Rotary bayonets were designed, tested, and installed for liquid nitrogen, liquid argon, and vacuum service. This paper will present the design, testing, and service record for two sizes of vacuum jacketed cryogenic rotary bayonets and two sizes of vacuum ...

R. A. Rucinski K. D. Dixon R. Krasa K. J. Krempetz G. T. Mulholland

1993-01-01

284

14 CFR 25.1433 - Vacuum systems.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 false Vacuum systems. 25.1433 Section...AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES...Equipment § 25.1433 Vacuum systems. There must be...discharge lines from the vacuum air pump when the...

2013-01-01

285

14 CFR 29.1433 - Vacuum systems.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 false Vacuum systems. 29.1433 Section...AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT...Equipment § 29.1433 Vacuum systems. (a) There...unsafe. (b) Each vacuum air system line and...

2013-01-01

286

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

287

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

PubMed

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 changes in the surface structure and topology. Recrystallization and surface reconstruction is less pronounced on the 316LN stainless steel. AP depth profiling analyses result in noticeable nickel enrichment on the surface of grade 304L samples. Since hydrogen recombination is almost controlled by surface structure and composition, a strong influence on the outgassing behaviour by the particular surface microstructure can be deduced. PMID:19167824

Stupnik, A; Frank, P; Leisch, M

2008-12-07

288

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 architecturecrystalline 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

289

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

290

Emergent phenomena at oxide interfaces.  

PubMed

Recent technical advances in the atomic-scale synthesis of oxide heterostructures have provided a fertile new ground for creating novel states at their interfaces. Different symmetry constraints can be used to design structures exhibiting phenomena not found in the bulk constituents. A characteristic feature is the reconstruction of the charge, spin and orbital states at interfaces on the nanometre scale. Examples such as interface superconductivity, magneto-electric coupling, and the quantum Hall effect in oxide heterostructures are representative of the scientific and technological opportunities in this rapidly emerging field. PMID:22270825

Hwang, H Y; Iwasa, Y; Kawasaki, M; Keimer, B; Nagaosa, N; Tokura, Y

2012-01-24

291

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

292

Multifractal phenomena in physics and chemistry  

Microsoft Academic Search

A brief introduction to multifractal phenomena, different regions of an object that have different fractal properties, is given. The application of the concept of multifractal phenomena to complex surfaces and interfaces and to fluid flow in porous media is discussed. Analogies of multifractals with thermodynamics and multifractal scaling are pointed out. The association of multifractal phenomena with systems where the

H. Eugene Stanley; Paul Meakin

1988-01-01

293

Characterization of e-beam evaporated hafnium oxide thin films on post thermal annealing  

NASA Astrophysics Data System (ADS)

HfO2 thin films (80 nm thick) were fabricated using electron beam evaporation technique at various substrate temperatures ranging from 25 to 120 C. These films were then thermally annealed at 500 C for one and half hour in vacuum. After thermal annealing, films were characterized through XRD, AFM and Spectrophotometry. In this regard, it was observed that the as-deposited HfO2 films were mostly amorphous in nature and transformed to polycrystalline with monoclinic structure after annealing at 500 C. Moreover, films fabricated at different substrate temperatures revealed different morphologies and crystallite orientations on thermal annealing. Such different morphologies and crystallite orientations appear to be responsible for any variations in the surface roughness and the optical properties e.g. optical band gap energy (3.43.65 eV), refractive index (1.252.55), extinction coefficient (0.250.46) etc. These optical properties demonstrate oscillatory behavior with different substrate temperatures due to crystallite growth along different preferred orientations. On the basis of above mentioned facts, it can be concluded that the post thermal annealing demonstrates better tendency to change the structural and optical properties of HfO2 thin films. In addition, annealed HfO2 films showed better reflectivity (510%) in the NIR region which can further be improved by inserting a metallic layer into the oxidemetaloxide (OMO) structure. Hence, such OMO structures can be useful for heat mirror applications.

Ramzan, M.; Wasiq, M. F.; Rana, A. M.; Ali, S.; Nadeem, M. Y.

2013-10-01

294

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

295

The electrical resistance of vacuum  

NASA Astrophysics Data System (ADS)

This paper deals with the physics of electrical conduction in vacuum between two parallel conducting planes (planar vacuum diode). After reviewing known features of conduction in the high-voltage range, we turn to the low-voltage range. An ohmic current-voltage characteristic is calculated in the case of identical cathodic and anodic electrodes, whence an electrical resistance of the vacuum gap can be defined. The inverse resistance involves the elemental conductance 2e 2/h and the number of conductance channels between the two electrodes. The channels are thermally populated from the electrodes and the population is analytically calculable from the Poisson equation of electrostatics and the Boltzmann law of thermal equilibrium. The observed resistance of a real vacuum diode (Mullard's EB 91) is accounted for without adjusting parameters. The paper also examines the link-up between Joule's law, involving dissipation, and Ohm's law, with vacuum being contrasted with a material conducting medium; the origin of dissipation in vacuum is understood. Quantum and statistical physics are kept at the undergraduate level. Finally, the results obtained for the vacuum diode shed light upon the quantized conductance of nanoscale semiconductor wires, a topic usually handled only in graduate courses.

Bringuier, E.

2013-07-01

296

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

297

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

298

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

299

Anodic vacuum arc developed nanocrystalline CuNi and FeNi thin film thermocouples  

Microsoft Academic Search

This paper deals with the development of nanocrystalline CuNi and FeNi thin film thermocouples (TFTCs) by using ion-assisted anodic vacuum arc deposition technique. The crystallographic structure and surface morphology of individual layer films have been studied by x-ray diffraction and scanning electron microscopy, respectively. The resistivity, temperature coefficient of resistance, and thermoelectric power of as deposited and annealed films have

S. K. Mukherjee; M. K. Sinha; B. Pathak; S. K. Rout; P. K. Barhai

2009-01-01

300

Anodic vacuum arc developed nanocrystalline Cu-Ni and Fe-Ni thin film thermocouples  

Microsoft Academic Search

This paper deals with the development of nanocrystalline Cu-Ni and Fe-Ni thin film thermocouples (TFTCs) by using ion-assisted anodic vacuum arc deposition technique. The crystallographic structure and surface morphology of individual layer films have been studied by x-ray diffraction and scanning electron microscopy, respectively. The resistivity, temperature coefficient of resistance, and thermoelectric power of as deposited and annealed films have

S. K. Mukherjee; M. K. Sinha; B. Pathak; S. K. Rout; P. K. Barhai

2009-01-01

301

Recent experiments on vacuum breakdown of oxygen-free copper electrodes  

Microsoft Academic Search

The effects of the gas content, in situ sputter cleaning, annealing and a mirror finish of OFC (oxygen-free copper) electrodes on the electrical breakdown in a vacuum were investigated. The grade of the OFC meets the ASTM-F-68 class 1 standard. ECB (electrochemical buffing) or diamond turning was employed for obtaining a mirror finish. It was found that every one of

S. Kobayashi

1997-01-01

302

An observation of charge trapping phenomena in GaN\\/AlGaN\\/Gd2O3\\/Ni-Au structure  

Microsoft Academic Search

Charge trapping, especially electron trapping phenomena in GaN\\/AlGaN\\/Gd2O3\\/Ni-Au metal-oxide-semiconductor structure have been investigated. Owing to crystallization of Gd2O3 film after annealing at 900 C in ambient air for 30 s, a significant memory window of 1.6 V is observed under 5 V@100 ms programming pulse compared with that of as-deposited sample. The fabricated structure exhibits no erase phenomena under large

Liann Be Chang; Atanu Das; Ray Ming Lin; Siddheswar Maikap; Ming Jer Jeng; Shu Tsun Chou

2011-01-01

303

An observation of charge trapping phenomena in GaN\\/AlGaN\\/Gd2O3\\/NiAu structure  

Microsoft Academic Search

Charge trapping, especially electron trapping phenomena in GaN\\/AlGaN\\/Gd2O3\\/NiAu metal-oxide-semiconductor structure have been investigated. Owing to crystallization of Gd2O3 film after annealing at 900 C in ambient air for 30 s, a significant memory window of 1.6 V is observed under 5 V@100 ms programming pulse compared with that of as-deposited sample. The fabricated structure exhibits no erase phenomena under large

Liann Be Chang; Atanu Das; Ray Ming Lin; Siddheswar Maikap; Ming Jer Jeng; Shu Tsun Chou

2011-01-01

304

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

305

Thermoelectric Phenomena, Materials, and Applications  

NASA Astrophysics Data System (ADS)

Over the past 10-15 years, there have been significant advances in the scientific understanding as well as in the performance of thermoelectric (TE) materials. TE materials can be incorporated into power generation devices that are designed to convert waste heat into useful electrical energy. These TE materials can also be used in solid-state refrigeration devices for cooling applications. The conversion of waste heat into electrical energy will certainly play a role in our current challenge for alternative energy technologies to reduce our dependence on fossil fuels and to reduce greenhouse gas emissions. This article provides an overview of the various TE phenomena and discusses some of the primary TE materials that are currently being investigated. Several of the key parameters and terminology are defined and discussed along with an overview of some of the current and emerging technologies. The phonon glass-electron crystal approach to new TE materials for developing new materials is presented along with the role of solid-state crystal chemistry and the criteria for higher-performance TE materials. This article discusses TE phenomena, the selection criteria for higher-performance materials, and a few key materials.

Tritt, Terry M.

2011-08-01

306

Effects of annealing atmosphere and temperature on properties of ZnO thin films on porous silicon grown by plasma-assisted molecular beam epitaxy  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) thin films were grown on porous silicon (PS) by plasma-assisted molecular beam epitaxy (PA-MBE). The thin films were annealed in various atmospheres such as argon, nitrogen, and vacuum, and their structural and optical properties were investigated by scanning electron microscopy, X-ray diffraction, and photoluminescence. The ZnO thin films grown on PS showed a mountain-range-like surface morphology, whereas those grown on Si showed a typical 3D island surface structure. The thin films grown on PS exhibited only one diffraction peak at 34, whereas those grown on Si showed shoulders of the ZnO (002) diffraction peaks at around 33; this implies an excellent c-axis preferred orientation and a better crystal quality when PS was used. Large crystals were partially formed at an annealing temperature of 700C. The films annealed in a vacuum showed nanorod-like ZnO crystals, whereas those annealed in nitrogen and oxygen showed irregularly shaped crystals. It was confirmed that the structural and optical properties of the thin films were enhanced by the annealing process. In particular, relatively large changes in the full width at half maximum of the ZnO (002) diffraction peaks and UV emission peaks, indicating enhanced structural and optical properties, respectively, were observed when the thin films were annealed in argon.

Kim, Min Su; Kim, Tae Hoon; Kim, Do Yoeb; Lee, Dong-Yul; Kim, Sung-O.; Leem, Jae-Young

2012-04-01

307

Annealing effects on the structural and optical properties of AgIn 5S 8 thin films  

Microsoft Academic Search

Due to its importance as a perspective material for application in optoelectronic semiconductor devices, the thermal annealing effects on the structural and optical properties of the as-grown vacuum evaporated AgIn5S8 thin films have been investigated. The X-ray data analysis have shown that these films are polycrystalline in nature and exhibit better crystallization with increasing crystallite size and slightly, decreasing unit

A. F. Qasrawi

2008-01-01

308

Synthesis of large area, homogeneous, single layer graphene films by annealing amorphous carbon on Co and Ni  

Microsoft Academic Search

The synthesis of large area, homogenous, single layer graphene on cobalt (Co) and nickel (Ni) is reported. The process involves\\u000a vacuum annealing of sputtered amorphous carbon (a-C) deposited on Co\\/sapphire or Ni\\/sapphire substrates. The improved crystallinity\\u000a of the metal film, assisted by the sapphire substrate, proves to be the key to the quality of as-grown graphene film. The\\u000a crystallinity of

Carlo M. Orofeo; Hiroki Ago; Baoshan Hu; Masaharu Tsuji

2011-01-01

309

Effect of annealing temperature on microstructure, hardness and adhesion properties of TiSi x N y superhard coatings  

Microsoft Academic Search

A series of TiSixNy superhard coatings with different Si contents were prepared on M42 steel substrates using two Ti and two Si targets by reactive magnetron sputtering at 500C. These samples were subsequently vacuum-annealed at 500, 600, 700, 800 and 900C, respectively. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), microindenter, Rockwell hardness tester and scratch tester were applied to investigate

Y. H. Lu; J. P. Wang; S. L. Tao; Z. F. Zhou

2011-01-01

310

Desorption of InSb(001) native oxide and surface smoothing induced by low temperature annealing under molecular hydrogen flow  

Microsoft Academic Search

The preparation of InSb (001) oxygen-free surfaces by thermal annealing at relatively low temperatures under molecular hydrogen flow is reported. This process is compared with thermal oxide desorption (TOD) at 400 C under ultrahigh vacuum conditions. Molecular hydrogen cleaning (MHC) at substrate temperature of 250 C and at hydrogen pressure of 510-6 Torr resulted in complete desorption of the native

R. Tessler; C. Saguy; O. Klin; S. Greenberg; E. Weiss; R. Akhvlediani; R. Edrei; A. Hoffman

2007-01-01

311

Effect of the surface condition of titanium alloy components on their working capacity after annealing in different atmospheres  

Microsoft Academic Search

1.During annealing in vacuum furnaces with a specific air leakage rate of Qsp>13.3 mPa\\/sec, and also in furnaces with an argon atmosphere (with insufficient furnace sealing or with the use of unpurified argon), and with an air atmosphere, there is impregnation of surface layers with oxygen and carbon which leads to an increase in their microhardness, and as a result

E. A. Borisova; I. I. Shashenkova; M. V. Zakharova

1986-01-01

312

Numerical study on sublimationcondensation phenomena during microwave freeze drying  

Microsoft Academic Search

A sublimationcondensation model is developed for freeze drying of unsaturated porous media. The governing equations describing the drying process are solved numerically with variable time step finite-difference method. The sublimationcondensation phenomena during microwave freeze drying are studied numerically for different operating conditions including electric field strength, sample thickness, and vacuum pressure. The results show that the sublimationcondensation effects depend on

Zhao Hui Wang; Ming Heng Shi

1998-01-01

313

Cross-equipment study on charging phenomena of solid insulators in high voltage equipment  

Microsoft Academic Search

This paper reports on a new cross-equipment study on the charging phenomena of solid insulators, evaluating the influence of charging on high-voltage equipment such as gas insulated switchgear (GIS), oil-immersed transformers, gas-insulated transformers and high-voltage vacuum-insulated equipment. New parameters of normalized charge density and surface resistance are introduced to consistently explain all the characteristics of the surface charge density on

H. Hama; T. Hikosaka; S. Okabe; H. Okubo

2007-01-01

314

Fabrication by Coaxial-Type Vacuum Arc Evaporation Method and Characterization of Bismuth Telluride Thin Films  

NASA Astrophysics Data System (ADS)

We prepared both n- and p-type bismuth telluride thin films by using a coaxial-type vacuum arc evaporation method. The atomic compositions of the as-grown thin films and several annealed thin films were comparable to that of bulk bismuth telluride. Their thermoelectric properties were measured and found to be comparable to those of bulk materials. The Seebeck coefficient and electrical conductivity of the as-grown thin films were improved by the annealing process. The measured figures of merit ( ZT) of the films were 0.86 for the n-type and 0.41 for the p-type at 300 K for annealing temperatures of 573 K and 523 K, respectively.

Uchino, M.; Kato, K.; Hagino, H.; Miyazaki, K.

2013-07-01

315

Optical Characterization of CuInSe2 Thin Films Prepared by Vacuum Thermal Evaporation Method  

NASA Astrophysics Data System (ADS)

In the present research work, we have deposited Copper Indium diselenide (CuInSe2) thin films on to well cleaned glass substrates in a vacuum 10-5 Torr. The as-deposited films were annealed in air at different temperatures. Optical absorption spectra of CuInSe2 thin films were investigated using optical absorption spectroscopy. Direct energy band gap values for CuInSe2 thin films were derived from the variation of (?h?)2 with energy (h?). The structural and morphological properties of thin films (as-deposited & annealed) were characterized by X-ray diffraction (XRD) analysis and optical microscopy. After annealing, the XRD pattern reveals that the films are polycrystalline in nature. The optical micrograph shows that the as-deposited films have a uniform surface morphology with homogeneity distribution of crystallites.

Sharma, Mahesh Chand; Tirpathi, Balram; Vijay, Y. K.

