Single-phase and two-phase anaerobic digestion of fruit and vegetable waste: Comparison of start-up, reactor stability and process performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ganesh, Rangaraj; Torrijos, Michel, E-mail: michel.torrijos@supagro.inra.fr; Sousbie, Philippe

Highlights: • Single-phase and two-phase systems were compared for fruit and vegetable waste digestion. • Single-phase digestion produced a methane yield of 0.45 m{sup 3} CH{sub 4}/kg VS and 83% VS removal. • Substrate solubilization was high in acidification conditions at 7.0 kg VS/m{sup 3} d and pH 5.5–6.2. • Energy yield was lower by 33% for two-phase system compared to the single-phase system. • Simple and straight-forward operation favored single phase process over two-phase process. - Abstract: Single-phase and two-phase digestion of fruit and vegetable waste were studied to compare reactor start-up, reactor stability and performance (methane yield, volatilemore » solids reduction and energy yield). The single-phase reactor (SPR) was a conventional reactor operated at a low loading rate (maximum of 3.5 kg VS/m{sup 3} d), while the two-phase system consisted of an acidification reactor (TPAR) and a methanogenic reactor (TPMR). The TPAR was inoculated with methanogenic sludge similar to the SPR, but was operated with step-wise increase in the loading rate and with total recirculation of reactor solids to convert it into acidification sludge. Before each feeding, part of the sludge from TPAR was centrifuged, the centrifuge liquid (solubilized products) was fed to the TPMR and centrifuged solids were recycled back to the reactor. Single-phase digestion produced a methane yield of 0.45 m{sup 3} CH{sub 4}/kg VS fed and VS removal of 83%. The TPAR shifted to acidification mode at an OLR of 10.0 kg VS/m{sup 3} d and then achieved stable performance at 7.0 kg VS/m{sup 3} d and pH 5.5–6.2, with very high substrate solubilization rate and a methane yield of 0.30 m{sup 3} CH{sub 4}/kg COD fed. The two-phase process was capable of high VS reduction, but material and energy balance showed that the single-phase process was superior in terms of volumetric methane production and energy yield by 33%. The lower energy yield of the two-phase system was due to the loss of energy during hydrolysis in the TPAR and the deficit in methane production in the TPMR attributed to COD loss due to biomass synthesis and adsorption of hard COD onto the flocs. These results including the complicated operational procedure of the two-phase process and the economic factors suggested that the single-phase process could be the preferred system for FVW.« less

Epitaxial layers of 2122 BCSCO superconductor thin films having single crystalline structure

NASA Technical Reports Server (NTRS)

Pandey, Raghvendra K. (Inventor); Raina, Kanwal K. (Inventor); Solayappan, Narayanan (Inventor)

1995-01-01

A substantially single phase, single crystalline, highly epitaxial film of Bi.sub.2 CaSr.sub.2 Cu.sub.2 O.sub.8 superconductor which has a T.sub.c (zero resistance) of 83K is provided on a lattice-matched substrate with no intergrowth. This film is produced by a Liquid Phase Epitaxy method which includes the steps of forming a dilute supercooled molten solution of a single phase superconducting mixture of oxides of Bi, Ca, Sr, and Cu having an atomic ratio of about 2:1:2:2 in a nonreactive flux such as KCl, introducing the substrate, e.g., NdGaO.sub.3, into the molten solution at 850.degree. C., cooling the solution from 850.degree. C. to 830.degree. C. to grow the film and rapidly cooling the substrate to room temperature to maintain the desired single phase, single crystalline film structure.

Crucibleless crystal growth and Radioluminescence study of calcium tungstate single crystal fiber

NASA Astrophysics Data System (ADS)

Silva, M. S.; Jesus, L. M.; Barbosa, L. B.; Ardila, D. R.; Andreeta, J. P.; Silva, R. S.

2014-11-01

In this article, single phase and high optical quality scheelite calcium tungstate single crystal fibers were grown by using the crucibleless laser heated pedestal growth technique. The as-synthesized calcium tungstate powders used for shaping seed and feed rods were investigated by X-ray diffraction technique. As-grown crystals were studied by Raman spectroscopy and Radioluminescence measurements. The results indicate that in both two cases, calcined powder and single crystal fiber, only the expected scheelite CaWO4 phase was observed. It was verified large homogeneity in the crystal composition, without the presence of secondary phases. The Radioluminescence spectra of the as-grown single crystal fibers are in agreement with that present in Literature for bulk single crystals, presented a single emission band centered at 420 nm when irradiated with β-rays.

Development of the self-learning machine for creating models of microprocessor of single-phase earth fault protection devices in networks with isolated neutral voltage above 1000 V

NASA Astrophysics Data System (ADS)

Utegulov, B. B.; Utegulov, A. B.; Meiramova, S.

2018-02-01

The paper proposes the development of a self-learning machine for creating models of microprocessor-based single-phase ground fault protection devices in networks with an isolated neutral voltage higher than 1000 V. Development of a self-learning machine for creating models of microprocessor-based single-phase earth fault protection devices in networks with an isolated neutral voltage higher than 1000 V. allows to effectively implement mathematical models of automatic change of protection settings. Single-phase earth fault protection devices.

Linear phase encoding for holographic data storage with a single phase-only spatial light modulator.

PubMed

Nobukawa, Teruyoshi; Nomura, Takanori

2016-04-01

A linear phase encoding is presented for realizing a compact and simple holographic data storage system with a single spatial light modulator (SLM). This encoding method makes it possible to modulate a complex amplitude distribution with a single phase-only SLM in a holographic storage system. In addition, an undesired light due to the imperfection of an SLM can be removed by spatial frequency filtering with a Nyquist aperture. The linear phase encoding is introduced to coaxial holographic data storage. The generation of a signal beam using linear phase encoding is experimentally verified in an interferometer. In a coaxial holographic data storage system, single data recording, shift selectivity, and shift multiplexed recording are experimentally demonstrated.

Phase-front measurements of an injection-locked AlGaAs laser-diode array

NASA Technical Reports Server (NTRS)

Cornwell, Donald M., Jr.; Rall, Jonathan A. R.; Abshire, James B.

1989-01-01

The phase-front quality of the primary spatial lobe emitted from an injection-locked gain-guided AlGaAs laser-diode array is measured by using an equal-path, phase-shifting Mach-Zehnder interferometer. Root-mean-square phase errors of 0.037 + or - 0.003 wave are measured for the single spatial lobe, which contained 240-mW cw output power in a single longitudinal mode. This phase-front quality corresponds to a Strehl ratio of S = 0.947, which results in a 0.23-dB power loss from the single lobe's ideal diffraction-limited power. These values are comparable with those measured for single-stripe index-guided AlGaAs lasers.

Design of a Modular E-Core Flux Concentrating Axial Flux Machine: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Husain, Tausif; Sozer, Yilmaz; Husain, Iqbal

2015-08-24

In this paper a novel E-Core axial flux machine is proposed. The machine has a double-stator, single-rotor configuration with flux-concentrating ferrite magnets and pole windings across each leg of an E-Core stator. E-Core stators with the proposed flux-concentrating rotor arrangement result in better magnet utilization and higher torque density. The machine also has a modular structure facilitating simpler construction. This paper presents a single-phase and a three-phase version of the E-Core machine. Case studies for a 1.1-kW, 400-rpm machine for both the single-phase and three-phase axial flux machines are presented. The results are verified through 3D finite element analysis. facilitatingmore » simpler construction. This paper presents a single-phase and a three-phase version of the E-Core machine. Case studies for a 1.1-kW, 400-rpm machine for both the single-phase and three-phase axial flux machines are presented. The results are verified through 3D finite element analysis.« less

Optimizing single-nanoparticle two-photon microscopy by in situ adaptive control of femtosecond pulses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Donghai; Deng, Yongkai; Chu, Saisai

2016-07-11

Single-nanoparticle two-photon microscopy shows great application potential in super-resolution cell imaging. Here, we report in situ adaptive optimization of single-nanoparticle two-photon luminescence signals by phase and polarization modulations of broadband laser pulses. For polarization-independent quantum dots, phase-only optimization was carried out to compensate the phase dispersion at the focus of the objective. Enhancement of the two-photon excitation fluorescence intensity under dispersion-compensated femtosecond pulses was achieved. For polarization-dependent single gold nanorod, in situ polarization optimization resulted in further enhancement of two-photon photoluminescence intensity than phase-only optimization. The application of in situ adaptive control of femtosecond pulse provides a way for object-orientedmore » optimization of single-nanoparticle two-photon microscopy for its future applications.« less

Phase formation and UV luminescence of Gd3+ doped perovskite-type YScO3

NASA Astrophysics Data System (ADS)

Shimizu, Yuhei; Ueda, Kazushige

2016-10-01

Synthesis of pure and Gd3+doped perovskite-type YScO3 was attempted by a polymerized complex (PC) method and solid state reaction (SSR) method. Crystalline phases and UV luminescence of samples were examined with varying heating temperatures. The perovskite-type single phase was not simply formed in the SSR method, as reported in some literatures, and two cubic C-type phases of starting oxide materials remained forming slightly mixed solid solutions. UV luminescence of Gd3+ doped samples increased with an increase in heating temperatures and volume of the perovskite-type phase. In contrast, a non-crystalline precursor was crystallized to a single C-type phase at 800 °C in the PC method forming a completely mixed solid solution. Then, the phase of perovskite-type YScO3 formed at 1200 °C and its single phase was obtained at 1400 °C. It was revealed that high homogeneousness of cations was essential to generate the single perovskite-phase of YScO3. Because Gd3+ ions were also dissolved into the single C-type phase in Gd3+ doped samples, intense UV luminescence was observed above 800 °C in both C-type phase and perovskite-type phase.

Fabrication of single phase 2D homologous perovskite microplates by mechanical exfoliation

NASA Astrophysics Data System (ADS)

Li, Junze; Wang, Jun; Zhang, Yingjun; Wang, Haizhen; Lin, Gaoming; Xiong, Xuan; Zhou, Weihang; Luo, Hongmei; Li, Dehui

2018-04-01

The two-dimensional (2D) Ruddlesden-Popper type perovskites have attracted intensive interest for their great environmental stability and various potential optoelectronic applications. Fundamental understanding of the photophysical and electronic properties of the 2D perovskites with pure single phase is essential for improving the performance of the optoelectronic devices and designing devices with new architectures. Investigating the optical and electronic properties of these materials with pure single phase is required to obtain pure single phase 2D perovskites. Here, we report on an alternative approach to fabricate (C4H9NH3)2(CH3NH3) n-1Pb n I3n+1 microplates with pure single n-number perovskite phase for n  >  2 by mechanical exfoliation. Micro-photoluminescence and absorption spectroscopy studies reveal that the as-synthesized 2D perovskite plates for n  >  2 are comprised by dominant n-number phase and small inclusions of hybrid perovskite phases with different n values, which is supported by excitation power dependent photoluminescence. By mechanical exfoliation method, 2D perovskite microplates with the thickness of around 20 nm are obtained, which surprisingly have single n-number perovskite phase for n  =  2-5. In addition, we have demonstrated that the exfoliated 2D perovskite microplates can be integrated with other 2D layered materials such as boron nitride, and are able to be transferred to prefabricated electrodes for photodetections. Our studies not only provide a strategy to prepare 2D perovskites with a single n-number perovskite phase allowing us to extract the basic optical and electronic parameters of pure phase perovskites, but also demonstrate the possibility to integrate the 2D perovskites with other 2D layered materials to extend the device’s functionalities.