2011-10-01

316

Postshock Annealing of the Baszkwka Meteorite  

NASA Astrophysics Data System (ADS)

Chromite-plagioclase assemblages, native copper flanks and macroporosity are observed in the Baszkwka meteorite. Silicates however do not show crystal defects. Healed cracks testify on the annealing of their structure after strong shock event.

Krzesi?ska, A.

2012-09-01

317

Self-Annealing of Sendai Virus RNA  

PubMed Central

Both complementary strands are found in 50S Sendai virion RNA. 50S Sendai virion RNA has been shown to consist of unequal amounts of a single population of plus and minus strands by annealing studies. Images

Kolakofsky, Daniel; de la Tour, Edward Boy; Bruschi, Andree

1974-01-01

318

Annealing behavior of high permeability amorphous alloys  

SciTech Connect

Effects of low temperature annealing on the magnetic properties of the amorphous alloy Co/sub 71/ /sub 4/Fe/sub 4/ /sub 6/Si/sub 9/ /sub 6/B/sub 14/ /sub 4/ were investigated. Annealing this alloy below 400/sup 0/C results in magnetic hardening; annealing above 400/sup 0/C but below the crystallization temperature results in magnetic softening. Above the crystallization temperature the alloy hardens drastically and irreversibly. Conventional and high resolution transmission electron microscopy were used to show that the magnetic property changes at low temperatures occur while the alloy is truly amorphous. By imaging the magnetic microstructures, Lorentz electron microscopy has been able to detect the presence of microscopic inhomogeneities in this alloy. The low temperature annealing behavior of this alloy has been explained in terms of atomic pair ordering in the presence of the internal molecular field. Lorentz electron microscopy has been used to confirm this explanation.

Rabenberg, L.

1980-06-01

319

Enthalpy relaxation and annealing effect in polystyrene.  

PubMed

The effects of thermal history on the enthalpy relaxation in polystyrene are studied by differential scanning calorimetry. The temperature dependence of the specific heat in the liquid and the glassy states, that of relaxation time, and the exponent of the Kohlrausch-Williams-Watts function are determined by measurements of the thermal response against sinusoidal temperature variation. A phenomenological model equation previously proposed to interpret the memory effect in the frozen state is applied to the enthalpy relaxation and the evolution of entropy under a given thermal history is calculated. The annealing below the glass transition temperature produces two effects on enthalpy relaxation: the decay of excess entropy with annealing time in the early stage of annealing and the increase in relaxation time due to physical aging in the later stage. The crossover of these effects is reflected in the variation of temperature of the maximum specific heat observed in the heating process after annealing and cooling. PMID:23944484

Sakatsuji, Waki; Konishi, Takashi; Miyamoto, Yoshihisa

2013-07-23

320

Maneuver Optimization through Simulated Annealing  

NASA Astrophysics Data System (ADS)

We developed an efficient method for satellite maneuver optimization. It is based on a Monte Carlo (MC) approach in combination with Simulated Annealing. The former component enables us to consider all imaginable trajectories possible given the current satellite position and its available thrust, while the latter approach ensures that we reliably find the best global optimization solution. Furthermore, this optimization setup is eminently scalable. It runs efficiently on the current multi-core generation of desktop computers, but is equally at home on massively parallel high performance computers (HPC). The baseline method for desktops uses a modified two-body propagator that includes the lunar gravitational force, and corrects for nodal and apsidal precession. For the HPC environment, on the other hand, we can include all the necessary components for a full force-model propagation: higher gravitational moments, atmospheric drag, solar radiation pressure, etc. A typical optimization scenario involves an initial orbit and a destination orbit / trajectory, a time period under consideration, and an available amount of thrust. After selecting a particular optimization (e.g., least amount of fuel, shortest maneuver), the program will determine when and in what direction to burn by what amount. Since we are considering all possible trajectories, we are not constrained to any particular transfer method (e.g., Hohmann transfers). Indeed, in some cases gravitational slingshots around the Earth turn out to be the best result. The paper will describe our approach in detail, its complement of optimizations for single- and multi-burn sequences, and some in-depth examples. In particular, we highlight an example where it is used to analyze a sequence of maneuvers after the fact, as well as showcase its utility as a planning and analysis tool for future maneuvers.

de Vries, W.

2011-09-01

321

Sputtered Cu/Co films for giant magnetoresistance: Effect of plasma gas and annealing treatment  

SciTech Connect

Sputtered Co/Cu films were deposited on silicon either directly, using an argon plasma, or through an intermediate step involving the deposition of CoN/Cu{sub 3}N by reactive sputtering in a nitrogen plasma. The nitride composite was pyrolyzed to release the nitrogen. The effect of preparation route and different annealing treatments on the resistivity of these films as a function of magnetic field and temperature was established. As in previous studies particle size is of primary importance in determining the giant magnetoresistance (GMR) characteristics of a film; thus optimizing the magnitude of the GMR effect requires close control of the duration and temperature of annealing treatments. The microstructure of these films was examined by means of atomic force microscopy. The intermediate nitride step produced a film in which the GMR effect was degraded apparently through the inclusion of voids that are not eliminated in the pyrolysis stage. {copyright} {ital 1997 American Vacuum Society.}

Maya, L.; Paranthaman, M. [Chemical and Analytical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6119 (United States); List, F.A. [Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Warmack, R.J. [Health Sciences Research Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

1997-09-01

322

Investigation of Impact Behavior of Cold-Sprayed Large Annealed Copper Particles and Characterization of Coatings  

NASA Astrophysics Data System (ADS)

In this research, the large gas-atomized copper powder was selected as the feedstock. Some powder was annealed in a vacuum circumstance to avoid the effect of grain boundaries on the high velocity impact behavior of particles during cold spraying. The annealed Cu powder was deposited by cold spraying with respect to the single impacts and coating deposition under certain gas condition. In addition, the rebounded copper particles were collected for morphology analysis compared to the adhered particles. The results show that the average size of the rebounded particles is apparently increased compared with the starting powder because of the rebounding of larger particles and intensive plastic deformation of the rebounded particles. For the deposited particles, obvious plastic deformation causes a higher hardness to the coating. It is found that the rebounded particles have also experienced large deformation and shear instability at the impact interfaces.

Li, Wenya; Guo, Xueping; Yu, Min; Liao, Hanlin; Coddet, Christian

2011-01-01

323

Investigation of Impact Behavior of Cold-Sprayed Large Annealed Copper Particles and Characterization of Coatings  

NASA Astrophysics Data System (ADS)

In this research, the large gas-atomized copper powder was selected as the feedstock. Some powder was annealed in a vacuum circumstance to avoid the effect of grain boundaries on the high velocity impact behavior of particles during cold spraying. The annealed Cu powder was deposited by cold spraying with respect to the single impacts and coating deposition under certain gas condition. In addition, the rebounded copper particles were collected for morphology analysis compared to the adhered particles. The results show that the average size of the rebounded particles is apparently increased compared with the starting powder because of the rebounding of larger particles and intensive plastic deformation of the rebounded particles. For the deposited particles, obvious plastic deformation causes a higher hardness to the coating. It is found that the rebounded particles have also experienced large deformation and shear instability at the impact interfaces.

Li, Wenya; Guo, Xueping; Yu, Min; Liao, Hanlin; Coddet, Christian

2010-07-01

324

Field emission from products of nanodiamond annealing  

Microsoft Academic Search

Field emission characteristics were measured for the samples produced by controlled annealing of nanodiamonds (ND) leading to the formation of sp2\\/sp3 composites containing diamond core encapsulated in curved graphitic scales, onion-like carbon, and hollow graphite polyhedrons. The sequential raise in the ND annealing temperature was found to result in no monotonic change of emission threshold value of the products. The

A. V. Okotrub; L. G. Bulusheva; A. V. Gusel'nikov; V. L. Kuznetsov; Yu. V. Butenko

2004-01-01

325

The Theory and Practice of Simulated Annealing  

Microsoft Academic Search

Simulated annealing is a popular local search meta-heuristic used to address discrete and, to a lesser extent, continuous optimization problems. The key feature of simulated annealing is that it provides a means to escape local optima by allowing hill-climbing moves (i.e., moves which worsen the objective function value) in hopes of finding a global optimum. A brief history of simulated

Darrall Henderson; Sheldon H. Jacobson; Alan Johnson

326

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

327

Laser annealing of thin organic films  

NASA Astrophysics Data System (ADS)

Microstructure of defects in organic solar cells containing PEDOT:PSS:Sorbitol layer has been studied and conditions for successful pulsed laser annealing of them have been determined. Investigation with oblique illumination showed that radial symmetry of fine structure is an intrinsic property of either separated discotic defects or block structure. Our study shows that pulsed laser annealing of organic thin films in inert atmosphere has promising future.

Agashkov, A. V.; Ivlev, G. D.; Filippov, V. V.; Kashko, I. A.; Shulitski, B. G.

2010-09-01

328

Recovery of surface conductivity of H-terminated diamond after thermal annealing in vacuum  

Microsoft Academic Search

A unique feature of diamond among other semiconductors is the formation of a high conductive p-type layer which is usually obtained after hydrogen-termination of the surface. It is generally accepted that the appearance of surface conductivity (SC) requires the presence of atmospheric adsorbates. We present a combination of conductivity and spectroscopic measurements dealing with the loss and the formation of

M. Riedel; J. Ristein; L. Ley

2004-01-01

329

Pulsed and continuous wave solid phase laser annealing of electrodeposited CuInSe2 thin films  

NASA Astrophysics Data System (ADS)

Cu(In,Ga)Se2 (CIGS) thin film photovoltaic absorber layers are primarily synthesized by vacuum based techniques at industrial scale. In this work, we investigate non-vacuum film synthesis by electrochemical deposition coupled with pulsed laser annealing (PLA) and or continuous wave laser annealing (CWLA) using 1064 nm laser. PLA results indicate that at high fluence (>=100 mJ/cm2) CuInSe2 films melt and dewet on both Mo and Cu substrates. In the submelt PLA regime (<=70 mJ/cm2) no change in XRD results is recorded. However CWLA at 50 W/cm2 for up to 45 s does not result in melting or dewetting of the film. XRD and Raman data indicate more than 80% reduction in full width at half maximum (FWHM) in their respective main peaks for annealing time of 15 s or more. No other secondary phases are observed in XRD or Raman spectrum. These results might help us in setting up the foundation for processing CIGS through an entirely non-vacuum process.

Bhatia, Ashish; Meadows, Helen; Crossay, Alexandre; Dale, Phillip J.; Scarpulla, Michael A.

2012-10-01

330

Vacuum-Assisted Vaginal Delivery  

PubMed Central

Approximately 5% (1 in 20) of all deliveries in the United States are operative vaginal deliveries. The past 20 years have seen a progressive shift away from the use of forceps in favor of the vacuum extractor as the instrument of choice. This article reviews in detail the indications, contraindications, patient selection criteria, choice of instrument, and technique for vacuum-assisted vaginal delivery. The use of vacuum extraction at the time of cesarean delivery will also be discussed. With vacuum extraction becoming increasingly popular, it is important that obstetric care providers are aware of the maternal and neonatal risks associated with such deliveries and of the options available to effect a safe and expedient delivery.

Ali, Unzila A; Norwitz, Errol R

2009-01-01

331

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

332

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 nTorr, consists of 240 connected sections, the majority of which are fabricated from an aluninum alloy extrusion. The sections are equipped with distributed NeG pumping, photon absorbers with lumped pumping, beam position monitors, vacuum diagnostics and valving. The detaileds of the vacuum system design, selected results of the development program and general construction plans are presented.

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. (Argonne National Laboratory, Argonne, Illinois 60439 (United States))

1991-08-20

333

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

334

Vacuum microelectronic devices [and prolog  

Microsoft Academic Search

In this review\\/tutorial paper, we cover the history, physics, and current status of vacuum microelectronic devices. First we overview the performance requirements of vacuum microelectronic devices necessary for them to replace, or fill voids left by, solid state devices. Next we discuss the physical characteristics of micro-field-emission sources important to device applications. These characteristics include fundamental features, such as current-voltage

IVOR BRODIE; PAUL RICHARD SCHWOEBEL

1994-01-01

335

Vacuum frying of potato chips  

Microsoft Academic Search

Vacuum frying was tested as an alternative technique to develop low oil content potato chips. The effect of oil temperature (118, 132, 144 C) and vacuum pressure (16.661, 9.888, and 3.115 kPa) on the drying rate and oil absorption of potato chips and on the product quality attributes such as shrinkage, color, and texture was investigated. Furthermore, the characteristics of

Jagoba Garayo; Rosana Moreira

2002-01-01

336

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

337

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

338

Critical phenomena in magnetic nanowires.  

PubMed

In this paper we report the first experimental study of critical phenomena in case of magnetic nanowires of nickel near the ferromagnetic-paramagnetic transition from the electrical transport properties. Nickel nanowire arrays, prepared by potentiostatic electrodeposition of nickel inside pores of nanoporous anodic alumina template were well characterized by X-ray Diffraction, Transmission electron microscopy and Energy dispersive Spectroscopy. Precise electrical resistance measurement of the nanowire arrays of wire diameter 20 nm have been done in the temperature range between 300 K to 700 K. We see a drop in the Curie temperature as observed from the resistivity anomaly. We analyzed the resistance data near the critical region and extracted the critical exponent alpha directly from the resistance. We observed a decrease in the critical part of the resistivity including a decrease in the magnitude of the critical exponent alpha and severe modification in the correction to scaling. PMID:19928208

Kamalakar, M Venkata; Raychaudhuri, A K

2009-09-01

339

Relaxation phenomena in cryogenic electrolytes  

NASA Astrophysics Data System (ADS)

Proposed is a scenario for the development of observed relaxation phenomena in a cryogenic electrolyte with the structure of ``liquid hydrogen + injected ions.'' Ions of one sign are generated in the bulk of liquid hydrogen in the presence of external field E? by a stationary radioactive source of +/- ions at the bottom of a vessel. After accumulation near the free surface of the liquid with a finite density ns the ions can break its stability producing a pulse of ion current to the collector located above the liquid surface. The outlined process is periodically repeated. Its period contains information on the ion mobility and, which is most interesting, on dissociation (association) processes occurring in a system of charged particles placed in an external field. The cryogenic problem is a good model for dissociation in the presence of external field occurring in normal electrolytes without any external ion sources.

Shikin, V.; Chikina, I.; Nazin, S.

2013-06-01

340

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.

341

Emergent Phenomena at Oxide Interfaces  

SciTech Connect

Transition metal oxides (TMOs) are an ideal arena for the study of electronic correlations because the s-electrons of the transition metal ions are removed and transferred to oxygen ions, and hence the strongly correlated d-electrons determine their physical properties such as electrical transport, magnetism, optical response, thermal conductivity, and superconductivity. These electron correlations prohibit the double occupancy of metal sites and induce a local entanglement of charge, spin, and orbital degrees of freedom. This gives rise to a variety of phenomena, e.g., Mott insulators, various charge/spin/orbital orderings, metal-insulator transitions, multiferroics, and superconductivity. In recent years, there has been a burst of activity to manipulate these phenomena, as well as create new ones, using oxide heterostructures. Most fundamental to understanding the physical properties of TMOs is the concept of symmetry of the order parameter. As Landau recognized, the essence of phase transitions is the change of the symmetry. For example, ferromagnetic ordering breaks the rotational symmetry in spin space, i.e., the ordered phase has lower symmetry than the Hamiltonian of the system. There are three most important symmetries to be considered here. (i) Spatial inversion (I), defined as r {yields} -r. In the case of an insulator, breaking this symmetry can lead to spontaneous electric polarization, i.e. ferroelectricity, or pyroelectricity once the point group belongs to polar group symmetry. (ii) Time-reversal symmetry (T) defined as t {yields} -t. In quantum mechanics, the time-evolution of the wave-function {Psi} is given by the phase factor e{sup -iEt/{h_bar}} with E being the energy, and hence time-reversal basically corresponds to taking the complex conjugate of the wave-function. Also the spin, which is induced by the 'spinning' of the particle, is reversed by time-reversal. Broken T-symmetry is most naturally associated with magnetism, since the spin operator changes sign with T-operation. (iii) Gauge symmetry (G), which is associated with a change in the phase of the wave-function as {Psi} {yields} e{sup i{theta}}{Psi}. Gauge symmetry is connected to the law of charge conservation, and broken G-symmetry corresponds to superconductivity/superfluidity. To summarize, the interplay among these electronic degrees of freedom produces various forms of symmetry breaking patterns of I, T, and G, leading to novel emergent phenomena, which can appear only by the collective behavior of electrons and cannot be expected from individual electrons. Figure 1 shows this schematically by means of several representative phenomena. From this viewpoint, the interfaces of TMOs offer a unique and important laboratory because I is already broken by the structure itself, and the detailed form of broken I-symmetry can often be designed. Also, two-dimensionality usually enhances the effects of electron correlations by reducing their kinetic energy. These two features of oxide interfaces produce many novel effects and functions that cannot be attained in bulk form. Given that the electromagnetic responses are a major source of the physical properties of solids, and new gauge structures often appear in correlated electronic systems, we put 'emergent electromagnetism' at the center of Fig. 1.