Coil planet centrifugation as a means for small particle separation

NASA Technical Reports Server (NTRS)

Herrmann, F. T.

1983-01-01

The coil planet centrifuge uses a centrifugal force field to provide separation of particles based on differences in sedimentation rates by flow through a rotating coiled tube. Three main separations are considered: (1) single phase fresh sheep and human erythrocytes, (2) single phase fixed heep and human erythrocytes, and (3) electrophoretically enhanced single phase fresh sheep and human erythrocytes.

Single-arm phase II trial design under parametric cure models.

PubMed

Wu, Jianrong

2015-01-01

The current practice of designing single-arm phase II survival trials is limited under the exponential model. Trial design under the exponential model may not be appropriate when a portion of patients are cured. There is no literature available for designing single-arm phase II trials under the parametric cure model. In this paper, a test statistic is proposed, and a sample size formula is derived for designing single-arm phase II trials under a class of parametric cure models. Extensive simulations showed that the proposed test and sample size formula perform very well under different scenarios. Copyright © 2015 John Wiley & Sons, Ltd.

Accurate modelling of single-particle cryo-EM images quantifies the benefits expected from using Zernike phase contrast

PubMed Central

Hall, R. J.; Nogales, E.; Glaeser, R. M.

2011-01-01

The use of a Zernike-type phase plate in biological cryo-electron microscopy allows the imaging, without using defocus, of what are predominantly phase objects. It is thought that such phase-plate implementations might result in higher quality images, free from the problems of CTF correction that occur when images must be recorded at extremely high values of defocus. In single-particle cryo-electron microscopy it is hoped that these improvements in image quality will facilitate work on structures that have proved difficult to study, either because of their relatively small size or because the structures are not completely homogeneous. There is still a need, however, to quantify how much improvement can be gained by using a phase plate for single-particle cryo-electron microscopy. We present a method for quantitatively modelling the images recorded with 200 keV electrons, for single particles embedded in vitreous ice. We then investigate what difference the use of a phase-plate device could have on the processing of single-particle data. We confirm that using a phase plate results in single-particle datasets in which smaller molecules can be detected, particles can be more accurately aligned and problems of heterogeneity can be more easily addressed. PMID:21463690

Active thermal control systems for lunar and Martian exploration

NASA Technical Reports Server (NTRS)

Ewert, Michael K.; Petete, Patricia A.; Dzenitis, John

1990-01-01

Several ATCS options including heat pumps, radiator shading devices, and single-phase flow loops were considered. The ATCS chosen for both lunar and Martian habitats consists of a heat pump integral with a nontoxic fluid acquisition and transport loop, and vertically oriented modular reflux-boiler radiators. The heat pump operates only during the lunar day. The lunar and Martian transfer vehicles have an internal single-phase water-acquisition loop and an external two-phase ammonia rejection system with rotating inflatable radiators. The lunar and Martian excursion vehicles incorporate internal single-phase water acquisition, which is connected via heat exchangers to external body-mounted single-phase radiators. A water evaporation system is used for the transfer vehicles during periods of high heating.

Performances of anaerobic co-digestion of fruit & vegetable waste (FVW) and food waste (FW): single-phase vs. two-phase.

PubMed

Shen, Fei; Yuan, Hairong; Pang, Yunzhi; Chen, Shulin; Zhu, Baoning; Zou, Dexun; Liu, Yanping; Ma, Jingwei; Yu, Liang; Li, Xiujin

2013-09-01

The co-digestion of fruit & vegetable waste (FVW) and food waste (FW) was performed at various organic loading ratios (OLRs) in single-phase and two-phase system, respectively. The results showed that the ethanol-type fermentation dominated in both digestion processes when OLR was at low levels (<2.0 g(VS) L(-1) d(-1)). The propionic acid was rapidly accumulated as OLR was increased to higher levels (>2.0 g(VS) L(-1) d(-1)), which could cause unstable anaerobic digestion. Single-phase digestion was better than two-phase digestion in term of 4.1% increase in CH4 production at lower OLRs (<2.0 g(VS) L(-1) d(-1)). However, at higher level of OLR (≥2.0 g(VS) L(-1) d(-1)), two-phase digestion achieved higher CH4 production of 0.351-0.455 L(g VS)(-1) d(-1), which were 7.0-15.8% more than that of single-phase. Additionally, two-phase digestion presented more stable operation, and higher OLR treatment capacity. Furthermore, comparison of these two systems with bioenergy recovery revealed that two-phase system overall presented higher bioenergy yield than single-phase. Copyright © 2013 Elsevier Ltd. All rights reserved.

Reducing Electromagnetic Interference in a Grid Tied Single Phase Power Inverter

DTIC Science & Technology

2016-09-01

ELECTROMAGNETIC INTERFERENCE IN A GRID TIED SINGLE PHASE POWER INVERTER by Jason Hassan Valiani September 2016 Thesis Advisor: Giovanna Oriti...3. REPORT TYPE AND DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE REDUCING ELECTROMAGNETIC INTERFERENCE IN A GRID TIED SINGLE PHASE POWER...explored. The primary goal is to understand the effects each modulation strategy has on the conducted electromagnetic interference (EMI) and then

24 CFR 3280.806 - Receptacle outlets.

Code of Federal Regulations, 2014 CFR

2014-04-01

..., 125-volt, either single or duplex. (b) All 120 volt single phase, 15 and 20 ampere receptacle outlets... Receptacle outlets. (b) All 125-volt, single-phase, 15- and 20-ampere receptacle outlets installed outdoors... 24 Housing and Urban Development 5 2014-04-01 2014-04-01 false Receptacle outlets. 3280.806...

Brief report on the effect of providing single versus assorted brand name condoms to hospital patients: a descriptive study

PubMed Central

Williams, James L; Christensen, Carol J; Cagle, Henry H; Homan, Chriss E

2001-01-01

Objectives This study examined condom acquisition by persons in a hospital setting when single versus assorted brand name condoms were provided. Methods Condom receptacles were placed in exam rooms of two clinics. During Phase 1, a single brand name was provided; for Phase 2, assorted brand names were added. Number of condoms taken was recorded for each phase. Results For one clinic there was nearly a two-fold increase in number of condoms taken (Phase 1 to Phase 2); for the second clinic there was negligible difference in number of condoms taken. Conclusions The provision of assorted brand name condoms, over a single brand name, can serve to increase condom acquisition. Locations of condoms and target population characteristics are related factors. PMID:11446904

Transportation of single cell and microbubbles by phase-shift introduced to standing leaky surface acoustic waves

PubMed Central

Meng, Long; Cai, Feiyan; Zhang, Zidong; Niu, Lili; Jin, Qiaofeng; Yan, Fei; Wu, Junru; Wang, Zhanhui; Zheng, Hairong

2011-01-01

A microfluidic device was developed to precisely transport a single cell or multiple microbubbles by introducing phase-shifts to a standing leaky surface acoustic wave (SLSAW). The device consists of a polydimethyl-siloxane (PDMS) microchannel and two phase-tunable interdigital transducers (IDTs) for the generation of the relative phase for the pair of surface acoustic waves (SAW) propagating along the opposite directions forming a standing wave. When the SAW contacts the fluid medium inside the microchannel, some of SAW energy is coupled to the fluid and the SAW becomes the leaky surface wave. By modulating the relative phase between two IDTs, the positions of pressure nodes of the SLSAW in the microchannel change linearly resulting in the transportation of a single cell or microbubbles. The results also reveal that there is a good linear relationship between the relative phase and the displacement of a single cell or microbubbles. Furthermore, the single cell and the microbubbles can be transported over a predetermined distance continuously until they reach the targeted locations. This technique has its distinct advantages, such as precise position-manipulation, simple to implement, miniature size, and noninvasive character, which may provide an effective method for the position-manipulation of a single cell and microbubbles in many biological and biomedical applications. PMID:22662056

Single-shot three-dimensional reconstruction based on structured light line pattern

NASA Astrophysics Data System (ADS)

Wang, ZhenZhou; Yang, YongMing

2018-07-01

Reconstruction of the object by single-shot is of great importance in many applications, in which the object is moving or its shape is non-rigid and changes irregularly. In this paper, we propose a single-shot structured light 3D imaging technique that calculates the phase map from the distorted line pattern. This technique makes use of the image processing techniques to segment and cluster the projected structured light line pattern from one single captured image. The coordinates of the clustered lines are extracted to form a low-resolution phase matrix which is then transformed to full-resolution phase map by spline interpolation. The 3D shape of the object is computed from the full-resolution phase map and the 2D camera coordinates. Experimental results show that the proposed method was able to reconstruct the three-dimensional shape of the object robustly from one single image.

Multi-phase SPH modelling of violent hydrodynamics on GPUs

NASA Astrophysics Data System (ADS)

Mokos, Athanasios; Rogers, Benedict D.; Stansby, Peter K.; Domínguez, José M.

2015-11-01

This paper presents the acceleration of multi-phase smoothed particle hydrodynamics (SPH) using a graphics processing unit (GPU) enabling large numbers of particles (10-20 million) to be simulated on just a single GPU card. With novel hardware architectures such as a GPU, the optimum approach to implement a multi-phase scheme presents some new challenges. Many more particles must be included in the calculation and there are very different speeds of sound in each phase with the largest speed of sound determining the time step. This requires efficient computation. To take full advantage of the hardware acceleration provided by a single GPU for a multi-phase simulation, four different algorithms are investigated: conditional statements, binary operators, separate particle lists and an intermediate global function. Runtime results show that the optimum approach needs to employ separate cell and neighbour lists for each phase. The profiler shows that this approach leads to a reduction in both memory transactions and arithmetic operations giving significant runtime gains. The four different algorithms are compared to the efficiency of the optimised single-phase GPU code, DualSPHysics, for 2-D and 3-D simulations which indicate that the multi-phase functionality has a significant computational overhead. A comparison with an optimised CPU code shows a speed up of an order of magnitude over an OpenMP simulation with 8 threads and two orders of magnitude over a single thread simulation. A demonstration of the multi-phase SPH GPU code is provided by a 3-D dam break case impacting an obstacle. This shows better agreement with experimental results than an equivalent single-phase code. The multi-phase GPU code enables a convergence study to be undertaken on a single GPU with a large number of particles that otherwise would have required large high performance computing resources.

Linear electro-optic properties of relaxor-based ferroelectric 0.24Pb(In1/2Nb1/2)O3-(0.76 − x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 single crystals

PubMed Central

Wu, Fengmin; Yang, Bin; Sun, Enwei; Liu, Gang; Tian, Hao; Cao, Wenwu

2013-01-01

Linear electro-optic properties of 0.24Pb(In1/2Nb1/2)O3-(0.76 − x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 single crystals, with compositions in the rhombohedral, morphotropic phase boundary (MPB) and tetragonal phases, have been investigated. Very large effective electro-optic coefficient γc (204 pm/V) was observed in a crystal with the MPB composition when it is poled along [001]. The rhombohedral phase (x = 0.27 and 0.30) single crystals poled along [111] direction and tetragonal phase (x = 0.39) single crystal poled along [001] direction are in single domain, and their electro-optic coefficients (γc = 76, 94, and 43 pm/V for the crystals with x = 0.27, 0.30, and 0.39, respectively) were found to be much higher than that of traditional electro-optic single crystal LiNbO3 (γc = 19.9 pm/V). The electro-optic coefficients of the single crystal in the rhombohedral phase have excellent temperature stability in the experimental temperature range of 10–40 °C. The half-wave voltage Vπ was calculated to be much lower (less than 1000 V) than that of LiNbO3 single crystal (2800 V). These superior properties make the ternary relaxor-PT single crystals very promising for electro-optic modulation applications. PMID:23922449

Multiline phase conjugation at 4 microm in germanium.

PubMed

Depatie, D; Haueisen, D

1980-06-01

Phase conjugation by degenerate four-wave mixing in the 4-microm region in germanium has been observed for both single-line and multiline radiation. By using single-line output of a DF laser at 3.8 microm, X3 has been measured to be 4 X 10(-1) esu. Phase conjugation of multiline laser output has been achieved with an efficiency of 0.03%, a level that is consistent with the susceptibility found for single-line phase conjugation and the assumption of independent conjugation of each line of the multiline output.

Single and two-shot quantitative phase imaging using Hilbert-Huang Transform based fringe pattern analysis

NASA Astrophysics Data System (ADS)

Trusiak, Maciej; Micó, Vicente; Patorski, Krzysztof; García-Monreal, Javier; Sluzewski, Lukasz; Ferreira, Carlos

2016-08-01

In this contribution we propose two Hilbert-Huang Transform based algorithms for fast and accurate single-shot and two-shot quantitative phase imaging applicable in both on-axis and off-axis configurations. In the first scheme a single fringe pattern containing information about biological phase-sample under study is adaptively pre-filtered using empirical mode decomposition based approach. Further it is phase demodulated by the Hilbert Spiral Transform aided by the Principal Component Analysis for the local fringe orientation estimation. Orientation calculation enables closed fringes efficient analysis and can be avoided using arbitrary phase-shifted two-shot Gram-Schmidt Orthonormalization scheme aided by Hilbert-Huang Transform pre-filtering. This two-shot approach is a trade-off between single-frame and temporal phase shifting demodulation. Robustness of the proposed techniques is corroborated using experimental digital holographic microscopy studies of polystyrene micro-beads and red blood cells. Both algorithms compare favorably with the temporal phase shifting scheme which is used as a reference method.

Modeling Bi-modality Improves Characterization of Cell Cycle on Gene Expression in Single Cells

PubMed Central

Danaher, Patrick; Finak, Greg; Krouse, Michael; Wang, Alice; Webster, Philippa; Beechem, Joseph; Gottardo, Raphael

2014-01-01

Advances in high-throughput, single cell gene expression are allowing interrogation of cell heterogeneity. However, there is concern that the cell cycle phase of a cell might bias characterizations of gene expression at the single-cell level. We assess the effect of cell cycle phase on gene expression in single cells by measuring 333 genes in 930 cells across three phases and three cell lines. We determine each cell's phase non-invasively without chemical arrest and use it as a covariate in tests of differential expression. We observe bi-modal gene expression, a previously-described phenomenon, wherein the expression of otherwise abundant genes is either strongly positive, or undetectable within individual cells. This bi-modality is likely both biologically and technically driven. Irrespective of its source, we show that it should be modeled to draw accurate inferences from single cell expression experiments. To this end, we propose a semi-continuous modeling framework based on the generalized linear model, and use it to characterize genes with consistent cell cycle effects across three cell lines. Our new computational framework improves the detection of previously characterized cell-cycle genes compared to approaches that do not account for the bi-modality of single-cell data. We use our semi-continuous modelling framework to estimate single cell gene co-expression networks. These networks suggest that in addition to having phase-dependent shifts in expression (when averaged over many cells), some, but not all, canonical cell cycle genes tend to be co-expressed in groups in single cells. We estimate the amount of single cell expression variability attributable to the cell cycle. We find that the cell cycle explains only 5%–17% of expression variability, suggesting that the cell cycle will not tend to be a large nuisance factor in analysis of the single cell transcriptome. PMID:25032992

Dielectric, magnetic, and lattice dynamics properties of Y-type hexaferrite Ba{sub 0.5}Sr{sub 1.5}Zn{sub 2}Fe{sub 12}O{sub 22}: Comparison of ceramics and single crystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kamba, S.; Goian, V.; Savinov, M.

2010-05-15

We prepared multiferroic Y-type hexaferrite Ba{sub 0.5}Sr{sub 1.5}Zn{sub 2}Fe{sub 12}O{sub 22} ceramics and compared their magnetic and dielectric properties with single crystal. Magnetic susceptibility and microwave resonance measurement revealed magnetic phase transition at T{sub C}=312 K, similar as in single crystal. Ferroelectric (FE) phase can be induced by external magnetic field in all investigated samples and the phase diagram in ceramics qualitatively resembles that of the single crystal. The range of magnetic fields, where the FE phase is induced, broadens after annealing of single crystal. Ceramics quenched after sintering exhibit several orders of magnitude lower conductivity than the single crystal.more » Heavily damped magnetic resonance was discovered in terahertz spectra at 10 K and its frequency softens below 5 GHz near T{sub C}. Number and symmetry of observed infrared (IR) and Raman active phonons correspond to paraelectric phase with D{sub 3d}{sup 5} hexagonal structure. No evidence for a structural phase transition was found in the IR and Raman spectra on cooling (in zero magnetic field) or in the room-temperature IR spectra with external static magnetic field up to 0.3 T.« less

Improved battery charger for electric vehicles

NASA Technical Reports Server (NTRS)

Rippel, W. E.

1981-01-01

Polyphase version of single-phase "boost chopper" significantly reduces ripple and electromagnetic interference (EMI). Drive circuit of n-phase boost chopper incorporates n-phase duty-cycle generator; inductor, transistor, and diode compose chopper which can run on single-phase or three-phase alternating current or on direct current. Device retains compactness and power factors approaching unity, while improving efficiency.

Single-shot quantitative phase microscopy with color-multiplexed differential phase contrast (cDPC).

PubMed

Phillips, Zachary F; Chen, Michael; Waller, Laura

2017-01-01

We present a new technique for quantitative phase and amplitude microscopy from a single color image with coded illumination. Our system consists of a commercial brightfield microscope with one hardware modification-an inexpensive 3D printed condenser insert. The method, color-multiplexed Differential Phase Contrast (cDPC), is a single-shot variant of Differential Phase Contrast (DPC), which recovers the phase of a sample from images with asymmetric illumination. We employ partially coherent illumination to achieve resolution corresponding to 2× the objective NA. Quantitative phase can then be used to synthesize DIC and phase contrast images or extract shape and density. We demonstrate amplitude and phase recovery at camera-limited frame rates (50 fps) for various in vitro cell samples and c. elegans in a micro-fluidic channel.

Quantitative phase imaging of biological cells and tissues using singleshot white light interference microscopy and phase subtraction method for extended range of measurement

NASA Astrophysics Data System (ADS)

Mehta, Dalip Singh; Sharma, Anuradha; Dubey, Vishesh; Singh, Veena; Ahmad, Azeem

2016-03-01

We present a single-shot white light interference microscopy for the quantitative phase imaging (QPI) of biological cells and tissues. A common path white light interference microscope is developed and colorful white light interferogram is recorded by three-chip color CCD camera. The recorded white light interferogram is decomposed into the red, green and blue color wavelength component interferograms and processed it to find out the RI for different color wavelengths. The decomposed interferograms are analyzed using local model fitting (LMF)" algorithm developed for reconstructing the phase map from single interferogram. LMF is slightly off-axis interferometric QPI method which is a single-shot method that employs only a single image, so it is fast and accurate. The present method is very useful for dynamic process where path-length changes at millisecond level. From the single interferogram a wavelength-dependent quantitative phase imaging of human red blood cells (RBCs) are reconstructed and refractive index is determined. The LMF algorithm is simple to implement and is efficient in computation. The results are compared with the conventional phase shifting interferometry and Hilbert transform techniques.

Determination of skeleton and sign map for phase obtaining from a single ESPI image

NASA Astrophysics Data System (ADS)

Yang, Xia; Yu, Qifeng; Fu, Sihua

2009-06-01

A robust method of determining the sign map and skeletons for ESPI images is introduced in this paper. ESPI images have high speckle noise which makes it difficult to obtain the fringe information, especially from a single image. To overcome the effects of high speckle noise, local directional computing windows are designed according to the fringe directions. Then by calculating the gradients from the filtered image in directional windows, sign map and good skeletons can be determined robustly. Based on the sign map, single image phase-extracting methods such as quadrature transform can be improved. And based on skeletons, fringe phases can be obtained directly by normalization methods. Experiments show that this new method is robust and effective for extracting phase from a single ESPI fringe image.

Comparison of the quench and fault current limiting characteristics of the flux-coupling type SFCL with single and three-phase transformer

NASA Astrophysics Data System (ADS)

Jung, Byung Ik; Cho, Yong Sun; Park, Hyoung Min; Chung, Dong Chul; Choi, Hyo Sang

2013-01-01

The South Korean power grid has a network structure for the flexible operation of the system. The continuously increasing power demand necessitated the increase of power facilities, which decreased the impedance in the power system. As a result, the size of the fault current in the event of a system fault increased. As this increased fault current size is threatening the breaking capacity of the circuit breaker, the main protective device, a solution to this problem is needed. The superconducting fault current limiter (SFCL) has been designed to address this problem. SFCL supports the stable operation of the circuit breaker through its excellent fault-current-limiting operation [1-5]. In this paper, the quench and fault current limiting characteristics of the flux-coupling-type SFCL with one three-phase transformer were compared with those of the same SFCL type but with three single-phase transformers. In the case of the three-phase transformers, both the superconducting elements of the fault and sound phases were quenched, whereas in the case of the single-phase transformer, only that of the fault phase was quenched. For the fault current limiting rate, both cases showed similar rates for the single line-to-ground fault, but for the three-wire earth fault, the fault current limiting rate of the single-phase transformer was over 90% whereas that of the three-phase transformer was about 60%. It appears that when the three-phase transformer was used, the limiting rate decreased because the fluxes by the fault current of each phase were linked in one core. When the power loads of the superconducting elements were compared by fault type, the initial (half-cycle) load was great when the single-phase transformer was applied, whereas for the three-phase transformer, its power load was slightly lower at the initial stage but became greater after the half fault cycle.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Compere, A.L.; Griffith, W.L.; Googin, J.M.

Microemulsions fuels containing fully and partially coconut, palm, and soy fatty acids; varying amounts of C/sub 1/ to C/sub 4/ alcohols; varying amounts of water; and four fuel bases were evaluated between 0 and 60/sup 0/C for stability as a single phase system. In general, ability to form a stable single phase system rose with increasing alcohol chain length, decreasing water, and increasing dispersed phase content. It was possible to form 0 to 60/sup 0/C stable single phase systems in all four fuels tested using 30 to 50% v/v dispersed phase containing 1-butanol and either palm or soy fatty acids.more » 11 refs., 3 tabs.« less

Theoretical limits on the stability of single-phase kesterite-Cu{sub 2}ZnSnS{sub 4}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sarker, Pranab; Huda, Muhammad N., E-mail: huda@uta.edu; Al-Jassim, Mowafak M.