Hwang, H.Y.

2012-02-16

342

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

343

Autistic phenomena in neurotic patients.  

PubMed

I have described a group of patients who are seemingly successful in their professional and social lives, and who seek analysis ostensibly for professional reasons or for minor difficulties in their relationship. However, sooner or later they reveal phenomena which are strikingly similar to those observed in so-called autistic children. These autistic phenomena are characterized by an almost impenetrable encapsulation of part of the personality, mute and implacable resistance to change, and a lack of real emotional contact either with themselves or the analyst. Progress of the analysis reveals an underlying intense fear of pain, and of death, disintegration or breakdown. These anxieties occur as a reaction to real or feared separation, especially when commitment to analysis deepens. In the case I have described in detail the patient used various projective processes to deflect painful emotions either into other people, including the analyst, or into their own bodies. As a consequence the various objects or organs of the body swell up and became suffused with rage as a result of having to contain the unwanted feelings. This process leads in turn to intense persecutory fears and a heightened sensitivity to the analyst's tone of voice and facial expression. It would seem that the initial hypersensitivity of part of the personality is such as to lead it to anticipate danger to such an extent that it expels feelings even before they reach awareness. The sooner the analyst realizes the existence of this hidden part of the patient the less the danger of the analysis becoming an endless and meaningless intellectual dialogue and the greater the possibilities of the patient achieving a relatively stable equilibrium. Although the analyst has to live through a great deal of anxiety with the patient I feel that ultimately the results make it worth while. PMID:7440079

Klien, S

1980-01-01

344

Turbulent phenomena in protein folding  

NASA Astrophysics Data System (ADS)

Protein folding and hydrodynamic turbulence are two long-standing challenges, in molecular biophysics and fluid dynamics, respectively. The theories of these phenomena have been developed independently and used different formalisms. Here we show that the protein folding flows can be surprisingly similar to turbulent fluid flows. Studying a benchmark model protein (an SH3 domain), we have found that the flows for the slow folding trajectories of the protein, in which a partly formed N- and C-terminal ? sheet hinders the RT loop from attaching to the protein core, have many properties of turbulent flows of a fluid. The flows are analyzed in a three-dimensional (3D) space of collective variables, which are the numbers of native contacts between the terminal ? strands, between the RT loop and the protein core, and the rest of the native contacts. We have found that the flows have fractal nature and are filled with 3D eddies; the latter contain strange attractors, at which the tracer flow paths behave as saddle trajectories. Two regions of the space increment have been observed, in which the flux variations are self-similar with the scaling exponent h=1/3, in surprising agreement with the Kolmogorov inertial range theory of turbulence. In one region, the cascade of protein rearrangements is directed from larger to smaller scales (net folding), and in the other, it is oppositely directed (net unfolding). Folding flows for the fast trajectories are essentially laminar and do not have the property of self-similarity. Based on the results of our study, we infer, and support this inference by simulations, that the origin of the similarity between the protein folding and turbulent motion of a fluid is in a cascade mechanism of structural transformations in the systems that underlies these phenomena.

Kalgin, Igor V.; Chekmarev, Sergei F.

2011-01-01

345

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

346

An In-vacuum Diffractometer for Resonant elastic Soft X-ray Scattering  

SciTech Connect

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 x 10{sup -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){sub 2}CuO{sub 4} and thin film (Ga,Mn)As are shown.

D Hawthorn; F He; L Venema; H Davis; A Achkar; J Zhang; R Sutarto; H Wadati; A Radi; et al.

2011-12-31

347

Silicon nanoparticles formation in annealed SiO/SiO2 multilayers  

NASA Astrophysics Data System (ADS)

We present a study on amorphous SiO/SiO2 superlattice performed by grazing-incidence small-angle X-ray scattering (GISAXS). Amorphous SiO/SiO2 superlattices were prepared by high-vacuum evaporation of 3 nm thin films of SiO and SiO2 (10 layers each) onto Si(1 0 0) substrate. After the deposition, samples were annealed at 1100 C for 1 h in vacuum, yielding to Si nanocrystals formation. Using a Guinier approximation, the shape and the size of the crystals were obtained. The size of the growing nanoparticles in the direction perpendicular to the film surface is well controlled by the bilayer thickness. However, their size varies more significantly in the direction parallel to the film surface.

Kova?evi?, I.; Dub?ek, P.; Duguay, S.; Zorc, H.; Radi?, N.; Pivac, B.; Slaoui, A.; Bernstorff, S.

2007-04-01

348

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

349

Vacuum and beam transport lines: main principles  

Microsoft Academic Search

Some details of vacuum system designs of beam transport lines are presented. The effect of gas desorption on vacuum equilibrium and stability and ion-induced pressure instability in the beam transport lines are discussed. Main vacuum relationships are also given as a basis for understanding the vacuum system configuration of beam transport lines. Residual gas spectra together with specific outgassing rates

J. Pivar?; K. D. Tumanov

1997-01-01

350

MEMS Vacuum Packaging Technology and Applications  

Microsoft Academic Search

Many MEMS (micro electro-mechanic systems) parts have to meet the requirements for vacuum packaging. In vacuum packaging, leakage and gas permeation, which affects the normal function of the components, are major problems. Hermetic sealing is one of the most important technologies for reliable vacuum packaging. In this paper, several hermetic sealing technologies for vacuum packaging was presented, including eutectic bonding,

Jin Yufeng; Zhang Jiaxun

2005-01-01

351

Discharge phenomena associated with a preheated wire explosion in vacuum: Theory and comparison with experiment  

SciTech Connect

This paper presents the experimental and simulation results of electrical explosions of preheated tungsten wires at a current rise time of several tens of nanoseconds and at a current density of {approx}10{sup 8} A/cm{sup 2}. The electrical characteristics of wire explosion (WE) were measured. The image of a wire during the electrical explosion was obtained with the help of a framing camera. The proposed magnetohydrodynamic (MHD) model takes into account different stages of WE, namely, the wire heating and vaporization, the phase transition, and the shunting discharge. Two different mathematical approaches were used for WE simulation at different stages. At the first stage, the simulation included a code describing the wire state. At the second stage, the shunting discharge was simulated together with the wire state. The simulation code includes the set of MHD equations, the equilibrium equation of state (density and temperature-dependent pressure and specific internal energy), electron transport models (density and temperature-dependent electrical conductivity and thermal conductivity), and electric circuit equations. Thermionic emission and vapor ionization initiate the plasma layer, which develops around the wire core and supports the shunting discharge. The calculated waveforms of the wire voltage and current, as well as the velocity of the expanding plasma, are in a good agreement with the experimental data.

Beilis, I. I.; Baksht, R. B. [Electrical Discharge and Plasma Laboratory, Tel Aviv University, 69978 Tel Aviv (Israel); Oreshkin, V. I.; Russkikh, A. G.; Chaikovskii, S. A.; Labetskii, A. Yu.; Ratakhin, N. A.; Shishlov, A. V. [Institute of High Current Electronics, Russian Academy of Science, Tomsk (Russian Federation)

2008-01-15

352

Vacuum Thrust Optimised Expansion Deflection Nozzles  

NASA Astrophysics Data System (ADS)

ED nozzles have long been considered for launch vehicle applications, due to their postulated twin benefits of reduced length and altitude compensating capability. However, the difficulties involved in modelling the inviscid/viscous jet boundaries and associated flow phenomena during wake closure, have prevented the creation of a reliable method for the prediction of the performance characteristics of the type through atmospheric flight. However, if the operating regime of the nozzle is restricted to vacuum conditions (e.g. upper stages, and OTVs, etc), the wake region of the ED nozzle is permanently closed. Under these circumstances, the prediction of the pressure distribution along the viscous/inviscid flow boundary, and the complex interaction of the fluid flows during wake closure, becomes unnecessary. Therefore thrust calculation may be accomplished by conventional techniques, provided reliable methods are available for the prediction of the flow in the throat region (which may be arbitrarily displaced and inclined to the axis of revolution), and estimation of the pressure acting on the base of the central pintle. Prediction of ED nozzle throat flows has been accomplished by the use of CFD techniques, described in a previous paper. The analysis in this paper has been extended to complete nozzles by including a conventional method of characteristics based optimisation routine for the outer shroud contour, and a semi-empirical method for prediction of pintle base pressures. A brief parametric study is presented, outlining the effects of throat configuration (including throat wall radii, and radial displacement and inclination) on the performance of axisymmetric and planar ED nozzles under vacuum conditions. Whilst the method used for base pressure prediction requires several simplifying assumptions which affect the accuracy, results from an ongoing experimental program are reducing this uncertainty. Further as nozzles designed for vacuum operation are likely to have extremely high area ratios to maximise thrust coefficient, the relative magnitude of the pintle base pressure is small compared to the forces generated on the shroud, reducing the sensitivity of overall thrust calculations to errors in base pressure prediction. A comparison of thrust performance of bell and ED nozzles reveals that considerable reductions in length are possible, in the region of 30%. By implication this should result in a significant lowering of system mass. This conclusion is further supported by consideration of the unrealistic worst case scenario, which is the assumption of zero thrust contribution from the pintle. This analysis still produces length savings of over 20% when compared to conventional optimised bell nozzles.

Taylor, N. V.; Hempsell, C. M.

2002-01-01

353

Origin of reverse annealing effect in hydrogen-implanted silicon  

SciTech Connect

In contradiction to conventional damage annealing, thermally annealed H-implanted Si exhibits an increase in damage or reverse annealing behavior, whose mechanism has remained elusive. On the basis of quantitative high resolution transmission electron microscopy combined with channeling Rutherford backscattering analysis, we conclusively elucidate that the reverse annealing effect is due to the nucleation and growth of hydrogen-induce platelets. Platelets are responsible for an increase in the height and width the channeling damage peak following increased isochronal anneals.

Di, Zengfeng [Los Alamos National Laboratory; Nastasi, Michael A [Los Alamos National Laboratory; Wang, Yongqiang [Los Alamos National Laboratory

2009-01-01

354

Origin of reverse annealing effect in hydrogen-implanted silicon  

SciTech Connect

In contradiction to conventional damage annealing, thermally annealed H-implanted Si exhibits an increase in damage or reverse annealing behavior, whose mechanism has remained elusive. In this work, we conclusively elucidate that the reverse annealing effect is due to the nucleation and growth of hydrogen-induced platelets. Platelets are responsible for an increase in the height and width of the channeling damage peak following increased isochronal anneals.

Di, Z. F.; Wang, Y. Q.; Nastasi, M. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Theodore, N. David [Silicon Technology Solutions, Freescale Semiconductor Inc., Tempe, Arizona 85284 (United States)

2010-04-12

355

Electromechanical phenomena in semiconductor nanostructures  

NASA Astrophysics Data System (ADS)

Electromechanical phenomena in semiconductors are still poorly studied from a fundamental and an applied science perspective, even though significant strides have been made in the last decade or so. Indeed, most current electromechanical devices are based on ferroelectric oxides. Yet, the importance of the effect in certain semiconductors is being increasingly recognized. For instance, the magnitude of the electric field in an AlN/GaN nanostructure can reach 1-10 MV/cm. In fact, the basic functioning of an (0001) AlGaN/GaN high electron mobility transistor is due to the two-dimensional electron gas formed at the material interface by the polarization fields. The goal of this review is to inform the reader of some of the recent developments in the field for nanostructures and to point out still open questions. Examples of recent work that involves the piezoelectric and pyroelectric effects in semiconductors include: the study of the optoelectronic properties of III-nitrides quantum wells and dots, the current controversy regarding the importance of the nonlinear piezoelectric effect, energy harvesting using ZnO nanowires as a piezoelectric nanogenerator, the use of piezoelectric materials in surface acoustic wave devices, and the appropriateness of various models for analyzing electromechanical effects. Piezoelectric materials such as GaN and ZnO are gaining more and more importance for energy-related applications; examples include high-brightness light-emitting diodes for white lighting, high-electron mobility transistors, and nanogenerators. Indeed, it remains to be demonstrated whether these materials could be the ideal multifunctional materials. The solutions to these and other related problems will not only lead to a better understanding of the basic physics of these materials, but will validate new characterization tools, and advance the development of new and better devices. We will restrict ourselves to nanostructures in the current article even though the measurements and calculations of the bulk electromechanical coefficients remain challenging. Much of the literature has focused on InGaN/GaN, AlGaN/GaN, ZnMgO/ZnO, and ZnCdO/ZnO quantum wells, and InAs/GaAs and AlGaN/AlN quantum dots for their optoelectronic properties; and work on the bending of nanowires have been mostly for GaN and ZnO nanowires. We hope the present review article will stimulate further research into the field of electromechanical phenomena and help in the development of applications.

Lew Yan Voon, L. C.; Willatzen, M.

2011-02-01

356

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

357

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

358

Asymmetric brightness of transparent organic emitting device with passivation layer by annealing  

NASA Astrophysics Data System (ADS)

We studied transparent organic light emitting diode (TOLED) with semitransparent cathode, Ca-Ag and optical enhanced passivation layer by annealing. The 8-hydroxyquinolatolithium (Liq) passivation layer improves the stability of Ca/Ag double layer, resulting in substantial increase of the efficiency by the enhanced transmittance and change brightness as electrode. Fabricated device was composed as followed structure, glass/ITO/2TNATA/?-NPD/Alq3:C545T (1%)/Bebq2/Ca-Ag. The passivation layer, Liq (40nm) was deposited on the device without broken vacuum before encapsulation with transparent glass sheets. Thermal annealing was carried out in oven at 80oC after encapsulation. At the device without passivation layer, annealing process made device to be deteriorated, such as to increase driving voltage from 6.8 V to 9.0 V at 10 mA/cm2 and to drop efficiency 14.89 cd/A to 10.81 cd/A as bottom view. This drop of properties was caused by oxidation of cathode. However, the organic passivation layer played enough roles to protect oxidation of cathode. The efficiency as bottom side view of device with passivation layer, it can be observed that the efficiency and driving voltage were improved from 13.95 cd/A (@ 6.45 V) to 15.32 cd/A (@ 4.60 V) at 10 mA/cm2 by annealing. Annealing process, in the device with passivation layer, made to increase the asymmetry of brightness through anode and cathode. So the ratio BBot/BTop of the emitted light through each electrode was changed from 2.26 to 4.33.

Lee, Chan-Jae; Choi, Duck-Kyun; Lee, Jeong-No

2010-03-01

359

High-silicon steel produced by hot dipping and diffusion annealing  

NASA Astrophysics Data System (ADS)

Steels with high Si content (up to 6.5% Si) are excellent soft magnetic materials, however, as the Si content is increased, the material becomes extremely brittle and it is very difficult to produce thin sheet by conventional rolling. An alternative production route has been developed through hot dipping in a high Si-bath followed by diffusion annealing. Experiments were carried out in a hot dip simulator using as substrate a steel with 0.35 mm thickness and 3.2% Si. Samples were dipped in an Al-Si hypereutectic bath at 800 C for different times. After dipping, the coating consists of Fe-Al-Si phases and primary silicon crystals within a matrix of eutectic Al-Si. During a first annealing inside the hot dip simulator, diffusion of Si and Al into the substrate and phase transformation occurs in the layer producing a series of ternary intermetallics of the Fe-Si-Al system. A second annealing was performed outside the hot dip simulator under vacuum at 1250 C with different holding times. This diffusion annealing allows the homogenisation of the composition obtaining a homogeneous concentration of 6%-7% Si and/or 2%-5% Al over the thickness in function of the previous hot-dip parameters. The material was characterized by SEM. Magnetic properties were measured and it was shown that the magnetic losses after hot dipping and diffusion annealing were reduced at 50 Hz from 3.7 W/kg (original material) to 0.64 W/kg (1 T), and at 400 Hz from 47 W/kg (original material) to 10 W/kg (1 T).