2015-01-21

The single-phase stability of Cu{sub 2}ZnSnS{sub 4} (CZTS), after an intrinsic defect was incorporated in it, has been examined here for the first time based on ab initio calculations. The stability analysis of such a non-stoichiometric-defect incorporated CZTS shows that the single-phase formation is unlikely at thermodynamic equilibrium conditions. In addition, the effective growth condition of CZTS is determined and quantified for all the elements (Cu-poor, Zn-rich, Sn-poor, and S-rich) to extract maximum photovoltaic efficiency from CZTS. These conditions promote (i) spontaneous formation of Cu vacancy (V{sub Cu}), which might benefit p-type conduction, and (ii) the co-existence of ZnS whilemore » suppressing other harmful defects and secondary phases. Further, the results presented here explain the unavailability of single-phase CZTS to date.« less

Criteria for predicting the formation of single-phase high-entropy alloys

DOE PAGES

Troparevsky, M Claudia; Morris, James R..; Kent, Paul R.; ...

2015-03-15

High entropy alloys constitute a new class of materials whose very existence poses fundamental questions. Originally thought to be stabilized by the large entropy of mixing, these alloys have attracted attention due to their potential applications, yet no model capable of robustly predicting which combinations of elements will form a single-phase currently exists. Here we propose a model that, through the use of high-throughput computation of the enthalpies of formation of binary compounds, is able to confirm all known high-entropy alloys while rejecting similar alloys that are known to form multiple phases. Despite the increasing entropy, our model predicts thatmore » the number of potential single-phase multicomponent alloys decreases with an increasing number of components: out of more than two million possible 7-component alloys considered, fewer than twenty single-phase alloys are likely.« less

Czochralski growth of LaPd2Al2 single crystals

NASA Astrophysics Data System (ADS)

Doležal, P.; Rudajevová, A.; Vlášková, K.; Kriegner, D.; Václavová, K.; Prchal, J.; Javorský, P.

2017-10-01

The present study is focused on the preparation of single crystalline LaPd2Al2 by the Czochralski method. Differential scanning calorimetry (DSC) and energy dispersive X-ray spectroscopy (EDX) analyses reveal that LaPd2Al2 is an incongruently melting phase which causes difficulties for the preparation of single crystalline LaPd2Al2 by the Czochralski method. Therefore several non-stoichiometric polycrystalline samples were studied for its preparation. Finally the successful growth of LaPd2Al2 without foreign phases has been achieved by using a non-stoichiometric precursor with atomic composition 22:39:39 (La:Pd:Al). X-ray powder diffraction, EDX analysis and DSC were used for the characterisation. A single crystalline sample was separated from the ingot prepared by the Czochralski method using the non-stoichiometric precursor. The presented procedure for the preparation of pure single phase LaPd2Al2 could be modified for other incongruently melting phases.

Reconfigurable Transmission Line for a Series-Fed Ku-Band Phased Array Using a Single Feed

NASA Technical Reports Server (NTRS)

Host, Nicholas K.; Chen, Chi-Chih; Volakis, John L.; Miranda. Felix, A.

2013-01-01

The paper presents a novel approach to realize a lowcost phased array using a simple feeding mechanism. Specifically, a single coplanar stripline (CPS) transmission line is used to feed the antenna array elements. By controlling the CPS's dielectric properties using a movable dielectric plunger, scanning is achieved. Due to its simplicity, single feed, and no phase shifters, this approach leads to a dramatic reduction in cost which does not scale for larger arrays.

Single-Photon-Triggered Quantum Phase Transition

NASA Astrophysics Data System (ADS)

Lü, Xin-You; Zheng, Li-Li; Zhu, Gui-Lei; Wu, Ying

2018-06-01

We propose a hybrid quantum model combining cavity QED and optomechanics, which allows the occurrence of an equilibrium superradiant quantum phase transition (QPT) triggered by a single photon. This single-photon-triggered QPT exists in the cases of both ignoring and including the so-called A2 term; i.e., it is immune to the no-go theorem. It originally comes from the photon-dependent quantum criticality featured by the proposed hybrid quantum model. Moreover, a reversed superradiant QPT is induced by the competition between the introduced A2 term and the optomechanical interaction. This work offers an approach to manipulate QPT with a single photon, which should inspire the exploration of single-photon quantum-criticality physics and the engineering of new single-photon quantum devices.

Multiple fuel supply system for an internal combustion engine

DOEpatents

Crothers, William T.

1977-01-01

A multiple fuel supply or an internal combustion engine wherein phase separation of components is deliberately induced. The resulting separation permits the use of a single fuel tank to supply components of either or both phases to the engine. Specifically, phase separation of a gasoline/methanol blend is induced by the addition of a minor amount of water sufficient to guarantee separation into an upper gasoline phase and a lower methanol/water phase. A single fuel tank holds the two-phase liquid with separate fuel pickups and separate level indicators for each phase. Either gasoline or methanol, or both, can be supplied to the engine as required by predetermined parameters. A fuel supply system for a phase-separated multiple fuel supply contained in a single fuel tank is described.

Quantum phase gate based on electromagnetically induced transparency in optical cavities

NASA Astrophysics Data System (ADS)

Borges, Halyne S.; Villas-Bôas, Celso J.

2016-11-01

We theoretically investigate the implementation of a quantum controlled-phase gate in a system constituted by a single atom inside an optical cavity, based on the electromagnetically induced transparency effect. First we show that a probe pulse can experience a π phase shift due to the presence or absence of a classical control field. Considering the interplay of the cavity-EIT effect and the quantum memory process, we demonstrated a controlled-phase gate between two single photons. To this end, first one needs to store a (control) photon in the ground atomic states. In the following, a second (target) photon must impinge on the atom-cavity system. Depending on the atomic state, this second photon will be either transmitted or reflected, acquiring different phase shifts. This protocol can then be easily extended to multiphoton systems, i.e., keeping the control photon stored, it may induce phase shifts in several single photons, thus enabling the generation of multipartite entangled states. We explore the relevant parameter space in the atom-cavity system that allows the implementation of quantum controlled-phase gates using the recent technologies. In particular, we have found a lower bound for the cooperativity of the atom-cavity system which enables the implementation of phase shift on single photons. The induced shift on the phase of a photonic qubit and the controlled-phase gate between single photons, combined with optical devices, enable one to perform universal quantum computation.

The dream of a one-stop-shop: Meta-analysis on myocardial perfusion CT.

PubMed

Pelgrim, Gert Jan; Dorrius, Monique; Xie, Xueqian; den Dekker, Martijn A M; Schoepf, U Joseph; Henzler, Thomas; Oudkerk, Matthijs; Vliegenthart, Rozemarijn

2015-12-01

To determine the diagnostic performance of computed tomography (CT) perfusion techniques for the detection of functionally relevant coronary artery disease (CAD) in comparison to reference standards, including invasive coronary angiography (ICA), single photon emission computed tomography (SPECT), and magnetic resonance imaging (MRI). PubMed, Web of Knowledge and Embase were searched from January 1, 1998 until July 1, 2014. The search yielded 9475 articles. After duplicate removal, 6041 were screened on title and abstract. The resulting 276 articles were independently analyzed in full-text by two reviewers, and included if the inclusion criteria were met. The articles reporting diagnostic parameters including true positive, true negative, false positive and false negative were subsequently evaluated for the meta-analysis. Results were pooled according to CT perfusion technique, namely snapshot techniques: single-phase rest, single-phase stress, single-phase dual-energy stress and combined coronary CT angiography [rest] and single-phase stress, as well the dynamic technique: dynamic stress CT perfusion. Twenty-two articles were included in the meta-analysis (1507 subjects). Pooled per-patient sensitivity and specificity of single-phase rest CT compared to rest SPECT were 89% (95% confidence interval [CI], 82-94%) and 88% (95% CI, 78-94%), respectively. Vessel-based sensitivity and specificity of single-phase stress CT compared to ICA-based >70% stenosis were 82% (95% CI, 64-92%) and 78% (95% CI, 61-89%). Segment-based sensitivity and specificity of single-phase dual-energy stress CT in comparison to stress MRI were 75% (95% CI, 60-85%) and 95% (95% CI, 80-99%). Segment-based sensitivity and specificity of dynamic stress CT perfusion compared to stress SPECT were 77% (95% CI, 67-85) and 89% (95% CI, 78-95%). For combined coronary CT angiography and single-phase stress CT, vessel-based sensitivity and specificity in comparison to ICA-based >50% stenosis were 84% (95% CI, 67-93%) and 93% (95% CI, 89-96%). This meta-analysis shows considerable variation in techniques and reference standards for CT of myocardial blood supply. While CT seems sensitive and specific for evaluation of hemodynamically relevant CAD, studies so far are limited in size. Standardization of myocardial perfusion CT technique is essential. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Analytical results for a conditional phase shift between single-photon pulses in a nonlocal nonlinear medium

NASA Astrophysics Data System (ADS)

Viswanathan, Balakrishnan; Gea-Banacloche, Julio

2017-04-01

We analyze a recent scheme proposed by Xia et al. to induce a conditional phase shift between two single-photon pulses by having them propagate at different speeds through a nonlinear medium with a nonlocal response. We have obtained an analytical solution for the case they considered, which supports their claim that a π phase shift with unit fidelity is possible in principle. We discuss the conditions that have to be met and the challenges and opportunities that this might present to the realization of a single-photon conditional phase gate.

Comparative Analysis of Various Single-tone Frequency Estimation Techniques in High-order Instantaneous Moments Based Phase Estimation Method

NASA Astrophysics Data System (ADS)

Rajshekhar, G.; Gorthi, Sai Siva; Rastogi, Pramod

2010-04-01

For phase estimation in digital holographic interferometry, a high-order instantaneous moments (HIM) based method was recently developed which relies on piecewise polynomial approximation of phase and subsequent evaluation of the polynomial coefficients using the HIM operator. A crucial step in the method is mapping the polynomial coefficient estimation to single-tone frequency determination for which various techniques exist. The paper presents a comparative analysis of the performance of the HIM operator based method in using different single-tone frequency estimation techniques for phase estimation. The analysis is supplemented by simulation results.

2D and 3D X-ray phase retrieval of multi-material objects using a single defocus distance.

PubMed

Beltran, M A; Paganin, D M; Uesugi, K; Kitchen, M J

2010-03-29

A method of tomographic phase retrieval is developed for multi-material objects whose components each has a distinct complex refractive index. The phase-retrieval algorithm, based on the Transport-of-Intensity equation, utilizes propagation-based X-ray phase contrast images acquired at a single defocus distance for each tomographic projection. The method requires a priori knowledge of the complex refractive index for each material present in the sample, together with the total projected thickness of the object at each orientation. The requirement of only a single defocus distance per projection simplifies the experimental setup and imposes no additional dose compared to conventional tomography. The algorithm was implemented using phase contrast data acquired at the SPring-8 Synchrotron facility in Japan. The three-dimensional (3D) complex refractive index distribution of a multi-material test object was quantitatively reconstructed using a single X-ray phase-contrast image per projection. The technique is robust in the presence of noise, compared to conventional absorption based tomography.

Prediction of successful memory encoding based on single-trial rhinal and hippocampal phase information.