Ros-Yaez, T.; Houbaert, Y.; Gmez Rodrguez, V.

2002-05-01

360

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

361

Conductance phenomena in microcrystalline cellulose  

NASA Astrophysics Data System (ADS)

We have investigated the conduction phenomena in compacted tablets of cellulose with varying relative humidity (RH) with techniques such as Low Frequency Dielectric Spectroscopy (LFDS) and Transient Current (TC) at room temperature. Two exponential decaying regions in the transient current measurements indicate two ionic species contributing to the conduction mechanism. A high power-law exponent of 9 for the conductance with moisture content has been found. The mobility initially decreases with RH up to monolayer coverage, and further water vapor increases the mobility, indicating a blocking of available positions for the charge carrier ions. When the amount of water molecules present in the tablet increases one order of magnitude, the number of charge carriers increases 5-6 orders of magnitude, suggesting a transition from a power-law increase to a linear effective medium theory for the conduction. The charge carrier dependence on RH suggests that a percolating network of water molecules adsorbed to 6-OH units on the cellulose chain span through the sample. The conductivity mechanisms in cellulose are still not clear.

Nilsson, M.

2006-02-01

362

Understanding empathy and related phenomena.  

PubMed

Over a period of time, the author arrived at a few tentative postulates concerning empathy and related processes based on some of his experiences and observations. The central theme of these postulates is, firstly, that interpersonal interaction is an interaction of the personal-space fields. Secondly, empathy, therapeutic benefit, and the professional stress are all related to the same process of interpersonal interaction. This interaction takes place as an enmeshment of personal spaces of the interacting individuals, and involves transfer of a wide range of information in the affective, cognitive, and other areas. This is because the personal spaces have fieldlike qualities analogous to what Kurt Lewin described. Thus, such phenomena as empathy, therapeutic benefit, professional stress are all consequences of the same process. It is possible to substantiate these postulates by diverse evidences in the published literature. The natural consequences of such an interpersonal interaction are empathic understanding, transfer of mood states (like hope, distress or expectancy), affective states (like anxiety, sadness, anger or hostility), ideas, images and even attitudes and values, etc. This phenomenon of transfer can explain such processes as therapeutic benefit in individual and group settings, professional stress, shared delusions, and even experimenter bias. Whether one becomes aware of such transferred information or not depends upon the intent and sensitivity of the participants. PMID:10415993

Shamasundar, C

1999-01-01

363

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

364

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

365

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

366

Vibrational evidence for chiral recognition phenomena in vacuo  

NASA Astrophysics Data System (ADS)

Molecules and molecular conformations which cannot be superimposed on their mirror image are chiral. Chirality or handedness plays an important role throughout the life sciences. When two molecules interact, they can sense their relative handedness, giving rise to spectroscopic signatures of chiral recognition. This is often mediated by hydrogen bonds, most versatile and directional intermolecular interactions. If the distinction between the homo- and heteroconfigurational pairs of molecules is large enough, chiral discrimination, i.e. differences in abundance may occur. The contact between two flexible, transiently chiral molecules may induce a matching of their handedness, i.e. chirality synchronization. Such phenomena are best studied at low temperatures in vacuum isolation, without perturbing interactions [1]. Structural information on the isolated molecular complexes can be obtained by rotational spectroscopy [2], if there is a sufficient dipole moment. Vibrational spectroscopy [3] provides a more universal, but also more coarse-grained access to these phenomena. Our group has reported the first spectroscopic example of chiral recognition between constitutionally identical molecules in the gas phase [4]. We have found a case of chiral discrimination in tetrameric aggregates of methyl lactate, where the relative configuration controls the hydrogen bond topology [5]. In the case of alcohols, we have observed different degrees of chirality synchronization up to a quantitative chirality matching in dimers of trifluoroethanol [6]. These discoveries became possible through the use of a powerful combination of FTIR spectroscopy and high-throughput, pulsed supersonic nozzle expansions into large vacuum chambers [7]. The isolated and elementary character of the investigated molecular assemblies is favourable for quantum chemical treatments [8]. Valuable benchmarks for the modeling of more complex chiral recognition phenomena are thus established. [1] A. Al-Rabaa, E. Br'eh'eret, F. Lahmani, A. Zehnacker, Chem. Phys. Lett. 1995, 237, 480 [2] J.P.I. Hearn, R.V. Cobley, B.J. Howard, J. Chem. Phys., 2005, 123, 134324; Z. Su, N. Borho, Y. Xu, J. Am. Chem. Soc. 2006, 128, 17126 [3] K. Le Barbu, F. Lahmani, A. Zehnacker, J. Phys. Chem. A, 2002, 106, 6271 [4] N. Borho and M. A. Suhm, Phys. Chem. Chem. Phys., 2002, 4, 2721 [5] N. Borho and M. A. Suhm, Org. Biomol. Chem., 2003, 1, 4351 [6] T. Scharge, T. H"aber, M. A. Suhm, Phys. Chem. Chem. Phys., 2006, 8, 4664 [7] N. Borho, M. A. Suhm, K. Le Barbu-Debus, A. Zehnacker, Phys. Chem. Chem. Phys., 2006, 8, 4449 [8] T. B. Adler, N. Borho, M. Reiher, M. A. Suhm, Angew. Chem. Int. Ed., 2006, 45, 3440

Suhm, Martin A.

2007-06-01

367

Impedances of Laminated Vacuum Chambers  

SciTech Connect

First publications on impedance of laminated vacuum chambers are related to early 70s: those are of S. C. Snowdon [1] and of A. G. Ruggiero [2]; fifteen years later, a revision paper of R. Gluckstern appeared [3]. All the publications were presented as Fermilab preprints, and there is no surprise in that: the Fermilab Booster has its laminated magnets open to the beam. Being in a reasonable mutual agreement, these publications were all devoted to the longitudinal impedance of round vacuum chambers. The transverse impedance and the flat geometry case were addressed in more recent paper of K. Y. Ng [4]. The latest calculations of A. Macridin et al. [5] revealed some disagreement with Ref. [4]; this fact stimulated us to get our own results on that matter. Longitudinal and transverse impendances are derived for round and flat laminated vacuum chambers. Results of this paper agree with Ref. [5].

Burov, A.; Lebedev, V.; /Fermilab

2011-06-22

368

D-Zero Vacuum System  

SciTech Connect

The system pumping speed was calculated by taking the reciprocal of the sum of the reciprocal pump speed and the reciprocal line conductances. The conductances of the pipe were calculated from the following formulas taken from the Varian vacuum manual. This report updates the original to reflect the pumping curves and basic vacuum system characteristics for the purchased components and installed piping of the D-Zero vacuum system. The system consists of two Edward's E2M275 two stage mechanical pumps, a Leybold-Heraeus WSU2000 Blower and three Varian 4' diffusion pumps (one for each cryostat). Individual pump and system pumping speed curves and a diagram of the system is included.

Wintercorn, S.J.; /Fermilab

1986-04-07

369

Mathematical theory of physical vacuum  

NASA Astrophysics Data System (ADS)

This article sets out mathematical basics of unifying fundamental physical theory, with a single postulate of nonvoid physical vacuum. It will be shown that all basic equations of classical electrodynamics, quantum mechanics and gravitation theory could be derived from two nonlinear equations, which define dynamics of physical vacuum in three-dimensional Euclidean space and, in turn, are derived from equations of Newtonian mechanics. Through the characteristics of physical vacuum, namely its density and propagation velocity of various densitys perturbations, such principal physical conceptions as matter and antimatter, electric, magnetic and gravitational fields, velocity of light, electron, photon and other elementary particles, internal energy, mass, charge, spin, quantum properties, Planck constant and fine structure constant will have clear and sane definitions.

Magnitskii, N. A.

2011-06-01

370

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

371

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

372

Observations of the Vacuum Arc and Metal Transfer During Vacuum Consumable Arc Remelting.  

National Technical Information Service (NTIS)

Observations have been made using high speed color photography of the vacuum arc and electrode surfaces during vacuum consumable arc remelting of a maraging steel alloy. Events on the film are coordinated with electrical signals from the vacuum arc. Based...

F. J. Zanner

1979-01-01

373

Modularity optimization by conformational space annealing  

NASA Astrophysics Data System (ADS)

We propose a modularity optimization method, Mod-CSA, based on stochastic global optimization algorithm, conformational space annealing (CSA). Our method outperforms simulated annealing in terms of both efficiency and accuracy, finding higher modularity partitions with less computational resources required. The high modularity values found by our method are higher than, or equal to, the largest values previously reported. In addition, the method can be combined with other heuristic methods, and implemented in parallel fashion, allowing it to be applicable to large graphs with more than 10 000 nodes.

Lee, Juyong; Gross, Steven P.; Lee, Jooyoung

2012-05-01

374

Cooperativity in the annealing of DNA origamis.  

PubMed

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. PMID:23298065

Arbona, Jean-Michel; Aim, Jean-Pierre; Elezgaray, Juan

2013-01-01

375

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

376

Quantum vacuum magneto-optics  

NASA Astrophysics Data System (ADS)

In this article we report on the recent experimental activities concerning the magneto-optics of quantum vacuum performed by our team based at the LNCMI of Toulouse. In particular, we will deal with quantum vacuum Cotton-Mouton and inverse Cotton-Mouton effects which have been predicted in the framework of Quantum electrodynamics. Finally, we will present our experiment on photon oscillations into massive particles in the presence of a magnetic field, an effect that could be a signature of physics beyond the standard model.

Battesti, Rmy; Berceau, Paul; Fouch, Mathilde; Rikken, Geert L. J. A.; Rizzo, Carlo

2013-01-01

377

Global three-neutrino vacuum oscillation fits to the solar and atmospheric anomalies  

SciTech Connect

We determine the three-neutrino mixing and mass parameters that are allowed by the solar and atmospheric neutrino data when vacuum oscillations are responsible for both phenomena. The global fit does not appreciably change the allowed regions for the parameters obtained from effective two-neutrino fits. We discuss how measurements of the solar electron energy spectrum below 6.5 GeV in Super-Kamiokande and seasonal variations in the Super-Kamiokande, {sup 71}Ga, and BOREXINO experiments can distinguish the different solar vacuum solutions. {copyright} {ital 1999} {ital The American Physical Society}

Barger, V. [Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States)]|[Department of Physics, University of Wisconsin, Madison, Wisconsin 53706 (United States); Whisnant, K. [Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States)

1999-05-01

378

Quantum phenomena in disordered conductors  

NASA Astrophysics Data System (ADS)

In this thesis we consider three separate phenomena that arise in disordered conductors. The first part is devoted to the development of the theory of size and disorder dependence in the Kondo effect. We demonstrate that for a thin film of thickness L with mean-free path ? , disorder provides a correction to the Kondo resistivity of the form t0s/kFL ?2 ln T that explains the disorder-induced depression of the Kondo effect observed experimentally in Cu(Fe) films. In the second part, we study the influence of non-magnetic transition element impurities on conventional superconductivity. We find that phonon coupling at impurities counteracts the traditional effects which dominate Tc suppression in the non-magnetic limit. In some cases, we predict that non-magnetic transition metal impurities can actually enhance Tc . We find qualitative agreement between the predicted increase and the experimental data for IV-VI degenerate semiconductors doped with Tl or In. In the third part, we present a simple qualitative model that interpolates between the high and low temperature properties of quasi-1D conductors. We argue that low-temperature transport is well described by localization theory, with a conductance that decays exponentially with the electron dephasing length. This model is shown to be in quantitative agreement with the experimental data on the organic conductor TTT2I3-d . We also show how the low-temperature positive magnetoresistance observed in TTT2I3-d and other quasi-1D conductors can be explained by the role spin-flip scattering plays in the electron dephasing rate.

Martin, Ivar

379

Exponential analysis in physical phenomena  

NASA Astrophysics Data System (ADS)

Many physical phenomena are described by first-order differential equations whose solution is an exponential decay. Determining the time constants and amplitudes of exponential decays from the experimental data is a common task in semiconductor physics (deep level transient spectroscopy), biophysics (fluorescence decay analysis), nuclear physics and chemistry (radioactive decays, nuclear magnetic resonance), chemistry and electrochemistry (reaction kinetics) and medical imaging. This review article discusses the fundamental mathematical limitations of exponential analysis, outlines the critical aspects of acquisition of exponential transients for subsequent analysis, and gives a comprehensive overview of numerical algorithms used in exponential analysis. In the first part of the article the resolution of exponential analysis as a function of noise in input decays is discussed. It is shown that two exponential decays can be resolved in a transient only if the ratio of their time constants is greater than the resolution limit, which can be explicitly calculated from the signal-to-noise ratio in the transient. Although the signal-to-noise ratio is generally limited by the sensitivity of the equipment, it is shown that digitalization of the decays may be a major source of noise. The requirements for type of analog-to-digital converter, number of digitized data points and duration of digitized transients, which must be met to obtain the theoretical resolution limit and to improve stability of the exponential analysis, are formulated. The second part of the review article gives an overview and comparison of major numerical techniques of exponential analysis, such as the nonlinear least squares fit, the Prony method, the method of modulating functions, the method of moments, the Laplace-Pad approximation, the Tikhonov regularization method, the Gardner transformation, the method of maximum entropy and others.

Istratov, Andrei A.; Vyvenko, Oleg F.

1999-02-01

380

Improved zircon fission-track annealing model based on reevaluation of annealing data  

NASA Astrophysics Data System (ADS)

The thermal recovery (annealing) of mineral structure modified by the passage of fission fragments has long been studied by the etching technique. In minerals like apatite and zircon, the annealing kinetics are fairly well constrained from the hour to the million-year timescale and have been described by empirical and semi-empirical equations. On the other hand, laboratory experiments, in which ion beams interact with minerals and synthetic ceramics, have shown that there is a threshold temperature beyond which thermal recovery impedes ion-induced amorphization. In this work, it is assumed that this behavior can be extended to the annealing of fission tracks in minerals. It is proposed that there is a threshold temperature, T 0, beyond which fission tracks are erased within a time t 0, which is independent of the current state of lattice deformation. This implies that iso-annealing curves should converge to a fanning point in the Arrhenius pseudo-space (ln t vs. 1/ T). Based on the proposed hypothesis, and laboratory and geological data, annealing equations are reevaluated. The geological timescale estimations of a model arising from this study are discussed through the calculation of partial annealing zone and closure temperature, and comparison with geological sample constraints found in literature. It is shown that the predictions given by this model are closer to field data on closure temperature and partial annealing zone than predictions given by previous models.

Guedes, S.; Moreira, P. A. F. P.; Devanathan, R.; Weber, W. J.; Hadler, J. C.

2013-02-01

381

Improved zircon fission-track annealing model based on reevaluation of annealing data  

SciTech Connect

The thermal recovery (annealing) of mineral structure modified by the passage of fission fragments has long been studied by the etching technique. In minerals like apatite and zircon, the annealing kinetics are fairly well constrained from the hour to the million-year timescale and have been described by empirical and semi-empirical equations. On the other hand, laboratory experiments, in which ion beams interact with minerals and synthetic ceramics, have shown that there is a threshold temperature beyond which thermal recovery impedes ion-induced amorphization. In this work, it is assumed that this behavior can be extended to the annealing of fission tracks in minerals. It is proposed that there is a threshold temperature, T0, beyond which fission tracks are erased within a time t0, which is independent of the current state of lattice deformation. This implies that iso-annealing curves should converge to a fanning point in the Arrhenius pseudo-space (ln t vs. 1/T). Based on the proposed hypothesis, and laboratory and geological data, annealing equations are reevaluated. The geological timescale estimations of a model arising from this study are discussed through the calculation of partial annealing zone and closure temperature, and comparison with geological sample constraints found in literature. It is shown that the predictions given by this model are closer to field data on closure temperature and partial annealing zone than predictions given by previous models.

Guedes, Sandro [Instituto de Fisica Gleb Wataghin, Unicamp, Brazil; Moreira, Pedro A.F.P. [Universidade Estadual de Campinas, Sao Paulo; Devanathan, Ram [Pacific Northwest National Laboratory (PNNL); Weber, William J [ORNL; Hadler, Julio C [Instituto de Fisica Gleb Wataghin, Unicamp, Brazil

2013-01-01

382

Elimination of undemonstrable phenomena in the EMTP  

Microsoft Academic Search

This paper discusses the undemonstrable phenomena that can occur when the EMTP is used for simulation of some types of networks, consisting of power electronics, and\\/or voltage-, current controlled elements. The synchronous response procedure (SRP) is suggested for elimination of these phenomena. Meanwhile the advantage of the critical damping adjustment technique (CDA) for approximate simulation of the impulse function is

Jiming Lin

1998-01-01

383

Luminous phenomena and earthquakes in southern Washington  

Microsoft Academic Search

Summary Luminous phenomena, mostly nocturnal lights, are associated with very small earthquakes in southern Washington state. The phenomena seem to be electrical in nature, related to earthquake lights, and tend to occur when the locus of earthquake activity moves across an active fault in an area of compressional stress.