PubMed

Höhne, Marlene; Jahanbekam, Amirhossein; Bauckhage, Christian; Axmacher, Nikolai; Fell, Juergen

2016-10-01

Mediotemporal EEG characteristics are closely related to long-term memory formation. It has been reported that rhinal and hippocampal EEG measures reflecting the stability of phases across trials are better suited to distinguish subsequently remembered from forgotten trials than event-related potentials or amplitude-based measures. Theoretical models suggest that the phase of EEG oscillations reflects neural excitability and influences cellular plasticity. However, while previous studies have shown that the stability of phase values across trials is indeed a relevant predictor of subsequent memory performance, the effect of absolute single-trial phase values has been little explored. Here, we reanalyzed intracranial EEG recordings from the mediotemporal lobe of 27 epilepsy patients performing a continuous word recognition paradigm. Two-class classification using a support vector machine was performed to predict subsequently remembered vs. forgotten trials based on individually selected frequencies and time points. We demonstrate that it is possible to successfully predict single-trial memory formation in the majority of patients (23 out of 27) based on only three single-trial phase values given by a rhinal phase, a hippocampal phase, and a rhinal-hippocampal phase difference. Overall classification accuracy across all subjects was 69.2% choosing frequencies from the range between 0.5 and 50Hz and time points from the interval between -0.5s and 2s. For 19 patients, above chance prediction of subsequent memory was possible even when choosing only time points from the prestimulus interval (overall accuracy: 65.2%). Furthermore, prediction accuracies based on single-trial phase surpassed those based on single-trial power. Our results confirm the functional relevance of mediotemporal EEG phase for long-term memory operations and suggest that phase information may be utilized for memory enhancement applications based on deep brain stimulation. Copyright © 2016 Elsevier Inc. All rights reserved.

MDCT of acute pancreatitis: Intraindividual comparison of single-phase versus dual-phase MDCT for initial assessment of acute pancreatitis using different CT scoring systems.

PubMed

Avanesov, Maxim; Weinrich, Julius M; Kraus, Thomas; Derlin, Thorsten; Adam, Gerhard; Yamamura, Jin; Karul, Murat

2016-11-01

The purpose of the retrospective study was to evaluate the additional value of dual-phase multidetector computed tomography (MDCT) protocols over a single-phase protocol on initial MDCT in patients with acute pancreatitis using three CT-based pancreatitis severity scores with regard to radiation dose. In this retrospective, IRB approved study MDCT was performed in 102 consecutive patients (73 males; 55years, IQR48-64) with acute pancreatitis. Inclusion criteria were CT findings of interstitial edematous pancreatitis (IP) or necrotizing pancreatitis (NP) and a contrast-enhanced dual-phase (arterial phase and portal-venous phase) abdominal CT performed at ≥72h after onset of symptoms. The severity of pancreatic and extrapancreatic changes was independently assessed by 2 observers using 3 validated CT-based scoring systems (CTSI, mCTSI, EPIC). All scores were applied to arterial phase and portal venous phase scans and compared to score results of portal venous phase scans, assessed ≥14days after initial evaluation. For effective dose estimation, volume CT dose index (CTDIvol) and dose length product (DLP) were recorded in all examinations. In neither of the CT severity scores a significant difference was observed after application of a dual-phase protocol compared with a single-phase protocol (IP: CTSI: 2.7 vs. 2.5, p=0.25; mCTSI: 4.0 vs. 4.0, p=0.10; EPIC: 2.0 vs. 2.0, p=0.41; NP: CTSI: 8.0 vs. 7.0, p=0.64; mCTSI: 8.0 vs. 8.0, p=0.10; EPIC: 3.0 vs. 3.0, p=0.06). The application of a single-phase CT protocol was associated with a median effective dose reduction of 36% (mean dose reduction 31%) compared to a dual-phase CT scan. An initial dual-phase abdominal CT after ≥72h after onset of symptoms of acute pancreatitis was not superior to a single-phase protocol for evaluation of the severity of pancreatic and extrapancreatic changes. However, the effective radiation dose may be reduced by 36% using a single-phase protocol. Copyright © 2016. Published by Elsevier Ireland Ltd.

Single-shot quantitative phase microscopy with color-multiplexed differential phase contrast (cDPC)

PubMed Central

2017-01-01

We present a new technique for quantitative phase and amplitude microscopy from a single color image with coded illumination. Our system consists of a commercial brightfield microscope with one hardware modification—an inexpensive 3D printed condenser insert. The method, color-multiplexed Differential Phase Contrast (cDPC), is a single-shot variant of Differential Phase Contrast (DPC), which recovers the phase of a sample from images with asymmetric illumination. We employ partially coherent illumination to achieve resolution corresponding to 2× the objective NA. Quantitative phase can then be used to synthesize DIC and phase contrast images or extract shape and density. We demonstrate amplitude and phase recovery at camera-limited frame rates (50 fps) for various in vitro cell samples and c. elegans in a micro-fluidic channel. PMID:28152023

Field-circuit analysis and measurements of a single-phase self-excited induction generator

NASA Astrophysics Data System (ADS)

Makowski, Krzysztof; Leicht, Aleksander

2017-12-01

The paper deals with a single-phase induction machine operating as a stand-alone self-excited single-phase induction generator for generation of electrical energy from renewable energy sources. By changing number of turns and size of wires in the auxiliary stator winding, an improvement of performance characteristics of the generator were obtained as regards no-load and load voltage of the stator windings as well as stator winding currents of the generator. Field-circuit simulation models of the generator were developed using Flux2D software package for the generator with shunt capacitor in the main stator winding. The obtained results have been validated experimentally at the laboratory setup using the single-phase capacitor induction motor of 1.1 kW rated power and 230 V voltage as a base model of the generator.

Study of temperature-dependent Raman spectroscopy and electrical properties in [001]-oriented 0.35Pb(In1/2Nb1/2)O3-0.35Pb(Mg1/3Nb2/3)O3-0.30PbTiO3-Mn single crystals

NASA Astrophysics Data System (ADS)

Liu, Xing; Fang, Bijun; Deng, Ji; Yan, Hong; Deng, Hao; Yue, Qingwen; Ding, Jianning; Zhao, Xiangyong; Luo, Haosu

2016-01-01

In this work, the temperature-dependent Raman spectra and electrical properties of the [001]-oriented 0.5 mol. % Mn-doped 0.35Pb(In1/2Nb1/2)O3-0.35Pb(Mg1/3Nb2/3)O3-0.30PbTiO3-Mn (PIMNT-Mn) single crystals were investigated. All the unpoled and poled PIMNT-Mn single crystals experience a ferroelectric tetragonal phase to paraelectric cubic phase transition (FET-PC) around 183 °C (TC), which exhibits a second-order transition behavior. Whereas, the poled PIMNT-Mn single crystals exhibit another two dielectric anomalies around 130 °C (TRM) and 148 °C (TMT), in which the ferroelectric rhombohedral phase to ferroelectric monoclinic phase (FER-FEM) and the ferroelectric monoclinic phase to ferroelectric tetragonal phase (FEM-FET) transitions take place, respectively. Both the two ferroelectric phase transitions exhibit a first-order transition behavior. The discontinuous change of the phase degree (θ) and frequencies (fr and fa) around TRM suggest the occurrence of the FER-FEM phase transition in the poled PIMNT-Mn single crystals. The narrowing of the 510 cm-1 and 582 cm-1 Raman modes around the TRM, TMT, and TC temperatures shown in the temperature-dependent Raman spectra suggests their increased ordering of the local structure. The intensity ratio of I272 cm-1/I801 cm-1 increases obviously around the phase transition temperatures (TRM, TMT, and TC), indicating the reduction of the long-range order. The anomalous broadening of the 272 cm-1 Raman mode around the TRM, TMT, and TC temperatures indicates the occurrence of the successive ferroelectric phase transitions (FER-FEM, FEM-FET, and FET-PC) with increasing temperature in the poled PIMNT-Mn single crystals.

Quantum phase transitions in spin-1 X X Z chains with rhombic single-ion anisotropy

NASA Astrophysics Data System (ADS)

Ren, Jie; Wang, Yimin; You, Wen-Long

2018-04-01

We explore numerically the inverse participation ratios in the ground state of one-dimensional spin-1 X X Z chains with the rhombic single-ion anisotropy. By employing the techniques of density-matrix renormalization group, effects of the rhombic single-ion anisotropy on various information theoretical measures are investigated, such as the fidelity susceptibility, the quantum coherence, and the entanglement entropy. Their relations with the quantum phase transitions are also analyzed. The phase transitions from the Y -Néel phase to the large-Ex or the Haldane phase can be well characterized by the fidelity susceptibility. The second-order derivative of the ground-state energy indicates all the transitions are of second order. We also find that the quantum coherence, the entanglement entropy, the Schmidt gap, and the inverse participation ratios can be used to detect the critical points of quantum phase transitions. Results drawn from these quantum information observables agree well with each other. Finally we provide a ground-state phase diagram as functions of the exchange anisotropy Δ and the rhombic single-ion anisotropy E .

Magnetic field controlled floating-zone single crystal growth of intermetallic compounds

NASA Astrophysics Data System (ADS)

Hermann, R.; Gerbeth, G.; Priede, J.

2013-03-01

Radio-frequency (RF) floating zone single crystal growth is an important technique for the preparation of single bulk crystals. The advantage of the floating-zone method is the crucible-free growth of single crystals of reactive materials with high melting points. The strong heat diffusion on the surface, as well as the melt convection in the molten zone due to induction heating, often leads to an undesired solid-liquid interface geometry with a concave (towards the solid phase) outer rim. These concave parts aggravate the single crystal growth over the full cross-section. A two-phase stirrer was developed at IFW Dresden in order to avoid the problems connected with these concave parts. It acts as a magnetic field pump and changes the typical double vortex structure to a single roll structure, thus pushing hot melt into the regions where the concave parts may arise. The current in the secondary coil is induced by the primary coil, and the capacitor and the resistance of the secondary circuit are adjusted to get a stable 90 degree phase-shift between the coil currents. Single crystal growth of industrial relevant RuAl and TiAl intermetallic compounds was performed based on the material parameters and using the adjusted two-phase stirrer. Very recently, the magnetic system was applied to the crystal growth of biocompatible TiNb alloys and antiferromagnetic Heusler MnSi compounds.

First Point-Spread Function and X-Ray Phase Contrast Imaging Results with an 88-mm Diameter Single Crystal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lumpkin, A. H.; Garson, A. B.; Anastasio, M. A.

In this study, we report initial demonstrations of the use of single crystals in indirect x-ray imaging with a benchtop implementation of propagation-based (PB) x-ray phase contrast imaging. Based on single Gaussian peak fits to the x-ray images, we observed a four times smaller system point-spread function (PSF) with the 50-μm thick single crystal scintillators than with the reference polycrystalline phosphor/scintillator. Fiber-optic plate depth-of-focus and Al reflective-coating aspects are also elucidated. Guided by the results from the 25-mm diameter crystal samples, we report additionally the first results with a unique 88-mm diameter single crystal bonded to a fiber optic platemore » and coupled to the large format CCD. Both PSF and x-ray phase contrast imaging data are quantified and presented.« less

Highly integrated optical heterodyne phase-locked loop with phase/frequency detection.

PubMed

Lu, Mingzhi; Park, Hyunchul; Bloch, Eli; Sivananthan, Abirami; Bhardwaj, Ashish; Griffith, Zach; Johansson, Leif A; Rodwell, Mark J; Coldren, Larry A

2012-04-23

A highly-integrated optical phase-locked loop with a phase/frequency detector and a single-sideband mixer (SSBM) has been proposed and demonstrated for the first time. A photonic integrated circuit (PIC) has been designed, fabricated and tested, together with an electronic IC (EIC). The PIC integrates a widely-tunable sampled-grating distributed-Bragg-reflector laser, an optical 90 degree hybrid and four high-speed photodetectors on the InGaAsP/InP platform. The EIC adds a single-sideband mixer, and a digital phase/frequency detector, to provide single-sideband heterodyne locking from -9 GHz to 7.5 GHz. The loop bandwith is 400 MHz. © 2012 Optical Society of America

Multifunctional picoliter droplet manipulation platform and its application in single cell analysis.

PubMed

Gu, Shu-Qing; Zhang, Yun-Xia; Zhu, Ying; Du, Wen-Bin; Yao, Bo; Fang, Qun

2011-10-01

We developed an automated and multifunctional microfluidic platform based on DropLab to perform flexible generation and complex manipulations of picoliter-scale droplets. Multiple manipulations including precise droplet generation, sequential reagent merging, and multistep solid-phase extraction for picoliter-scale droplets could be achieved in the present platform. The system precision in generating picoliter-scale droplets was significantly improved by minimizing the thermo-induced fluctuation of flow rate. A novel droplet fusion technique based on the difference of droplet interfacial tensions was developed without the need of special microchannel networks or external devices. It enabled sequential addition of reagents to droplets on demand for multistep reactions. We also developed an effective picoliter-scale droplet splitting technique with magnetic actuation. The difficulty in phase separation of magnetic beads from picoliter-scale droplets due to the high interfacial tension was overcome using ferromagnetic particles to carry the magnetic beads to pass through the phase interface. With this technique, multistep solid-phase extraction was achieved among picoliter-scale droplets. The present platform had the ability to perform complex multistep manipulations to picoliter-scale droplets, which is particularly required for single cell analysis. Its utility and potentials in single cell analysis were preliminarily demonstrated in achieving high-efficiency single-cell encapsulation, enzyme activity assay at the single cell level, and especially, single cell DNA purification based on solid-phase extraction.

Singles correlation energy contributions in solids

NASA Astrophysics Data System (ADS)

Klimeš, Jiří; Kaltak, Merzuk; Maggio, Emanuele; Kresse, Georg

2015-09-01

The random phase approximation to the correlation energy often yields highly accurate results for condensed matter systems. However, ways how to improve its accuracy are being sought and here we explore the relevance of singles contributions for prototypical solid state systems. We set out with a derivation of the random phase approximation using the adiabatic connection and fluctuation dissipation theorem, but contrary to the most commonly used derivation, the density is allowed to vary along the coupling constant integral. This yields results closely paralleling standard perturbation theory. We re-derive the standard singles of Görling-Levy perturbation theory [A. Görling and M. Levy, Phys. Rev. A 50, 196 (1994)], highlight the analogy of our expression to the renormalized singles introduced by Ren and coworkers [Phys. Rev. Lett. 106, 153003 (2011)], and introduce a new approximation for the singles using the density matrix in the random phase approximation. We discuss the physical relevance and importance of singles alongside illustrative examples of simple weakly bonded systems, including rare gas solids (Ne, Ar, Xe), ice, adsorption of water on NaCl, and solid benzene. The effect of singles on covalently and metallically bonded systems is also discussed.

Development of a Single-Crystal Fifth-Generation Nickel Superalloy

NASA Astrophysics Data System (ADS)

Petrushin, N. V.; Elyutin, E. S.; Visik, E. M.; Golynets, S. A.

2017-11-01

The chemical and phase compositions of a rhenium-ruthenium-containing fifth-generation VZhM8 nickel superalloy, which is intended for single-crystal turbine blades of an aviation engine, are calculated using computer simulation. VZhM8 alloy <001>, <011>, and <111> single crystals are fabricated. The microstructure, the γ/γ' misfit, the segregation coefficients of alloying elements, the dissolution temperature of the γ' phase, and the solidus and liquidus temperatures of the VZhM8 alloy single crystals in the as-cast state and after heat treatment are studied. The temperature-time dependences of the static elastic modulus, the short-term mechanical properties, and the long-term strength of the alloy single crystals are determined

Temperature and electric-field induced phase transitions, and full tensor properties of [011] C-poled domain-engineered tetragonal 0 .63 Pb (M g1 /3N b2 /3) -0 .37 PbTi O3 single crystals

NASA Astrophysics Data System (ADS)

Zheng, Limei; Jing, Yujia; Lu, Xiaoyan; Wang, Ruixue; Liu, Gang; Lü, Weiming; Zhang, Rui; Cao, Wenwu

2016-03-01

The phase-transition sequence of 0.67 Pb (M g1 /3N b2 /3)- 0.37 PbTi O3 (PMN-0.37PT) single crystals driven by the electric (E ) field and temperature is comprehensively studied. Based on the strain-E field loop, polarization-E field loop, and the evolution of domain configurations, the E field along the [011] C induced phase transitions have been confirmed to be as follows: tetragonal (T ) → monoclinic (MC)→ single domain orthorhombic (O ) phase. As the E field decreases, the induced O phase cannot be maintained and transformed to the MC phase, then to the coexistence state of MC and T phases. In addition, the complete sets of dielectric, piezoelectric, and elastic constants for the [011] C-poled domain-engineered PMN-0.37PT single crystal were measured at room temperature, which show high longitudinal dielectric, piezoelectric, and electromechanical properties (ɛ33T=10 661 ,d33=1052 pC /N , and k33= 0.766 ). Our results revealed that the MC phase plays an important role in the high electromechanical properties of this domain-engineered single crystal. The temperature dependence of the domain configuration revealed that the volume fraction of the MC phase decreases with temperature accompanied by the reduction of ɛ33T,d31, and k31 due to the substantially smaller intrinsic properties of the T phase.

Can a double stranded DNA be unzipped by pulling a single strand?: phases of adsorbed DNA.

PubMed

Kapri, Rajeev

2009-04-14

We study the unzipping of a double stranded DNA (dsDNA) by applying an external force on a single strand while leaving the other strand free. We find that the dsDNA can be unzipped to two single strands if the external force exceeds a critical value. We obtain the phase diagram, which is found to be different from the phase diagram of unzipping by pulling both the strands in opposite directions. In the presence of an attractive surface near DNA, the phase diagram gets modified drastically and shows richer surprises including a critical end point and a triple point.

Single Aerosol Particle Studies Using Optical Trapping Raman And Cavity Ringdown Spectroscopy

NASA Astrophysics Data System (ADS)

Gong, Z.; Wang, C.; Pan, Y. L.; Videen, G.

2017-12-01

Due to the physical and chemical complexity of aerosol particles and the interdisciplinary nature of aerosol science that involves physics, chemistry, and biology, our knowledge of aerosol particles is rather incomplete; our current understanding of aerosol particles is limited by averaged (over size, composition, shape, and orientation) and/or ensemble (over time, size, and multi-particles) measurements. Physically, single aerosol particles are the fundamental units of any large aerosol ensembles. Chemically, single aerosol particles carry individual chemical components (properties and constituents) in particle ensemble processes. Therefore, the study of single aerosol particles can bridge the gap between aerosol ensembles and bulk/surface properties and provide a hierarchical progression from a simple benchmark single-component system to a mixed-phase multicomponent system. A single aerosol particle can be an effective reactor to study heterogeneous surface chemistry in multiple phases. Latest technological advances provide exciting new opportunities to study single aerosol particles and to further develop single aerosol particle instrumentation. We present updates on our recent studies of single aerosol particles optically trapped in air using the optical-trapping Raman and cavity ringdown spectroscopy.

Simultaneous analysis for water- and fat-soluble vitamins by a novel single chromatography technique unifying supercritical fluid chromatography and liquid chromatography.

PubMed

Taguchi, Kaori; Fukusaki, Eiichiro; Bamba, Takeshi

2014-10-03

Chromatography techniques usually use a single state in the mobile phase, such as liquid, gas, or supercritical fluid. Chromatographers manage one of these techniques for their purpose but are sometimes required to use multiple methods, or even worse, multiple techniques when the target compounds have a wide range of chemical properties. To overcome this challenge, we developed a single method covering a diverse compound range by means of a "unified" chromatography which completely bridges supercritical fluid chromatography and liquid chromatography. In our method, the phase state was continuously changed in the following order; supercritical, subcritical and liquid. Moreover, the gradient of the mobile phase starting at almost 100% CO2 was replaced with 100% methanol at the end completely. As a result, this approach achieved further extension of the polarity range of the mobile phase in a single run, and successfully enabled the simultaneous analysis of fat- and water-soluble vitamins with a wide logP range of -2.11 to 10.12. Furthermore, the 17 vitamins were exceptionally separated in 4min. Our results indicated that the use of dense CO2 and the replacement of CO2 by methanol are practical approaches in unified chromatography covering diverse compounds. Additionally, this is a first report to apply the novel approach to unified chromatography, and can open another door for diverse compound analysis in a single chromatographic technique with single injection, single column and single system. Copyright © 2014. Published by Elsevier B.V.

Direct single-shot phase retrieval from the diffraction pattern of separated objects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leshem, Ben; Xu, Rui; Dallal, Yehonatan

The non-crystallographic phase problem arises in numerous scientific and technological fields. An important application is coherent diffractive imaging. Recent advances in X-ray free-electron lasers allow capturing of the diffraction pattern from a single nanoparticle before it disintegrates, in so-called ‘diffraction before destruction’ experiments. Presently, the phase is reconstructed by iterative algorithms, imposing a non-convex computational challenge, or by Fourier holography, requiring a well-characterized reference field. Here we present a convex scheme for single-shot phase retrieval for two (or more) sufficiently separated objects, demonstrated in two dimensions. In our approach, the objects serve as unknown references to one another, reducing themore » phase problem to a solvable set of linear equations. We establish our method numerically and experimentally in the optical domain and demonstrate a proof-of-principle single-shot coherent diffractive imaging using X-ray free-electron lasers pulses. Lastly, our scheme alleviates several limitations of current methods, offering a new pathway towards direct reconstruction of complex objects.« less

Direct single-shot phase retrieval from the diffraction pattern of separated objects

DOE PAGES

Leshem, Ben; Xu, Rui; Dallal, Yehonatan; ...

2016-02-22

The non-crystallographic phase problem arises in numerous scientific and technological fields. An important application is coherent diffractive imaging. Recent advances in X-ray free-electron lasers allow capturing of the diffraction pattern from a single nanoparticle before it disintegrates, in so-called ‘diffraction before destruction’ experiments. Presently, the phase is reconstructed by iterative algorithms, imposing a non-convex computational challenge, or by Fourier holography, requiring a well-characterized reference field. Here we present a convex scheme for single-shot phase retrieval for two (or more) sufficiently separated objects, demonstrated in two dimensions. In our approach, the objects serve as unknown references to one another, reducing themore » phase problem to a solvable set of linear equations. We establish our method numerically and experimentally in the optical domain and demonstrate a proof-of-principle single-shot coherent diffractive imaging using X-ray free-electron lasers pulses. Lastly, our scheme alleviates several limitations of current methods, offering a new pathway towards direct reconstruction of complex objects.« less

Model predictive direct power control for active power decoupled single-phase quasi- Z -source inverter

DOE PAGES

Liu, Yushan; Ge, Baoming; Abu-Rub, Haitham; ...