J. S. Derr; M. A. Persinger

1986-01-01

384

The microstructural response of mill-annealed and solution-annealed INCONEL 600 to heat treatment  

NASA Astrophysics Data System (ADS)

Samples of INCONEL* 600 were examined in the mill-annealed and solution-annealed states, and after isothermal annealing at 400 C and 650 C. The corrosion behavior of the samples was examined, analytical electron microscopy was used to determine the microstructures present and the chemistry of grain boundaries, and Auger electron spectroscopy was used to measure grain boundary segregation. Samples of different alloys in the mill-annealed state were found to have quite different microstructures, with Cr-rich M7C3 carbides occurring either along grain boundaries or in intragranular sheets. The corrosion behavior of the samples correlated well with the occurrence of grain boundary chromium depletion. Solution annealing at 1190 C caused dissolution of all carbides, whereas at 1100 C the carbides either dissolved or the grain boundaries moved away from the carbides, depending upon alloy carbon content. Low-temperature annealing at 400 C had little effect on millannealed or fully solutionized samples, but in samples with intragranular carbides present, the grain boundaries moved until intersecting or adjacent to the carbides. Isothermal annealing at 650 C caused carbide nucleation and growth at grain boundaries in fully solutionized samples. Chromium depletion at grain boundaries accompanied carbide precipitation, with a minimum chromium level of 6 wt pct achieved after 5 hours. Healing was found to occur after 100 hours. Solution-annealed samples with intragranular carbides present had more rapid corrosion kinetics since the grain boundaries moved back to the existing carbides. Thermodynamic analysis of the chromium-depletion process showed good agreement with experimental measurements. The Auger results found only boron present at grain boundaries in the mill-annealed state. Aged samples had boron, nitrogen, and phosphorus present, with phosphorus and nitrogen segregating to the greatest extent. The kinetics of phosphorus segregation are much slower at 400 C compared with 650 C.

Hall, Ernest L.; Briant, Clyde L.

1985-07-01

385

Single-crystal diamond plate liftoff achieved by ion implantation and subsequent annealing  

SciTech Connect

We describe a new method for removing thin, large area sheets of diamond from bulk or homoepitaxial diamond crystals. This method consists of an ion implantation step, followed by a selective etching procedure. High energy (4--5 MeV) implantation of carbon or oxygen ions creates a well-defined layer of damaged diamond that is buried at a controlled depth below the surface. For C implantations, this layer is graphitized by annealing in vacuum, and then etched in either an acid solution, or by heating at 550--600 [degree]C in oxygen. This process successfully lifts off the diamond plate above the graphite layer. For O implantations of a suitable dose (3[times]10[sup 17] cm[sup [minus]2] or greater), the liftoff is achieved by annealing in vacuum or flowing oxygen. In this case, the O required for etching of the graphitic layer is also supplied internally by the implantation. This liftoff method, combined with well-established homoepitaxial growth processes, has considerable potential for the fabrication of large area single crystalline diamond sheets.

Parikh, N.R.; Hunn, J.D.; McGucken, E.; Swanson, M.L. (University of North Carolina, Chapel Hill, North Carolina 27599-3255 (United States)); White, C.W. (Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6048 (United States)); Rudder, R.A.; Malta, D.P.; Posthill, J.B.; Markunas, R.J. (Research Triangle Institute, Research Triangle Park, North Carolina 27709-2194 (United States))

1992-12-28

386

Understanding the Physics of changing mass phenomena  

NASA Astrophysics Data System (ADS)

Changing mass phenomena, like a falling chain or a bungee jumper, might give surprising results, even for experienced physicists. They have resulted in hot discussions in journals, in which for instance Physics professors claim the impossibility of an acceleration larger then g in case of a bungee jumper. These phenomena are also interesting as topics for challenging student projects, and used as such by Dutch high school students. I will take these phenomena as the context in which I like to demonstrate the possibilities of ICT in the learning process of physics. Especially dynamical modeling enables us to describe these phenomena in an elegant way and with knowledge of high school mathematics. Furthermore tools for video-analysis and data from measurements with sensors allow us to study the phenomena in experiments. This example demonstrates the level of implementation of ICT in Physics Education in The Netherlands [1].

Ellermeijer, A. L.

2008-05-01

387

Minkowski vacuum stress tensor fluctuations  

Microsoft Academic Search

We study the fluctuations of the stress tensor for a massless scalar field in two- and four-dimensional Minkowski spacetime in the vacuum state. Covariant expressions for the stress tensor correlation function are obtained as sums of derivatives of a scalar function. These expressions allow one to express spacetime averages of the correlation function as finite integrals. We also study the

Thomas A. Roman; L. H. Ford

2005-01-01

388

Vacuum Distillation of Americium Metal.  

National Technical Information Service (NTIS)

High-purity americium metal has been distilled in multigram quantities from a plutonium-americium alloy. The procedure consisted of a two-stage vacuum distillation carried out at 1200 exp 0 C and 10 exp -6 torr pressure. Four batches of americium metal we...

J. W. Berry J. B. Knighton C. A. Nannie

1982-01-01

389

Quantum Vacuum Structure and Cosmology  

SciTech Connect

Contemporary physics faces three great riddles that lie at the intersection of quantum theory, particle physics and cosmology. They are: (1) The expansion of the universe is accelerating - an extra factor of two appears in the size; (2) Zero-point fluctuations do not gravitate - a matter of 120 orders of magnitude; and (3) The 'True' quantum vacuum state does not gravitate. The latter two are explicitly problems related to the interpretation and the physical role and relation of the quantum vacuum with and in general relativity. Their resolution may require a major advance in our formulation and understanding of a common unified approach to quantum physics and gravity. To achieve this goal we must develop an experimental basis and much of the discussion we present is devoted to this task. In the following, we examine the observations and the theory contributing to the current framework comprising these riddles. We consider an interpretation of the first riddle within the context of the universe's quantum vacuum state, and propose an experimental concept to probe the vacuum state of the universe.

Rafelski, Johann; Labun, Lance; Hadad, Yaron; /Arizona U. /Munich U.; Chen, Pisin; /Taiwan, Natl. Taiwan U. /KIPAC, Menlo Park /SLAC

2011-12-05

390

Vacuum-injection-molding processing  

SciTech Connect

An improved processing technique for the manufacture of glass or glass-ceramic headers has been developed. Vacuum-injection molding is a relatively easy processing technique that has been used successfully in the fabrication of several different advantages in certain applications over the present fabrication process which uses glass preforms.

Kramer, D.P.; Massey, R.T.

1982-01-01

391

A simple triggered vacuum gap  

Microsoft Academic Search

A simple triggered vacuum gap has previously been described by the authors in this journal (see ibid., vol.5, 415, 1972). Further studies have resulted in improvement of the performance with regard to sensitivity and consistency of the trigger characteristics and immunity from bridging due to metal particles eroded from the arc. The earlier design suffered from rather frequent bridging of

N. Vidyardhi; R. S. N. Rau

1973-01-01

392

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

393

Vacuum pumping system for TPX  

SciTech Connect

The design of the vacuum pumping system for is discussed, and progress in the research and development effort is summarized. The TPX vacuum system will use cryocondensation pumps for hydrogenic divertor pumping and turbomolecular pumps for torus evacuation, glow discharge cleaning, and deuterium-helium divertor pumping. A set of poloidally and toroidally symmetric vacuum ducts will connect the torus to the vacuum pumps; this symmetry will permit simultaneous equal pumping speed at the upper and lower divertors, and it will minimize toroidal variations in divertor pumping speed. At the divertor plena the total cryocondensation pumping speed for D{sub 2} at 65 C and 1 mTorr will be 80 m{sup 3}/s and the total turbomolecular pumping speed for D{sub 2} or He at 65 C and 1 mTorr will be 18 m{sup 3}/s; the system will be compatible with upgrades to improve pumping speed, to operate continuously, or to operate with D-T fuel. The cryocondensation pumps will be custom units capable of completing a low temperature regeneration cycle in 1 hour.

St. Onge, K.D.

1995-12-31

394

Vacuum Pyrolysis of Sodium Stearate.  

National Technical Information Service (NTIS)

Vacuum pyrolysis of sodium stearate was studied to provide useful information for Green River oil shale pyrolysis. Sodium stearate is a typical compound of carboxylic acid salts amounting to 3.6% of total organic materials in the oil shale by methanol ext...

S. L. Chong

1985-01-01

395

Sizing the vacuum chambers conservatively  

SciTech Connect

This note will examine many different scenarios, both optimistic and pessimistic, for the performance of the B Factory. The primary reason for this is to establish limits for the emittances in the two rings. This information will be needed to ensure that the vacuum chambers are sized to permit the maximum flexibility. 3 refs., 3 tabs.

Hutton, A.

1990-05-21

396

APS storage ring vacuum system  

Microsoft Academic Search

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.

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

1991-01-01

397

Forest landscape management modeling using simulated annealing  

Microsoft Academic Search

This paper presents a new landscape management model using a simulated annealing approach. The model is capable of achieving target landscape structure, in the form of composition and configuration objectives, in a near optimal fashion by spatially and temporally scheduling treatment interventions. Management objectives and constraints are identified in an objective function. Penalty cost functions for each objective establish common

Emin Z. Baskent; Glen A. Jordan

2002-01-01

398

Drawing graphs nicely using simulated annealing  

Microsoft Academic Search

The paradigm of simulated annealing is applied to the problem of drawing graphs nicely. Our algorithm deals with general undirected graphs with straight-line edges, and employs several simple criteria for the aesthetic quality of the result. The algorithm is flexible, in that the relative weights of the criteria can be changed. For graphs of modest size it produces good results,

Ron Davidson; David Harel

1996-01-01

399

High resolution image reconstruction by simulated annealing  

Microsoft Academic Search

This paper presents a new technique for reconstructing a high resolution image from a sequence of lower resolution frames. The new technique is based on a Monte-Carlo type simulated annealing algorithm in which the reconstruction task is recast as an optimisation problem. The proposed method has the added advantage of not requiring the registration of the displacement of each low

Thanachart Numnonda; Mark Andrews; Ramakrishna Kakarala

1994-01-01

400

High resolution image reconstruction by simulated annealing  

NASA Astrophysics Data System (ADS)

This paper presents a new technique for reconstructing a high resolution image from a sequence of lower resolution frames. The new technique is based on a Monte-Carlo type simulated annealing algorithm in which the reconstruction task is recast as an optimisation problem. The proposed method has the added advantage of not requiring the registration of the displacement of each low resolution frame.

Numnonda, Thanachart; Andrews, Mark; Kakarala, Ramakrishna

1994-05-01

401

Annealed and quenched inhomogeneous cellular automata (INCA)  

Microsoft Academic Search

A probabilistic one-dimensional cellular automaton model by Domany and Kinzel is mapped into an inhomogeneous cellular automaton with the Boolean functions XOR and AND as transition rules. Wolfram's classification is recovered by varying the frequency of these two simple rules and by quenching or annealing the inhomogeneity. In particular, class 4 is related to critical behavior in directed percolation. Also,

G. Y. Vichniac; P. Tamayo; H. Hartman

1986-01-01

402

Annealing of gold nanostructures sputtered on polytetrafluoroethylene.  

PubMed

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. PMID:22078024

Siegel, Jakub; Krajcar, Robert; Kolsk, Zde?ka; Hnatowicz, Vladimr; Svor?k, Vclav

2011-11-11

403

Simulated annealing: A tool for operational research  

Microsoft Academic Search

This paper describes the Simulated Annealing algorithm and the physical analogy on which it is based. Some significant theoretical results are presented before describing how the algorithm may be implemented and some of the choices facing the user of this method. An overview is given of the experience of experimenters with SA and some suggestions are made for ways to

R. W. Eglese

1990-01-01

404

Quantum Adiabatic Evolution Algorithms versus Simulated Annealing  

Microsoft Academic Search

We explain why quantum adiabatic evolution and simulated annealing perform similarly in certain examples of searching for the minimum of a cost function of n bits. In these examples each bit is treated symmetrically so the cost function depends only on the Hamming weight of the n bits. We also give two examples, closely related to these, where the similarity

Edward Farhi; Jeffrey Goldstone; Sam Gutmann

2002-01-01

405

Annealing of nuclear reactor pressure vessels  

Microsoft Academic Search

The neutron embrittlement that occurs in the beltline of reactor pressure vessels (RPV) can be managed by various techniques such as fuel management, but only thermal annealing can reverse the effects and result in a restoration of RPV beltline material toughness. The US Nuclear Regulatory Commission has recently revised the Code of Federal Regulations to include the use of thermal

M. G Vassilaros; M. E Mayfield; K. R Wichman

1998-01-01

406

Superconductor-insulator transition on annealed complex networks  

NASA Astrophysics Data System (ADS)

Cuprates show multiphase and multiscale complexity that has hindered physicists search for the mechanism of high Tc for many years. Recently the interest has been addressed to a possible optimum inhomogeneity of dopants, defects, and interstitials, and the structural scale invariance of dopants detected by scanning micro-x-ray diffraction has been reported to promote the critical temperature. In order to shed light on critical phenomena on granular materials, here we propose a stylized model capturing the essential characteristics of the superconducting-insulator transition of a highly dynamical, heterogeneous granular material: the random transverse Ising model (RTIM) on annealed complex network. We show that when the networks encode for high heterogeneity of the expected degrees described by a power-law distribution, the critical temperature for the onset of the superconducting phase diverges to infinity as the power-law exponent ? of the expected degree distribution is less than 3, i.e., ?<3. Moreover we investigate the case in which the critical state of the electronic background is triggered by an external parameter g that determines an exponential cutoff in the power-law expected degree distribution characterized by an exponent ?. We find that for g=gc the critical temperature for the superconducting-insulator transition has a maximum if ?>3 and diverges if ?<3.

Bianconi, Ginestra

2012-06-01

407

HIGH PRODUCTIVITY VACUUM BLASTING SYSTEM  

SciTech Connect

The objective of this project is to improve the productivity and lower the expense of existing vacuum blasting technology. This technology is used to remove radioactive contamination, PCBs, and lead-based paint and provides worker protection by continuously recycling the material and dust for the decontamination tasks. The proposed work would increase the cleaning rate and provide safe and cost-effective decontamination of the DOE sites. This work focuses on redesigning and improving existing vacuum blasting technology including blast head nozzles, ergonomic handling of the blast head by reducing its weight; brush-ring design, vacuum level regulator, efficiency of the dust separator, and operational control sensors. The redesign is expected to enhance the productivity and economy of the vacuum blasting system by at least 50% over current vacuum blasting systems. There are three phases in the project. Phase I consists of developing and testing mathematical models. Phase II consists of pre-prototype design and fabrication and pre-prototype unit testing. Phase III consists of prototype design and field verification testing. In phase I, mathematical models are developed and analyzed for the nozzle, blast head, wind curtain, and dust separator, first as individual devices and then combined as an integrated model. This allows study of respective airflow and design parameters. The Contractor shall, based on the results of the mathematical modeling studies, design experimental models of the components and test these models. In addition, the Contractor shall develop sensors to detect the relationship of the blast head to the blast surfaces and controls to minimize the dependency on an operator's skill and judgment to obtain optimum positioning, as well as real-time characterization sensors to determine as the blast head is moving the depth to which coatings must be removed, thereby improving production and minimizing waste. In phase II, the Contractor shall design and construct a pre-prototype of the nozzle, blast head with wind curtain, sensors, and dust separator and test this system to assess the performance of the new design under controlled conditions at the contractor's facility. In phase III, the Contractor shall design and construct a prototype of the High Productivity Vacuum Blasting System, based on the results of the pre-prototype design and testing performed. This unit will be a full-scale prototype and will be tested at a designated Department of Energy (DOE) facility. Based on the results, the system performance, the productivity, and the economy of the improved vacuum blasting system will be evaluated.

William S. McPhee

1999-05-31

408

Cold-Cathodes for Sensors and Vacuum Microelectronics  

SciTech Connect

The aim of this laboratory-directed research and development project was to study amorphous carbon (a-C) thin films for eventual cold-cathode electron emitter applications. The development of robust, cold-cathode emitters are likely to have significant implications for modern technology and possibly launch a new industry: vacuum micro-electronics (VME). The potential impact of VME on Sandia`s National Security missions, such as defense against military threats and economic challenges, is profound. VME enables new microsensors and intrinsically radiation-hard electronics compatible with MOSFET and IMEM technologies. Furthermore, VME is expected to result in a breakthrough technology for the development of high-visibility, low-power flat-panel displays. This work covers four important research areas. First, the authors studied the nature of the C-C bonding structures within these a-C thin films. Second, they determined the changes in the film structures resulting from thermal annealing to simulate the effects of device processing on a-C properties. Third, they performed detailed electrical transport measurements as a function of annealing temperature to correlate changes in transport properties with structural changes and to propose a model for transport in these a-C materials with implications on the nature of electron emission. Finally, they used scanning atom probes to determine important aspects on the nature of emission in a-C.

Siegal, M.P.; Sullivan, J.P.; Tallant, D.R.; Simpson, R.L. [Sandia National Labs., Albuquerque, NM (United States); DiNardo, N.J.; Mercer, T.W. [Drexel Univ., Philadelphia, PA (United States). Dept. of Physics and Astronomy; Martinez-Miranda, L.J. [Univ. of Maryland, College Park, MD (United States). Dept. of Materials Science and Engineering

1998-05-01

409

Tribology-related space mechanism anomalies and the newly constructed high-vacuum mechanism test facilities in NASDA  

Microsoft Academic Search

In the past many functional anomalies of mechanisms and mechanical components have been experienced on board spacecraft and their launch vehicles. Such anomalies sometimes lead to the total loss of the spacecraft. Among the major causes of mechanical anomalies, vacuum tribology-related malfunctions have received central attention in Japan due to the continued occurrence of spacecraft failures. Phenomena such as the

Akira Takano

1999-01-01

410

Excimer pulsed laser deposition and annealing of YSZ nanometric films on Si substrates  

NASA Astrophysics Data System (ADS)

We report experimental results obtained for electrical and structural characteristics of yttria-stabilised zirconia (YSZ) thin films deposited by pulsed laser deposition (PLD) on Si substrates at room temperature. Some samples were submitted to thermal treatments in different ambient atmospheres (vacuum, N2 and O2) at a moderate temperature. The effects of thermal treatments on the film electrical properties were studied by C V and I V measurements. Structural characteristics were obtained by X-ray diffraction (XRD), X-ray reflectivity (XRR) and transmission electron microscopy (TEM) analyses. The as-deposited film was amorphous with an in-depth non-uniform density. The annealed films became polycrystalline with a more uniform density. The sample annealed in O2 was uniform over all the thickness. Electrical characterisation showed large hysteresis, high leakage current and positive charges trapped in the oxide in the as-deposited film. Post-deposition annealing, especially in O2 atmosphere, improved considerably the electrical properties of the films.

Caricato, A. P.; Barucca, G.; di Cristoforo, A.; Leggieri, G.; Luches, A.; Majni, G.; Martino, M.; Mengucci, P.

2005-07-01

411

On the induced microstructure changes of the amorphous carbon nitride films during annealing  

NASA Astrophysics Data System (ADS)

The analysis of the stress release and structural changes caused by postdeposition thermal annealing of amorphous carbon nitride thin films (a-CNx) has been carried out. The a-CNx films were deposited on Si (100) using reactive radio frequency (rf) magnetron sputtering of a high-purity graphite target in a pure nitrogen plasma under various different rf powers. Combined Fourier transform infrared (FTIR), Raman spectroscopy, transmission spectroscopy, photothermal deflexion spectroscopy, and residual stress measurements were used to fully characterize the films. Annealing of the samples in vacuum at temperature up to 600 C produces changes in their structural properties and the intrinsic stress. These changes are found to be strongly dependent on both the deposition conditions and microstructure changes occurring within the films during heating. FTIR spectra showed the existence of N-C sp3, N=C sp2, and CtrpbndN triple bonds in the deposited films. The analysis of the spectra versus annealing temperature (TA) reveals that the major microstructure changes are the reorganization of the C-N and C-C configurations, without significant densification of the deposited films. The Raman features combined to the optical measurements reveal that this progressive graphitization of the material, with increasing TA, is accompanied by a higher disorder form of C sp2 sites. These results are used to describe the stress variation that accompanies the nitrogen evolution within the deposited films.

Lejeune, M.; Durand-Drouhin, O.; Charvet, S.; Zeinert, A.; Benlahsen, M.

2007-06-01

412

Behaviour of Copper In Annealed Cu/Sio2/Si Systems For On-Chip Interconnections  

NASA Astrophysics Data System (ADS)

The electrical and structural properties of thin copper films attract increasing attention nowadays because of the use for on-chip interconnections. The main advantages of copper are the excellent conductivity and the relatively high stability against electro migration damaging. Interdiffusion at the copper/silicon interface can be a remarkable drawback of the interconnection quality even at room temperature which leads to the use of barrier layers between copper and silicon in technical applications. Often, thermal annealing of the as-deposited copper films is required to ensure proper process integration. In the present paper, Copper thin films of thickness 100 nm are deposited on SiO2/Si by ionized metal plasma deposition method. Then samples are annealed at different temperatures under high vacuum condition. The behavior of copper and the mechanism of compound formation studied at different temperatures, using scanning electron microscopy SEM, X-ray diffraction XRD and four point probe method. Diffusion of Cu into SiO2/Si layer start at 550 C and form CuxSiy. Oxidation of Cu is also take place at high temperature annealing.

Htwe, Thant Zin; Latt, Khin Maung

2010-01-01

413

Crystallinity and properties of C60 nanotubes improved by annealing and alcohol-soaking  

NASA Astrophysics Data System (ADS)

Well-uniformed C60 nanotubes were grown at -20 C with irradiation of red light using C60-saturated pyridine solution and isopropyl alcohol by a liquid-liquid interfacial precipitation method without ultrasonic pulverization. We attempted to improve their crystallinity by two post-treatments; thermal annealing and alcohol-soaking. The crystallinity of as-grown and dried C60 nanotubes, which was poor due to the evaporation of solvent molecules from crystals in the drying process, was improved by annealing around 220 C for 5 hours in vacuum. Dramatic improvement of crystallinity of as-grown samples was achieved by soaking into methanol and then drying in air. Raman, infrared and X-ray diffraction results suggest that the methanol-soaked samples exhibit a solvated tetragonal structure. The crystallinity improved by methanol-soaking did not degrade after removal of methanol molecules from samples by thermal annealing. Photo-polymerization of the structurally-improved C60 nanotubes was examined to investigate an effect of crystallinity on the polymerization kinetics.

Naito, K.; Matsuishi, K.

2009-04-01

414

Surface morphology evolution of amorphous Fe Si layers upon thermal annealing  

NASA Astrophysics Data System (ADS)

Changes in the surface morphology of ion-beam-synthesized amorphous Fe-Si layers after rapid thermal annealing (RTA) and furnace annealing (FA) were investigated using atomic force microscopy and transmission electron microscopy. Completely amorphous Fe-Si layers were formed by Fe implantation at a dosage of 5 1015 cm-2 using a metal vapour vacuum arc ion source under 80 kV extraction voltage and cryogenic temperature. After RTA at 850 C, ?-FeSi2 precipitates in Si are completely aggregated from this amorphous Fe-Si layer and the surface of the implanted layer remains flat. To date, no obvious photoluminescence (PL) spectrum has been reported from RTA treated ?-FeSi2 precipitates. However, after annealing at 850 C for 40 s, high-quality ?-FeSi2 precipitates in Si are obtained which clearly show 1.5 m PL at 80 K for the first time. Even though additional long-term FA at 850 C can enhance PL intensity to a limited extent, the longer thermal treatment induces the outdiffusion of ?-FeSi2 precipitates and degrades the surface flatness.

Sun, C. M.; Tsang, H. K.; Wong, S. P.; Ke, N.; Hark, S. K.

2008-04-01

415

Transfer-free graphene synthesis on insulating substrates via agglomeration phenomena of catalytic nickel films  

NASA Astrophysics Data System (ADS)

Graphene layers were synthesized by annealing amorphous carbon (a-C) thin films on Ni/SiO2/Si(111) substrates grown using pulse arc plasma deposition. Although the graphene layers were formed by catalytic reaction between a-C films and Ni metals, they were observed to be directly on the insulating SiO2/Si substrates with island-shaped metallic particles. These particles presumably resulted from agglomeration phenomena of thin Ni films at a high temperature. We speculated that the agglomeration phenomena allowed the graphene formation on SiO2/Si substrates. It was also confirmed that the particle size and graphene layer thickness depend on the starting Ni thickness.

Banno, Kazuya; Mizuno, Masaya; Fujita, Kazuhisa; Kubo, Toshiharu; Miyoshi, Makoto; Egawa, Takashi; Soga, Tetsuo

2013-08-01

416

Thermally induced formation of SiC nanoparticles from Si/C/Si multilayers deposited by ultra-high-vacuum ion beam sputtering  

NASA Astrophysics Data System (ADS)

A novel approach for the formation of SiC nanoparticles (np-SiC) is reported. Deposition of Si/C/Si multilayers on Si(100) wafers by ultra-high-vacuum ion beam sputtering was followed by thermal annealing in vacuum for conversion into SiC nanoparticles. The annealing temperature significantly affected the size, density, and distribution of np-SiC. No nanoparticles were formed for multilayers annealed at 500 C, while a few particles started to appear when the annealing temperature was increased to 700 C. At an annealing temperature of 900 C, many small SiC nanoparticles, of several tens of nanometres, surrounding larger submicron ones appeared with a particle density approximately 16 times higher than that observed at 700 C. The higher the annealing temperature was, the larger the nanoparticle size, and the higher the density. The higher superheating at 900 C increased the amount of stable nuclei, and resulted in a higher particle density compared to that at 700 C. These particles grew larger at 900 C to reduce the total surface energy of smaller particles due to the higher atomic mobility and growth rate. The increased free energy of stacking defects during particle growth will limit the size of large particles, leaving many smaller particles surrounding the large ones. A mechanism for the np-SiC formation is proposed in this paper.

Chung, Chen-Kuei; Wu, Bo-Hsiung

2006-07-01

417

Interfacial polarization phenomena in organic molecular films.  

PubMed

Electrostatic phenomena occurring at the interface between metal/organic and organic/organic materials are discussed from the viewpoint of dielectrics physics. Focusing on two important origins of surface polarization phenomena, orientational ordering of polar molecules and displacement of excess charges at the interface, surface polarization phenomena of organic thin films are discussed. To define the orientational order of polar molecules, orientational order parameters are introduced, and surface polarization due to the alignment of dipoles is expressed. The generation of Maxwell displacement current (MDC) and optical second harmonic generation (SHG) that are specific for surface organic monomolecular films are discussed, and some experimental evidence are shown. As an extension of the concept of surface Fermi level introduced to discuss the electrostatic phenomena due to electron transfer at the interface between metal-organic insulators, the surface Fermi level is extended to the discussion on the electrostatic phenomena of organic semiconductor materials on metals. In this paper, some experimental evidence of surface polarization originating from polar molecules and displacement of excess charges are shown. After that, with consideration of these surface phenomena, single electron tunneling of organic films are briefly discussed in association with surface polarization phenomena. PMID:17761247

Iwamoto, Mitsumasa; Manaka, Takaaki

2006-01-26

418

Development of a Vacuum Superinsulation Panel.  

National Technical Information Service (NTIS)

A vacuum superinsulation system with pressure resistant, temperature resistant thermal insulation of high efficiency was developed. Vacuum-tight sealing, compression and evacuation of powder filling as well as special material investigations were performe...

H. Timm D. Seefeldt C. Nitze

1983-01-01

419

Development of a Vacuum Superinsulation Panel.  

National Technical Information Service (NTIS)

After completion of the investigations the vacuum-insulated panel is available as prototype. The aim of the investigations was to optimize and to finalize the vacuum superinsulation system with regard to a pressure-resistant, temperature-resistant thermal...

H. Timm D. Seefeldt C. Nitze

1983-01-01

420

Materials for ultra-high vacuum  

SciTech Connect

This report discusses materials for use in ultrahigh vacuum systems of 1 {times} 10{sup {minus}9} Torr or lower. The author briefly discusses alloys, solders, insulators and joining methods for vacuum systems. (JDL)

Lee, G.

1989-08-15

421

14 CFR 29.1433 - Vacuum systems.  

Code of Federal Regulations, 2010 CFR

...pressure in the discharge lines from the vacuum air pump when the delivery temperature of the air becomes unsafe. (b) Each vacuum air system line and fitting on the discharge side of the pump that might contain flammable...

2010-01-01

422

14 CFR 29.1433 - Vacuum systems.  

Code of Federal Regulations, 2010 CFR

...pressure in the discharge lines from the vacuum air pump when the delivery temperature of the air becomes unsafe. (b) Each vacuum air system line and fitting on the discharge side of the pump that might contain flammable...

2009-01-01

423

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

424

Synchronization Phenomena and Epoch Filter of Electroencephalogram  

NASA Astrophysics Data System (ADS)

Nonlinear electrophysiological synchronization phenomena in the brain, such as event-related (de)synchronization, long distance synchronization, and phase-reset, have received much attention in neuroscience over the last decade. These phenomena contain more electrical than physiological keywords and actually require electrical techniques to capture with electroencephalography (EEG). For instance, epoch filters, which have just recently been proposed, allow us to investigate such phenomena. Moreover, epoch filters are still developing and would hopefully generate a new paradigm in neuroscience from an electrical engineering viewpoint. Consequently, electrical engineers could be interested in EEG once again or from now on.

Matani, Ayumu

425

The History of Vacuum Regulation Technology  

Microsoft Academic Search

An inordinate amount of time, money and anguish has been invested in changing the ways that vacuum is controlled in milking machines. These extraordinary efforts have not resulted in a commensurate improvement in milking performance. There are two fundamental methods of influencing the vacuum in the milking machine: 1) a device to regulate 'system' vacuum, usually located near the receiver

Douglas J. Reinemann

426

Drying leather with vacuum and toggling sequentially  

Technology Transfer Automated Retrieval System (TEKTRAN)

We investigated a drying method that will enable leather to be dried under vacuum and stretch sequentially to improve area yield. Vacuum drying offers fast speed at a low temperature, which would be advantageous to heat-vulnerable chrome-free leather. Adding a toggle action after vacuum drying cou...

427

High rate vacuum deposition of polymer electrolytes  

Microsoft Academic Search

Two new, high rate, vacuum processes have been developed for the deposition of polymer electrolyte layers on wide web substrates. One method involves the vacuum extrusion of monomer salt solutions followed by e-beam or ultraviolet (UV) curing. The second method involves the vacuum flash evaporation of the monomer salt solution followed by e-beam or UV curing. Each method is compatible

J. D. Affinito; M. E. Gross; C. A. Coronado; G. C. Dunham; P. M. Martin

1996-01-01

428

Development of a vacuum superinsulation panel  

Microsoft Academic Search

A vacuum superinsulation system with pressure resistant, temperature resistant thermal insulation of high efficiency was developed. Vacuum-tight sealing, compression and evacuation of powder filling as well as special material investigations were performed. Applications include coverings of linings with high temperature and\\/or pressure requirements. A vacuum insulated panel prototype was built.

H. Timm; D. Seefeldt; C. Nitze

1983-01-01

429

Rotary bayonets for cryogenic and vacuum service  

Microsoft Academic Search

Rotary bayonets were designed, tested, and installed for liquid nitrogen, liquid argon, and vacuum service. This paper will present the design, testing, and service record for two sizes of vacuum jacketed cryogenic rotary bayonets and two sizes of vacuum service rotary bayonets. Materials used in construction provide electrical isolation across the bayonet joint. The joint permits 360 degrees of rotation

R. A. Rucinski; K. D. Dixon; R. Krasa; K. J. Krempetz; G. T. Mulholland; G. R. Trotter; J. B. Urbin

1993-01-01

430

Increasing electric standoff between conductors in vacuum  

Microsoft Academic Search

Pulsed power systems have limitations on power delivery. One limitation is the breakdown potential between conductive surfaces in vacuum. In a vacuum breakdown, a vacuum arc is generated between the surfaces. The microscopic limit on the breakdown potential is at the onset of field emission from the surface. The microscopic field for the onset of field emission is in excess

Donald Pellinen

2007-01-01

431

Charging and Discharge in Vacuum and Space  

Microsoft Academic Search

Success of vacuum electronic devices often depends on secure electrical insulation of the components. The presence of solid insulator significantly decreases the insulation strength of the vacuum apparatus. Charging of solid insulator in the pre-breakdown process enhances the electric field near the triple junction and leads to electrical discharge. Electrostatic discharge (ESD) on spacecraft surface is similar to other vacuum

Mengu Cho

2007-01-01

432

14 CFR 25.1433 - Vacuum systems.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Vacuum systems. 25.1433 Section...Miscellaneous Equipment § 25.1433 Vacuum systems. There must be means...pressure in the discharge lines from the vacuum air pump when the delivery temperature...