2016-06-14

In this study, the active power filter (APF) that consists of a half-bridge leg and an ac capacitor is integrated in the single-phase quasi-Z-source inverter (qZSI) in this paper to avoid the second harmonic power flowing into the dc side. The capacitor of APF buffers the second harmonic power of the load, and the ac capacitor allows highly pulsating ac voltage, so that the capacitances of both dc and ac sides can be small. A model predictive direct power control (DPC) is further proposed to achieve the purpose of this newtopology through predicting the capacitor voltage of APF at eachmore » sampling period and ensuring the APF power to track the second harmonic power of single-phase qZSI. Simulation and experimental results verify the model predictive DPC for the APF-integrated single-phase qZSI.« less

Model predictive direct power control for active power decoupled single-phase quasi- Z -source inverter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Yushan; Ge, Baoming; Abu-Rub, Haitham

In this study, the active power filter (APF) that consists of a half-bridge leg and an ac capacitor is integrated in the single-phase quasi-Z-source inverter (qZSI) in this paper to avoid the second harmonic power flowing into the dc side. The capacitor of APF buffers the second harmonic power of the load, and the ac capacitor allows highly pulsating ac voltage, so that the capacitances of both dc and ac sides can be small. A model predictive direct power control (DPC) is further proposed to achieve the purpose of this newtopology through predicting the capacitor voltage of APF at eachmore » sampling period and ensuring the APF power to track the second harmonic power of single-phase qZSI. Simulation and experimental results verify the model predictive DPC for the APF-integrated single-phase qZSI.« less

Nanocomposites for ultra high density information storage, devices including the same, and methods of making the same

DOEpatents

Goyal, Amit; Shin, Junsoo

2014-04-01

A nanocomposite article that includes a single-crystal or single-crystal-like substrate and heteroepitaxial, phase-separated layer supported by a surface of the substrate and a method of making the same are described. The heteroepitaxial layer can include a continuous, non-magnetic, crystalline, matrix phase, and an ordered, magnetic magnetic phase disposed within the matrix phase. The ordered magnetic phase can include a plurality of self-assembled crystalline nanostructures of a magnetic material. The phase-separated layer and the single crystal substrate can be separated by a buffer layer. An electronic storage device that includes a read-write head and a nanocomposite article with a data storage density of 0.75 Tb/in.sup.2 is also described.

Phase-sensitive flow cytometer

DOEpatents

Steinkamp, John A.

1993-01-01

A phase-sensitive flow cytometer (FCM) provides additional FCM capability to use the fluorescence lifetime of one or more fluorochromes bound to single cells to provide additional information regarding the cells. The resulting fluorescence emission can be resolved into individual fluorescence signals if two fluorochromes are present or can be converted directly to a decay lifetime from a single fluorochrome. The excitation light for the fluorochromes is modulated to produce an amplitude modulated fluorescence pulse as the fluorochrome is excited in the FCM. The modulation signal also forms a reference signal that is phase-shifted a selected amount for subsequent mixing with the output modulated fluorescence intensity signal in phase-sensitive detection circuitry. The output from the phase-sensitive circuitry is then an individual resolved fluorochrome signal or a single fluorochrome decay lifetime, depending on the applied phase shifts.

Phase attraction in sensorimotor synchronization with auditory sequences: effects of single and periodic distractors on synchronization accuracy.

PubMed

Repp, Bruno H

2003-04-01

Four experiments showed that both single and periodic distractor tones affected the timing of finger taps produced in synchrony with an isochronous auditory target sequence. Single distractors had only small effects, but periodic distractors occurring at various fixed or changing phase relationships exerted strong phase attraction. The attraction was asymmetric, being stronger when distractors preceded target tones than when they lagged behind. A large pitch difference between target and distractor tones (20 vs. 3 semitones) did not reduce phase attraction substantially, although in the case of continuously changing phase relationships it did prevent complete capture of the taps by the distractors. The results support the hypothesis that phase attraction is an automatic process that is sensitive primarily to event onsets.

Phase diagram of URu 2–xFe xSi 2 in high magnetic fields

DOE PAGES

Ran, Sheng; Jeon, Inho; Pouse, Naveen; ...

2017-08-28

Here, electrical transport measurements were performed on URu 2-xFe xSi 2 single-crystal specimens in high magnetic fields up to 45 T (DC fields) and 60 T (pulsed fields). We observed a systematic evolution of the critical fields for both the hidden-order (HO) and large-moment antiferromagnetic (LMAFM) phases and established the 3D phase diagram of T–H–x. In the HO phase, H/H 0 scales with T/T 0 and collapses onto a single curve. However, in the LMAFM phase, this single scaling relation is not satisfied. Within a certain range of x values, the HO phase reenters after the LMAFM phase is suppressedmore » by the magnetic field, similar to the behavior observed for URu 2Si 2 within a certain range of pressures.« less

Phase diagram of URu 2–xFe xSi 2 in high magnetic fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ran, Sheng; Jeon, Inho; Pouse, Naveen

Here, electrical transport measurements were performed on URu 2-xFe xSi 2 single-crystal specimens in high magnetic fields up to 45 T (DC fields) and 60 T (pulsed fields). We observed a systematic evolution of the critical fields for both the hidden-order (HO) and large-moment antiferromagnetic (LMAFM) phases and established the 3D phase diagram of T–H–x. In the HO phase, H/H 0 scales with T/T 0 and collapses onto a single curve. However, in the LMAFM phase, this single scaling relation is not satisfied. Within a certain range of x values, the HO phase reenters after the LMAFM phase is suppressedmore » by the magnetic field, similar to the behavior observed for URu 2Si 2 within a certain range of pressures.« less

Directed self-assembly of liquid crystalline blue-phases into ideal single-crystals

NASA Astrophysics Data System (ADS)

Martínez-González, Jose A.; Li, Xiao; Sadati, Monirosadat; Zhou, Ye; Zhang, Rui; Nealey, Paul F.; de Pablo, Juan J.

2017-06-01

Chiral nematic liquid crystals are known to form blue phases--liquid states of matter that exhibit ordered cubic arrangements of topological defects. Blue-phase specimens, however, are generally polycrystalline, consisting of randomly oriented domains that limit their performance in applications. A strategy that relies on nano-patterned substrates is presented here for preparation of stable, macroscopic single-crystal blue-phase materials. Different template designs are conceived to exert control over different planes of the blue-phase lattice orientation with respect to the underlying substrate. Experiments are then used to demonstrate that it is indeed possible to create stable single-crystal blue-phase domains with the desired orientation over large regions. These results provide a potential avenue to fully exploit the electro-optical properties of blue phases, which have been hindered by the existence of grain boundaries.

Growth and characterization of single phase Cu{sub 2}O by thermal oxidation of thin copper films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choudhary, Sumita; Sarma, J. V. N.; Gangopadhyay, Subhashis, E-mail: subhagan@yahoo.com

2016-04-13

We report a simple and efficient technique to form high quality single phase cuprous oxide films on glass substrate using thermal evaporation of thin copper films followed by controlled thermal oxidation in air ambient. Crystallographic analysis and oxide phase determination, as well as grain size distribution have been studied using X-ray diffraction (XRD) method, while scanning electron microscopy (SEM) has been utilized to investigate the surface morphology of the as grown oxide films. The formation of various copper oxide phases is found to be highly sensitive to the oxidation temperature and a crystalline, single phase cuprous oxide film can bemore » achieved for oxidation temperatures between 250°C to 320°C. Cu{sub 2}O film surface appeared in a faceted morphology in SEM imaging and a direct band gap of about 2.1 eV has been observed in UV-visible spectroscopy. X-ray photoelectron spectroscopy (XPS) confirmed a single oxide phase formation. Finally, a growth mechanism of the oxide film has also been discussed.« less

Phase coexistence and domain configuration in Pb(Mg1/3Nb2/3)O3-0.34PbTiO3 single crystal revealed by synchrotron-based X-ray diffractive three-dimensional reciprocal space mapping and piezoresponse force microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Ruixue; Xu, Han; Yang, Bin

The crystalline phases and domain configuration in the morphotropic phase boundary composition Pb(Mg1/3Nb2/3)O3-0.34PbTiO3 (PMN-0.34PT) single crystal have been investigated by synchrotronbased X-ray 3D Reciprocal Space Mapping (3D-RSM) and Piezoresponse Force Microscopy. The coexistence of tetragonal (T) and monoclinic MC phases in this PMN-0.34PT single crystal is confirmed. The affiliation of each diffraction spot in the 3D-RSM was identified with the assistance of qualitative simulation. Most importantly, the twinning structure between different domains in such a mixed phase PMN-PT crystal is firmly clarified, and the spatial distribution of different twin domains is demonstrated. In addition, the lattice parameters of T andmore » MC phases in PMN-0.34PT single crystal as well as the tilting angles of crystal lattices caused by the interfacial lattice mismatch are determined.« less

Study of microbial community and biodegradation efficiency for single- and two-phase anaerobic co-digestion of brown water and food waste.

PubMed

Lim, J W; Chen, C-L; Ho, I J R; Wang, J-Y

2013-11-01

The objective of this work was to study the microbial community and reactor performance for the anaerobic co-digestion of brown water and food waste in single- and two-phase continuously stirred tank reactors (CSTRs). Bacterial and archaeal communities were analyzed after 150 days of reactor operation. As compared to single-phase CSTR, methane production in two-phase CSTR was found to be 23% higher. This was likely due to greater extent of solubilization and acidification observed in the latter. These findings could be attributed to the predominance of Firmicutes and greater bacterial diversity in two-phase CSTR, and the lack of Firmicutes in single-phase CSTR. Methanosaeta was predominant in both CSTRs and this correlated to low levels of acetate in their effluent. Insights gained from this study would enhance the understanding of microorganisms involved in co-digestion of brown water and food waste as well as the complex biochemical interactions promoting digester stability and performance. Copyright © 2013 Elsevier Ltd. All rights reserved.

Development of a 20-MHz wide-bandwidth PMN-PT single crystal phased-array ultrasound transducer.

PubMed

Wong, Chi-Man; Chen, Yan; Luo, Haosu; Dai, Jiyan; Lam, Kwok-Ho; Chan, Helen Lai-Wa

2017-01-01

In this study, a 20-MHz 64-element phased-array ultrasound transducer with a one-wavelength pitch is developed using a PMN-30%PT single crystal and double-matching layer scheme. High piezoelectric (d 33 >1000pC/N) and electromechanical coupling (k 33 >0.8) properties of the single crystal with an optimized fabrication process involving the photolithography technique have been demonstrated to be suitable for wide-bandwidth (⩾70%) and high-sensitivity (insertion loss ⩽30dB) phased-array transducer application. A -6dBbandwidth of 91% and an insertion loss of 29dBfor the 20-MHz 64-element phased-array transducer were achieved. This result shows that the bandwidth is improved comparing with the investigated high-frequency (⩾20MHz) ultrasound transducers using piezoelectric ceramic and single crystal materials. It shows that this phased-array transducer has potential to improve the resolution of biomedical imaging, theoretically. Based on the hypothesis of resolution improvement, this phased-array transducer is capable for small animal (i.e. mouse and zebrafish) studies. Copyright © 2016 Elsevier B.V. All rights reserved.