2010-01-01

433

14 CFR 25.1433 - Vacuum systems.  

Code of Federal Regulations, 2010 CFR

...2009-01-01 2009-01-01 false Vacuum systems. 25.1433 Section...Miscellaneous Equipment § 25.1433 Vacuum systems. There must be means...pressure in the discharge lines from the vacuum air pump when the delivery temperature...

2009-01-01

434

AUTOMATED MALLEABLE ANNEALING OVENS SLOWLY HEAT AND COOL CASTINGS AS ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

AUTOMATED MALLEABLE ANNEALING OVENS SLOWLY HEAT AND COOL CASTINGS AS THEY MOVE IN BINS ALONG TRACKS IN THE OVEN BOTTOM IN THE MALLEABLE ANNEALING BUILDING. THIS PROCESS TRANSFORMS BRITTLE WHITE IRON CASTINGS INTO SOFTER, STRONGER MALLEABLE IRON. - Stockham Pipe & Fittings Company, Malleable Annealing Building, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

435

Effect of annealing on the hydrolysis of sago starch granules  

Microsoft Academic Search

Sago starch annealed at varying temperatures, time intervals and pH was used to study granule hydrolysis by a glucoamylase (AMG) and ?-amylase (Termamyl) mixture. Differential scanning calorimetry (DSC) indicated that there was a relationship between the extent of annealing and starch granule hydrolysis. Enthalpy of gelatinisation of annealed starch granules remained unchanged, suggesting that no gelatinisation had occurred. The degree

W. J. Wang; A. D. Powell; C. G. Oates

1997-01-01

436

49 CFR 570.56 - Vacuum brake assist unit and vacuum brake system.  

Code of Federal Regulations, 2010 CFR

... 6 2010-10-01 2010-10-01 false Vacuum brake assist unit and vacuum brake system. 570.56 Section 570.56 ...GVWR of More Than 10,000 Pounds § 570.56 Vacuum brake assist unit and vacuum brake system....

2010-10-01

437

49 CFR 570.56 - Vacuum brake assist unit and vacuum brake system.  

Code of Federal Regulations, 2010 CFR

... 6 2009-10-01 2009-10-01 false Vacuum brake assist unit and vacuum brake system. 570.56 Section 570.56 ...GVWR of More Than 10,000 Pounds § 570.56 Vacuum brake assist unit and vacuum brake system....

2009-10-01

438

Deposition of high k ZrO2 thin films by high vacuum electron beam evaporation at room temperature  

Microsoft Academic Search

Amorphous zirconium oxide (ZrO2) films have been deposited on P type Si (100) substrates using High Vacuum Electron Beam Evaporation (HVEBE) at room temperature. The chemical composition of the films was investigated by X-ray photoelectron spectroscopy (XPS). The experimental results reveal that the dominating chemical state of zirconia thin films is fully oxidized state, Zr4+, no matter whether annealed in

Ninglin Zhang; Qing Wan; Zhitang Song; Qinwo Shen; Chenglu Lin

2001-01-01

439

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

440

Exploring the Scope of Controlling Quantum Phenomena.  

National Technical Information Service (NTIS)

During the period of the grant an interrelated set of studies were performed in the general domain of control over quantum dynamics phenomena. A prime focus was on establishing the basic principles of quantum control and their experimental implications. T...

H. Rabitz

2012-01-01

441

Transport Phenomena During Equiaxed Solidification of Alloys.  

National Technical Information Service (NTIS)

Recent progress in modeling of transport phenomena during dendritic alloy solidification is reviewed. Starting from the basic theorems of volume averaging, a general multiphase modeling framework is outlined. This framework allows for the incorporation of...

C. Beckermann H. C. deGroh

1997-01-01

442

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

443

Wave and Fracture Phenomena in Impacted Ceramics.  

National Technical Information Service (NTIS)

An optical measuring technique in combination with high speed photography is provided to solve the problem of this contract, the investigation of wave and fracture phenomena in opaque ceramic materials. Surface disturbances caused by these mechanical even...

S. Winkler

1988-01-01

444

Astronomical Phenomena for the Year 1990.  

National Technical Information Service (NTIS)

This publication contains information extracted from the Astronomical Almanac for the Year 1990. Dates and times of planetary and lunar phenomena and other astronomical data of general interest are presented.

1988-01-01

445

Modeling of fundamental phenomena in welds.  

National Technical Information Service (NTIS)

Recent advances in the mathematical modeling of fundamental phenomena in welds are summarized. State-of-the-art mathematical models, advances in computational techniques, emerging high-performance computers, and experimental validation techniques have pro...

T. Zacharia J. M. Vitek J. A. Goldak T. A. DebRoy M. Rappaz

1993-01-01

446

Computer Modeling and Animation of Natural Phenomena.  

National Technical Information Service (NTIS)

3D graphics animation is increasingly used in movies and virtual reality computer games to produce realistic visual simulations of physical and natural phenomena. The animation of diffuse liquids such as gases is an indispensable component in such special...

D. S. Ebert J. S. Schpok

2005-01-01

447

Analysis of nuclear reactor instability phenomena  

SciTech Connect

The phenomena known as density-wave instability often occurs in phase change systems, such as boiling water nuclear reactors (BWRS). Our current understanding of density-wave oscillations is in fairly good shape for linear phenomena (eg, the onset of instabilities) but is not very advanced for non-linear phenomena [Lahey and Podowski, 1989]. In particular, limit cycle and chaotic instability modes are not well understood in boiling systems such as current and advanced generation BWRs (eg, SBWR). In particular, the SBWR relies on natural circulation and is thus inherently prone to problems with density-wave instabilities. The purpose of this research is to develop a quantitative understanding of nonlinear nuclear-coupled density-wave instability phenomena in BWRS. This research builds on the work of Achard et al [1985] and Clausse et al [1991] who showed, respectively, that Hopf bifurcations and chaotic oscillations may occur in boiling systems.

Lahey, R.T. Jr.

1993-01-01

448

Taming the {alpha}-vacuum  

SciTech Connect

An interacting scalar field theory in de Sitter space appears to be nonrenormalizable for a generic {alpha}-vacuum state. This pathology arises since the usual propagator used allows for a constructive interference among propagators in loop corrections, which produces divergences that are not proportional to standard counterterms. This interference can be avoided by defining a new propagator for the {alpha}-vacuum based on a generalized time-ordering prescription. The generating functional associated with this propagator contains a source that couples to the field both at a point and at its antipode. To one loop order, we show that a set of theories with very general antipodal interactions is causal and renormalizable.

Collins, Hael; Holman, R. [Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States)

2004-10-15

449

Decoherence delays false vacuum decay  

NASA Astrophysics Data System (ADS)

We show that gravitational interactions between massless thermal modes and a nucleating Coleman-de Luccia bubble may lead to efficient decoherence and strongly suppress metastable vacuum decay for bubbles that are small compared to the Hubble radius. The vacuum decay rate including gravity and thermal photon interactions has the exponential scaling \\Gamma \\sim \\Gamma _{CDL}^{2}, where ?CDL is the Coleman-de Luccia decay rate neglecting photon interactions. For the lowest metastable initial state an efficient quantum Zeno effect occurs due to thermal radiation of temperatures as low as the de Sitter temperature. This strong decoherence effect is a consequence of gravitational interactions with light external mode. We argue that efficient decoherence does not occur for the case of Hawking-Moss decay. This observation is consistent with requirements set by Poincar recurrence in de Sitter space.

Bachlechner, Thomas C.

2013-05-01

450

HIGH PRODUCTIVITY VACUUM BLASTING SYSTEM  

SciTech Connect

The Department of Energy (DOE) needs improved technologies to decontaminate large areas of both concrete and steel surfaces. The technology should have high operational efficiency, minimize exposures to workers, and produce low levels of secondary waste. In order to meet the DOE's needs, an applied research and development project for the improvement of a current decontamination technology, Vacuum Blasting, is proposed. The objective of this project is to improve the productivity and lower the expense of the existing vacuum blasting technology which has been widely used in DOE sites for removing radioactive contamination, PCBs, and lead-based paint. The proposed work would increase the productivity rate and provide safe and cost-effective decontamination of the DOE sites.

William S. McPhee

2001-08-31

451

Mirror fusion vacuum technology developments  

SciTech Connect

Magnetic Mirror Fusion experiments, such as MFTF-B+T (Mirror Fusion Test Facility-B, Tritium Upgrade) and foreseeable follow-on devices, have operational and maintenance requirements that have not yet been fully demonstrated. Among those associated with vacuum technology are the very-high continuous-pumping speeds, 10/sup 7/ to 10/sup 8/ l/s for D/sub 2/, T/sub 2/ and, to a lesser extent, He; the early detection of water leaks from the very-high heat-flux neutral-beam dumps and the detection and location of leaks in the superconducting magnets not protected by guard vacuums. Possible solutions to these problems have been identified and considerable progress has been made toward successfully demonstrating their feasibility.

Batzer, T.H.; Call, W.R.

1983-11-21

452

Structural and magnetic properties of annealed FePt/Ag/FePt thin films  

NASA Astrophysics Data System (ADS)

Layer stacks of FePt(15 nm)/Ag(x)/FePt(15 nm) with various Ag interlayer thicknesses (x = 0, 3, and 30 nm) were deposited at room temperature onto SiO2(100 nm)/Si(0 0 1) substrates. These films were post-annealed in a temperature range of 100 C-900 C for 30 s under high vacuum condition. The influence of the Ag interlayer on the L10(FePt)FCT phase formation and its related structural and magnetic properties were investigated. The onset of chemical ordering of FePt single layers is observed at annealing temperatures between 600 C and 700 C. Increasing the Ag interlayer thickness to 30 nm reduces the ordering temperature of the L10(FePt)FCT phase formation by about 100 C. Higher annealing temperatures lead to a further increase in volume fraction of the ordered L10(FePt)FCT phase but also to the diffusion of Ag towards the free surface as probed by secondary neutral mass spectrometry. In addition, due to the limited solvability of Ag into the FePt phase, Ag is expected to be located at the grain boundaries. The increasing volume fraction of the L10(FePt)FCT phase is also reflected in the increasing coercivity of the films which reaches values of up to 19 kOe after annealing at 900 C. Furthermore, in this case similar M-H hysteresis loop were recorded when the field is applied in the film plane and perpendicular to it. This isotropic behavior is in agreement with the coexistence of L10 ordered grains which are randomly oriented.

Pavlova, O. P.; Verbitska, T. I.; Vladymyrskyi, I. A.; Sidorenko, S. I.; Katona, G. L.; Beke, D. L.; Beddies, G.; Albrecht, M.; Makogon, I. M.

2013-02-01

453

New phenomena in pulsed FIR gas lasers  

Microsoft Academic Search

New phenomena occur when pulsed far-infrared (FIR) gas lasers are pumped with the pulses of 10 ?m-hybrid-CO2 lasers truncated within 10 ps as well as when truncating directly the FIR laser pulses with the first FIR plasma shutter developed in our laboratory. These new phenomena include, e.g. new interrelations between superradiance, swept-gain superradiance and Raman emission, anticorrelated fluctuations of pump

D. P. Scherrer; J. Knittel; D. B. Moix; M. O. Baumgartner; F. K. Kneubhl

1995-01-01

454

New phenomena in pulsed fir gas lasers  

Microsoft Academic Search

New phenomena occur when pulsed far-infrared (FIR) gas lasers are pumped with the pulses of 10 mum-hybrid-CO2 lasers truncated within 10 ps as well as when truncating directly the FIR laser pulses with the first FIR plasma shutter developed in our laboratory. These new phenomena include, e.g. new interrelations between superradiance, swept-gain superradiance and Raman emission, anticorrelated fluctuations of pump

D. P. Scherrer; J. Knittel; D. B. Moix; M. O. Baumgartner; F. K. Kneubhl

1995-01-01

455

Knowledge based prediction of nonlinear phenomena  

Microsoft Academic Search

A pervasive task in decision making lies in the prediction of unknown phenomena. In the past, the majority of decision support\\u000a tools has addressed linear phenomena or simple nonlinear tasks such as discriminatory analysis. However, recent advances in\\u000a nonlinear theory and software techniques suggest the feasibility of developing generalized tools for analyzing nonlinear signals\\u000a incorporating chaotic features. The goal of

S. H. Kim

2000-01-01

456

Vacuum distillation of americium metal  

Microsoft Academic Search

High-purity americium metal has been distilled in multigram quantities from a plutonium-americium alloy. The procedure consisted of a two-stage vacuum distillation carried out at 1200°C and 10⁻⁶ torr pressure. Four batches of americium metal were produced ranging in weight from 13.3 grams to 54.1 grams. The purity of the americium product ranged from 99.27 to 99.79%.

J. W. Berry; J. B. Knighton; C. A. Nannie

1982-01-01

457

Quantum vacuum and accelerated expansion  

NASA Astrophysics Data System (ADS)

A new approach to extraction of quantum vacuum energy, in the context of the accelerated expansion, is proposed, and it is shown that experimentally realistic orders of values can be derived. The idea has been implemented in the framework of the Friedmann-Lematre-Robertson-Walker geometry in the language of the effective action in the relativistic formalism of Schwinger's proper time and Seeley-DeWitt's heat kernel expansion.

Broda, B.; Szanecki, M.

458

Vacuum Ultraviolet Irradiation of Polymers  

Microsoft Academic Search

The interest in incoherent sources for wavelength-selective photochemistry has increased lately, but little is still known about the behavior of polymers when exposed to far UV and vacuum UV (VUV) radiation. The same dearth of information exists regarding UV (VUV) radiation emitted by low-pressure plasmas during polymer treatment. In order to study VUV-UV effects on several polymers (polyethylene - PE,

A. C. Fozza; J. E. Klemberg-Sapieha; Michael R. Wertheimer

1999-01-01

459

Vacuum stability of Standard Model++  

NASA Astrophysics Data System (ADS)

The latest results of the ATLAS and CMS experiments point to a preferred narrow Higgs mass range (m_h \\simeq 124 - 126 GeV) in which the effective potential of the Standard Model (SM) develops a vacuum instability at a scale 10^{9} -10^{11} GeV, with the precise scale depending on the precise value of the top quark mass and the strong coupling constant. Motivated by this experimental situation, we present here a detailed investigation about the stability of the SM^{++} vacuum, which is characterized by a simple extension of the SM obtained by adding to the scalar sector a complex SU(2) singlet that has the quantum numbers of the right-handed neutrino, H", and to the gauge sector an U(1) that is broken by the vacuum expectation value of H". We derive the complete set of renormalization group equations at one loop. We then pursue a numerical study of the system to determine the triviality and vacuum stability bounds, using a scan of 10^4 random set of points to fix the initial conditions. We show that, if there is no mixing in the scalar sector, the top Yukawa coupling drives the quartic Higgs coupling to negative values in the ultraviolet and, as for the SM, the effective potential develops an instability below the Planck scale. However, for a mixing angle -0.35 \\alt \\alpha \\alt -0.02 or 0.01 \\alt \\alpha \\alt 0.35, with the new scalar mass in the range 500 GeV \\alt m_{h"} \\alt 8 TeV, the SM^{++} ground state can be absolutely stable up to the Planck scale. These results are largely independent of TeV-scale free parameters in the model: the mass of the non-anomalous U(1) gauge boson and its branching fractions.

Anchordoqui, Luis A.; Antoniadis, Ignatios; Goldberg, Haim; Huang, Xing; Lst, Dieter; Taylor, Tomasz R.; Vlcek, Brian

2013-02-01

460

Vacuum barrier for excimer lasers  

DOEpatents

This invention is comprised of 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 yearns impregnated with epoxy. The barrier is stronger than conventional foil barriers, and allows greater electron throughput.

Shurter, R.P.

1990-10-10

461

Vacuum pyrolysis of sodium stearate  

Microsoft Academic Search

Vacuum pyrolysis of sodium stearate was studied to provide useful information for Green River oil shale pyrolysis. Sodium stearate is a typical compound of carboxylic acid salts amounting to 3.6% of total organic materials in the oil shale by methanol extraction. Sodium stearate contained in a stainless steel miniature reactor was heated at 450°C in a fluidized sand bath. Pyrolysis

Chong

1985-01-01

462

Measurement of the accumulation of water ice on optical components in cryogenic vacuum environments  

NASA Astrophysics Data System (ADS)

An experiment was performed to study and measure the deposition of water (H2O) ice on optical component surfaces under high-vacuum cryogenic conditions. Water was introduced into a cryogenic vacuum chamber via a hydrated molecular sieve zeolite housed in a valved external chamber, through an effusion cell, and impinged upon a quartz-crystal microbalance (QCM) and first-surface gold-plated mirror. A laser and photodiode setup external to the vacuum chamber monitored the multiple-beam interference reflectance of the ice-mirror configuration while the QCM measured the mass deposition. Data acquired and analyzed from this experiment indicate that water ice under these conditions accumulates on optical component surfaces as a thin film up to thicknesses over 45 microns and can be detected and measured by nonintrusive optical methods based upon multiple-beam interference phenomena. The QCM, a well-established measurement technique, was used to validate the interferometer.

Moeller, Trevor M.; Smith, L. Montgomery; Collins, Frank G.; Labello, Jesse M.; Rogers, James P.; Lowry, Heard S.; Crider, Dustin H.

2012-10-01

463

Holographic Description of Vacuum Bubbles  

NASA Astrophysics Data System (ADS)

We discuss a holographic description of vacuum bubbles, with possible implications for a consistent description of the multiverse. In particular, we elaborate on the recent observation by Maldacena, that the interior of AdS bubbles can be described in terms of CFT degrees of freedom living on the worldsheet of the bubble wall. We consider the scattering of bulk gravitons in the ambient parent vacuum, off the bubble wall. In the dual description, the transmission coefficient is interpreted as the probability that a graviton is absorbed by the worldsheet CFT degrees of freedom. The result is in agreement with intuitive expectations. Conformal invariance is not exact in this setup, and the leading corrections due to the IR and UV cut-offs are displayed. Aside from bulk scattering states, we find that when a bubble nucleates within a parent dS vacuum, there is a zero mode of the graviton which describes lower dimensional gravity with a finite Newton's constant. This massless graviton lives within one Hubble radius away from the bubble wall. Possible implications for a fully holographic description of the inflating multiverse are briefly discussed.

Garriga, J.

464

Iterated maps for annealed Boolean networks.  

PubMed

Boolean networks are used to study the large-scale properties of nonlinear systems and are mainly applied to model genetic regulatory networks. A statistical method called the annealed approximation is commonly used to examine the dynamical properties of randomly generated Boolean networks that are created with selected statistical features. However, in the literature there are several variations of the annealed approximation. These approximations cannot be interchangeably used in all cases due to different background assumptions. In this paper, we present the so-called four-state model, derive the different approximations from this model, and make the differences and connections between these approximations explicit. As an application of the presented results, we study the properties of the Boolean networks that are constructed with random functions, canalizing functions, and regulatory functions found in the biological literature. PMID:17155130

Kesseli, Juha; Rm, Pauli; Yli-Harja, Olli

2006-10-05

465

Annealing Vs. Invasion in Phage ? Recombination  

PubMed Central

Genetic recombination catalyzed by ?'s Red pathway was studied in rec(+) and recA mutant bacteria by examining both intracellular ? DNA and mature progeny particles. Recombination of nonreplicating phage chromosomes was induced by double-strand breaks delivered at unique sites in vivo. In rec(+) cells, cutting only one chromosome gave nearly maximal stimulation of recombination; the recombinants formed contained relatively short hybrid regions, suggesting strand invasion. In contrast, in recA mutant cells, cutting the two parental chromosomes at non-allelic sites was required for maximal stimulation; the recombinants formed tended to be hybrid over the entire region between the two cuts, implying strand annealing. We conclude that, in the absence of RecA and the presence of non-allelic DNA ends, the Red pathway of ? catalyzes recombination primarily by annealing.

Stahl, M. M.; Thomason, L.; Poteete, A. R.; Tarkowski, T.; Kuzminov, A.; Stahl, F. W.

1997-01-01

466

Shock, post-shock annealing, and post-annealing shock in ureilites  

NASA Astrophysics Data System (ADS)

The thermal and shock histories of ureilites can be divided into four periods: 1) formation, 2) initial shock, 3) post-shock annealing, and 4) post-annealing shock. Period 1 occurred 4.55 Ga ago when ureilites formed by melting chondritic material. Impact events during period 2 caused silicate darkening, undulose to mosaic extinction in olivines, and the formation of diamond, lonsdaleite, and chaoite from indigenous carbonaceous material. Alkali-rich fine-grained silicates may have been introduced by impact injection into ureilites during this period. About 57% of the ureilites were unchanged after period 2. During period 3 events, impact-induced annealing caused previously mosaicized olivine grains to become aggregates of small unstrained crystals. Some ureilites experienced reduction as FeO at the edges of olivine grains reacted with C from the matrix. Annealing may also be responsible for coarsening of graphite in a few ureilites, forming euhedral-appearing, idioblastic crystals. Orthopyroxene in Meteorite Hills (MET) 78008 may have formed from pigeonite by annealing during this period. The Rb-Sr internal isochron age of 4.0 Ga for MET 78008 probably dates the annealing event. At this late date, impacts are the only viable heat source. About 36% of ureilites experienced period 3 events, but remained unchanged afterwards. During period 4, 7% of the ureilites were shocked again, as is evident in the polymict breccia, Elephant Moraine (EET) 83309. This rock contains annealed mosaicized olivine aggregates composed of small individual olivine crystals that exhibit undulose extinction. Ureilites may have formed by impact-melting chondritic material on a primitive body with heterogeneous O isotopes. Plagioclase was preferentially lost from the system due to its low impedance to shock compression. Brief melting and rapid burial minimized the escape of planetary-type noble gases from the ureilitic melts. Incomplete separation of metal from silicates during impact melting left ureilites with relatively high concentrations of trace siderophile elements.

Rubin, Alan E.

2006-01-01

467

Bifurcations in mean-field-theory annealing  

Microsoft Academic Search

In this paper, we investigate bifurcation processes for the mean-field-theory (MFT) annealing applied to traveling-salesman problems (TSPs). Due to the symmetries of the TSP free energy function, some special bifurcations occur: cyclic symmetry breaking bifurcations and reverse symmetry breaking bifurcations. Saddle-node bifurcations also occur. Which type of bifurcation occurs depends on the symmetry of the eigenvector that corresponds to the

Masa-Aki Sato; Shin Ishii

1996-01-01

468

Electroluminescence from annealed ZnO nanowires  

Microsoft Academic Search

We report the effect of thermal annealing on the room-temperature electroluminescence in vertically oriented ZnO nanowires. Ultra-violet luminescence around 390 nm and a broad defect-related band centered at 620 nm are observed. The ZnO nanowires are grown in electrodeposition on SnO2-coated glass substrates, employing a technique that is suitable for large-area applications. The nanowires are robustly encapsulated in thin polymer

R. Konenkamp; R. Word; M. Godinez; A. Nadarajah

2006-01-01

469

Durability of simulated DWPF annealed glasses  

SciTech Connect

Simulated high-level waste glass samples of the DWPF projected compositions were annealed at various times and temperatures in order to develop time-temperature-transformation diagrams. These heat treated glasses were subjected to the Product Consistency Test (PCT) to evaluate glass durability. The B, Li, and Na concentrations in the leachate (the PCT results) were compared to the PCT results of the Environmental Assessment benchmark glass. Durability as a function of glass composition and crystallinity was also examined.

Andrews, M.K.; Cicero, C.A.; Marra, S.L.; Beam, D.C.

1993-03-01

470

A Theoretical Framework for Simulated Annealing  

Microsoft Academic Search

Simulated Annealing has been a very successful general algorithm for the solution of large, complex combinatorial optimization\\u000a problems. Since its introduction, several applications in different fields of engineering, such as integrated circuit placement,\\u000a optimal encoding, resource allocation, logic synthesis, have been developed. In parallel, theoretical studies have been focusing\\u000a on the reasons for the excellent behavior of the algorithm. This

Fabio Romeo; Alberto L. Sangiovanni-vincentelli

1991-01-01

471

Experimental studies of light emission phenomena in superconducting RF cavities  

NASA Astrophysics Data System (ADS)

Experimental studies of light emission phenomena in superconducting RF cavities, which we categorize under the general heading of cavity lights, are described. The cavity lights data, which were obtained using a small CCD video camera, were collected in a series of nine experimental runs ranging from 1/2 to 2 h in duration. The video data were recorded on a standard VHS tape. As the runs progressed, additional instrumentation was added. For the last three runs a LabVIEW-controlled data acquisition system was included. These runs furnish evidence for several, possibly related, light emission phenomena. The most intriguing of these is what appear to be small luminous objects ?1.5 mm in size, freely moving about in the vacuum space, generally without wall contact, as verified by reflections of the tracks in the cavity walls. In addition, on a number of occasions, these objects were observed to bounce off of the cavity walls. The wall-bounce aspect of most of these events was clearly confirmed by pre-bounce and post-bounce reflections concurrent with the tracks. In one of the later runs, a mode of behavior was observed that was qualitatively different from anything observed in the earlier runs. Perhaps the most perplexing aspect of this new mode was the observation of as many as seven luminous objects arrayed in what might be described as a macromolecular formation, coherently moving about in the interior of the cavity for extended periods of time, evidently without any wall contact. It is suggested that these mobile luminous objects are without explanation within the realm of established physics. Some remarks about more exotic theoretical possibilities are made, and future plans are discussed.

Anthony, P. L.; Delayen, J. R.; Fryberger, D.; Goree, W. S.; Mammosser, J.; Szalata, Z. M.; Weisend, J. G.

2009-12-01

472

Experimental Studies of Light Emission Phenomena in Superconducting RF Cavitites  

SciTech Connect

Experimental studies of light emission phenomena in superconducting RF cavities, which we categorize under the general heading of cavity lights, are described. The cavity lights data, which were obtained using a small CCD video camera, were collected in a series of nine experimental runs ranging from {approx} 1/2 to {approx} 2 h in duration. The video data were recorded on a standard VHS tape. As the runs progressed, additional instrumentation was added. For the last three runs a LabVIEW controlled data acquisition system was included. These runs furnish evidence for several, possibly related, light emission phenomena. The most intriguing of these is what appear to be small luminous objects {le} 1.5 mm in size, freely moving about in the vacuum space, generally without wall contact, as verified by reflections of the tracks in the cavity walls. In addition, on a number of occasions, these objects were observed to bounce off of the cavity walls. The wall-bounce aspect of most of these events was clearly confirmed by pre-bounce and post-bounce reflections concurrent with the tracks. In one of the later runs, a mode of behavior was observed that was qualitatively different from anything observed in the earlier runs. Perhaps the most perplexing aspect of this new mode was the observation of as many as seven luminous objects arrayed in what might be described as a macromolecular formation, coherently moving about in the interior of the cavity for extended periods of time, evidently without any wall contact. It is suggested that these mobile luminous objects are without explanation within the realm of established physics. Some remarks about more exotic theoretical possibilities are made, and future plans are discussed.

Anthony, P.L.; /SLAC; Delayen, J.R.; /Jefferson Lab; Fryberger, D.; /SLAC; Goree, W.S.; Mammosser, J.; /Jefferson Lab /SNS Project, Oak Ridge; Szalata, Z.M.; II, J.G.Weisend /SLAC

2009-08-04

473

Hfq proximity and orientation controls RNA annealing  

PubMed Central

Regulation of bacterial gene networks by small non-coding RNAs (sRNAs) requires base pairing with messenger RNA (mRNA) targets, which is facilitated by Hfq protein. Hfq is recruited to sRNAs and mRNAs through U-rich- and A-rich-binding sites, respectively, but their distance from the sRNAmRNA complementary region varies widely among different genes. To determine whether distance and binding orientation affect Hfqs chaperone function, we engineered toy RNAs containing strong Hfq-binding sites at defined distances from the complementary target site. We show that RNA annealing is fastest when the distal face of Hfq binds an A-rich sequence immediately 3? of the target. This recruitment advantage is lost when Hfq binds >20?nt away from the target, but is partially restored by secondary structure that shortens this distance. Although recruitment through Hfqs distal face accelerates RNA annealing, tight binding of six Us to Hfqs proximal face inhibits annealing. Finally, we show that ectopic A-rich motifs dramatically accelerate base pairing between DsrA sRNA and a minimal rpoS mRNA in the presence of Hfq, demonstrating that proximity and orientation predict the activity of Hfq on long RNAs.

Panja, Subrata; Woodson, Sarah A.

2012-01-01

474

Vacuum Technology and Standardization-An Update  

NASA Astrophysics Data System (ADS)

Vacuum technology has been vital for the progress in almost every field of modern industrial & scientific research and technological developments. Research in this field is therefore important for the rapid progress in other sophisticated technologies. The modern society require precise know-how of vacuum metrology for its complex and sophisticated manufacturing processes and research activities. Accuracy in vacuum measurements is therefore an essential need for every application. The required accuracy is achieved with the help of well-calibrated vacuum gauges and this is possible only, if there exist proper vacuum standards of required range and accuracy. In this paper, a brief review of recently developed different vacuum standards, namely Standard Mercury Manometer, Standard Volume Expansion System and Standard Orifice Flow System will be presented, employed for the calibration of low, medium and high vacuum gauges respectively. Our recently developed standards are simple in design, least in vibration & degassing rate with desired accuracy, ease of operation and cost effective.

Akram, H. M.; Rashid, H.

2011-06-01

475

The correlation of damping capacity with grain-boundary precipitates in FeCr-based damping alloys annealed at high temperature  

Microsoft Academic Search

We report the damping capacity measurements and grain-boundary (GB) precipitates observations on a set of four FeCr-based ferromagnetic damping alloys annealed at 1473K. The alloys were prepared by vacuum induction melt furnace of which each cast ingot weighed 15kg. The technique of inverted torsion pendulum was employed to measure the damping capacity, and a field emission scanning electron microscope (FESEM)

Weiguo Wang; Bangxin Zhou

2004-01-01

476

Rapid-thermal-annealing surface treatment for restoring the intrinsic properties of graphene field-effect transistors  

NASA Astrophysics Data System (ADS)

Graphene field-effect transistors (GFETs) were fabricated by photolithography and lift-off processes, and subsequently heated in a rapid-thermal-annealing (RTA) apparatus at temperatures (TA) from 200 to 400? C for 10 min under nitrogen to eliminate the residues adsorbed on the graphene during the GFET fabrication processes. Raman-scattering, current-voltage (I-V), and sheet resistance measurements showed that, after annealing at 250? C, graphene in GFETs regained its intrinsic properties, such as very small intensity ratios of D to G and G to 2D Raman bands, a symmetric I-V curve with respect to 0 V, and very low sheet resistance. Atomic force microscopy images and height profiles also showed that the surface roughness of graphene was almost minimized at TA = 250? C. By annealing at 250? C, the electron and hole mobilities reached their maxima of 4587 and 4605 cm2 V-1 s-1, respectively, the highest ever reported for chemical-vapor-deposition-grown graphene. Annealing was also performed under vacuum or hydrogen, but this was not so effective as under nitrogen. These results suggest that the RTA technique is very useful for eliminating the surface residues of graphene in GFETs, in that it employs a relatively low thermal budget of 250? C and 10 min.

Jang, Chan Wook; Kim, Ju Hwan; Kim, Jong Min; Shin, Dong Hee; Kim, Sung; Choi, Suk-Ho

2013-10-01

477

Rapid-thermal-annealing surface treatment for restoring the intrinsic properties of graphene field-effect transistors.  

PubMed

Graphene field-effect transistors (GFETs) were fabricated by photolithography and lift-off processes, and subsequently heated in a rapid-thermal-annealing (RTA) apparatus at temperatures (TA) from 200 to 400? C for 10min under nitrogen to eliminate the residues adsorbed on the graphene during the GFET fabrication processes. Raman