A new self-regulated self-excited single-phase induction generator using a squirrel cage three-phase induction machine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fukami, Tadashi; Imamura, Michinori; Kaburaki, Yuichi

1995-12-31

A new single-phase capacitor self-excited induction generator with self-regulating feature is presented. The new generator consists of a squirrel cage three-phase induction machine and three capacitors connected in series and parallel with a single phase load. The voltage regulation of this generator is very small due to the effect of the three capacitors. Moreover, since a Y-connected stator winding is employed, the waveform of the output voltage becomes sinusoidal. In this paper the system configuration and the operating principle of the new generator are explained, and the basic characteristics are also investigated by means of a simple analysis and experimentsmore » with a laboratory machine.« less

Synthesis and Characterization of the First Liquid Single Source Precursors for the Deposition of Ternary Chalcopyrite (CuInS2) Thin Film Materials

NASA Technical Reports Server (NTRS)

Banger, Kulbinder K.; Cowen, Jonathan; Hepp, Aloysius

2002-01-01

Molecular engineering of ternary single source precursors based on the [{PBu3}2Cu(SR')2In(SR')2] architecture have afforded the first liquid CIS ternary single source precursors (when R = Et, n-Pr), which are suitable for low temperature deposition (< 350 C). Thermogravimetric analyses (TGA) and modulated-differential scanning calorimetry (DSC) confirm their liquid phase and reduced stability. X-ray diffraction studies, energy dispersive analyzer (EDS), and scanning electron microscopy (SEM) support the formation of the single-phase chalcopyrite CuInS2 at low temperatures.

Optimal visualization of focal nodular hyperplasia: quantitative and qualitative evaluation of single and multiphasic arterial phase acquisition at 1.5 T MR imaging.

PubMed

Rousseau, Caroline; Ronot, Maxime; Vilgrain, Valérie; Zins, Marc

2016-05-01

To evaluate the qualitative and quantitative benefit of multiple arterial phase acquisitions for the depiction of hypervascularity in FNH explored MR imaging using an extracellular contrast agent. Between 2007 and 2014, all patients who underwent MR imaging for the exploration of FNH were included. The protocol included a single or a triple arterial phase ("single" and "triple" group, respectively). Arterial phases were visually divided into four types: (1) angiographic, (2) early, (3) late, and (4) portal. Signal intensity on arterial phase images was visually recorded as intense, moderate, or low for each lesion. Lesion-to-liver contrast (LLC) and relative lesion enhancement (RE) were calculated and compared between the two groups using the Mann-Whitney test. Thirty-five women were included (mean 45-year old, range 20-66), with 50 FNH (mean size 30 mm). Single and triple groups included 20 patients (30 FNH) and 15 patients (20 FNH), respectively. Signal intensity was intense in all lesions in the triple group and in 22/30 (73%) in the single group (p = 0.041). Intense signals were more frequently found in the early arterial phase (p < 0.001). RE was not significantly different (1.78 ± 0.84 vs. 1.98 ± 1.81 p = 0.430, in the single and triple groups, respectively) but LLC was significantly higher in the triple group (0.32 ± 0.10 vs. 0.22 ± 0.10, p = 0.005). LLC was significantly higher in the first two arterial phases in the triple group (p < 0.001). Acquisition of three arterial phases improves the visualization of hypervascularity of FNH, as lesions show high visual signal intensity and contrast. Optimal visualization is obtained in the early arterial phase.

Single domain YBa2Cu3Oy thick films on metallic substrates

NASA Astrophysics Data System (ADS)

Reddy, E. S.; Noudem, J. G.; Goodilin, E. A.; Tarka, M.; Schmitz, G. J.

2003-03-01

The fabrication of single domain YBa2Cu3Oy (123) thick films (10-100 mum) on metallic substrates is reported. The process involves the formation of the 123 phase by a peritectic reaction between an air-brushed dense Y2BaCuO5 (211) layer on a Ag12Pd substrate and infiltrated liquid phases containing barium cuprates and copper oxides. Single domain growth is achieved by seeding the green films with a c-axis oriented NdBa2Cu3Oy crystal prior to processing. The maximum processing temperatures are lowered to 970 °C by modifying the characteristics of the liquid phases meant for infiltration by addition of Ag powder. The fabrication technique, processing conditions for single domain growth and the resulting microstructures are discussed.

Quantum phase transitions driven by rhombic-type single-ion anisotropy in the S =1 Haldane chain

NASA Astrophysics Data System (ADS)

Tzeng, Yu-Chin; Onishi, Hiroaki; Okubo, Tsuyoshi; Kao, Ying-Jer

2017-08-01

The spin-1 Haldane chain is an example of the symmetry-protected-topological (SPT) phase in one dimension. Experimental realization of the spin chain materials usually involves both the uniaxial-type, D (Sz)2 , and the rhombic-type, E [(Sx)2-(Sy)2] , single-ion anisotropies. Here, we provide a precise ground-state phase diagram for a spin-1 Haldane chain with these single-ion anisotropies. Using quantum numbers, we find that the Z2 symmetry breaking phase can be characterized by double degeneracy in the entanglement spectrum. Topological quantum phase transitions take place on particular paths in the phase diagram, from the Haldane phase to the large-Ex, large-Ey, or large-D phases. The topological critical points are determined by the level spectroscopy method with a newly developed parity technique in the density matrix renormalization group [Phys. Rev. B 86, 024403 (2012), 10.1103/PhysRevB.86.024403], and the Haldane-large-D critical point is obtained with an unprecedented precision, (D/J ) c=0.9684713 (1 ) . Close to this critical point, a small rhombic single-ion anisotropy |E |/J ≪1 can destroy the Haldane phase and bring the system into a y -Néel phase. We propose that the compound [Ni (HF2) (3-Clpy ) 4] BF4 is a candidate system to search for the y -Néel phase.

The Single-Phase ProtoDUNE Technical Design Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abi, B.

2017-06-21

ProtoDUNE-SP is the single-phase DUNE Far Detector prototype that is under construction and will be operated at the CERN Neutrino Platform (NP) starting in 2018. ProtoDUNE-SP, a crucial part of the DUNE effort towards the construction of the first DUNE 10-kt fiducial mass far detector module (17 kt total LAr mass), is a significant experiment in its own right. With a total liquid argon (LAr) mass of 0.77 kt, it represents the largest monolithic single-phase LArTPC detector to be built to date. It's technical design is given in this report.

Three-dimensional rearrangement of single atoms using actively controlled optical microtraps.

PubMed

Lee, Woojun; Kim, Hyosub; Ahn, Jaewook

2016-05-02

We propose and demonstrate three-dimensional rearrangements of single atoms. In experiments performed with single ⁸⁷Rb atoms in optical microtraps actively controlled by a spatial light modulator, we demonstrate various dynamic rearrangements of up to N = 9 atoms including rotation, 2D vacancy filling, guiding, compactification, and 3D shuffling. With the capability of a phase-only Fourier mask to generate arbitrary shapes of the holographic microtraps, it was possible to place single atoms at arbitrary geometries of a few μm size and even continuously reconfigure them by conveying each atom. For this purpose, we loaded a series of computer-generated phase masks in the full frame rate of 60 Hz of the spatial light modulator, so the animation of phase mask transformed the holographic microtraps in real time, driving each atom along the assigned trajectory. Possible applications of this method of transformation of single atoms include preparation of scalable quantum platforms for quantum computation, quantum simulation, and quantum many-body physics.

The Faceted Discrete Growth and Phase Differentiation During the Directional Solidification of 20SiMnMo5 Steel

NASA Astrophysics Data System (ADS)

Ma, Xiaoping; Li, Dianzhong

2018-07-01

The microstructures, segregation and cooling curve were investigated in the directional solidification of 20SiMnMo5 steel. The typical characteristic of faceted growth is identified. The microstructures within the single cellular and within the single dendritic arm, together with the contradictive segregation distribution against the cooling curve, verify the discrete crystal growth in multi-scales. Not only the single cellular/dendritic arm but also the single martensite zone within the single cellular/dendritic arm is produced by the discrete growth. In the viewpoint of segregation, the basic domain following continuous growth has not been revealed. Along with the multi-scale faceted discrete growth, the phase differentiation happens for both the solid and liquid. The differentiated liquid phases appear and evolve with different sizes, positions, compositions and durations. The physical mechanism for the faceted discrete growth is qualitatively established based on the nucleation of new faceted steps induced by the composition gradient and temperature gradient.

The Faceted Discrete Growth and Phase Differentiation During the Directional Solidification of 20SiMnMo5 Steel

NASA Astrophysics Data System (ADS)

Ma, Xiaoping; Li, Dianzhong

2018-03-01

The microstructures, segregation and cooling curve were investigated in the directional solidification of 20SiMnMo5 steel. The typical characteristic of faceted growth is identified. The microstructures within the single cellular and within the single dendritic arm, together with the contradictive segregation distribution against the cooling curve, verify the discrete crystal growth in multi-scales. Not only the single cellular/dendritic arm but also the single martensite zone within the single cellular/dendritic arm is produced by the discrete growth. In the viewpoint of segregation, the basic domain following continuous growth has not been revealed. Along with the multi-scale faceted discrete growth, the phase differentiation happens for both the solid and liquid. The differentiated liquid phases appear and evolve with different sizes, positions, compositions and durations. The physical mechanism for the faceted discrete growth is qualitatively established based on the nucleation of new faceted steps induced by the composition gradient and temperature gradient.

Total robotic radical rectal resection with da Vinci Xi system: single docking, single phase technique.

PubMed

Tamhankar, Anup Sunil; Jatal, Sudhir; Saklani, Avanish

2016-12-01

This study aims to assess the advantages of Da Vinci Xi system in rectal cancer surgery. It also assesses the initial oncological outcomes after rectal resection with this system from a tertiary cancer center in India. Robotic rectal surgery has distinct advantages over laparoscopy. Total robotic resection is increasing following the evolution of hybrid technology. The latest Da Vinci Xi system (Intuitive Surgical, Sunnyvale, USA) is enabled with newer features to make total robotic resection possible with single docking and single phase. Thirty-six patients underwent total robotic resection in a single phase and single docking. We used newer port positions in a straight line. Median distance from the anal verge was 4.5 cm. Median robotic docking time and robotic procedure time were 9 and 280 min, respectively. Median blood loss was 100 mL. One patient needed conversion to an open approach due to advanced disease. Circumferential resection margin and longitudinal resection margins were uninvolved in all other patients. Median lymph node yield was 10. Median post-operative stay was 7 days. There were no intra-operative adverse events. The latest Da Vinci Xi system has made total robotic rectal surgery feasible in single docking and single phase. With the new system, four arm total robotic rectal surgery may replace the hybrid technique of laparoscopic and robotic surgery for rectal malignancies. The learning curve for the new system appears to be shorter than anticipated. Early perioperative and oncological outcomes of total robotic rectal surgery with the new system are promising. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

First principles numerical model of avalanche-induced arc discharges in electron-irradiated dielectrics

NASA Technical Reports Server (NTRS)

Beers, B. L.; Pine, V. W.; Hwang, H. C.; Bloomberg, H. W.; Lin, D. L.; Schmidt, M. J.; Strickland, D. J.

1979-01-01

The model consists of four phases: single electron dynamics, single electron avalanche, negative streamer development, and tree formation. Numerical algorithms and computer code implementations are presented for the first three phases. An approach to developing a code description of fourth phase is discussed. Numerical results are presented for a crude material model of Teflon.

Phase demodulation from a single fringe pattern based on a correlation technique.

PubMed

Robin, Eric; Valle, Valéry

2004-08-01

We present a method for determining the demodulated phase from a single fringe pattern. This method, based on a correlation technique, searches in a zone of interest for the degree of similarity between a real fringe pattern and a mathematical model. This method, named modulated phase correlation, is tested with different examples.

Shuttle unified navigation filter, revision 1

NASA Technical Reports Server (NTRS)

Muller, E. S., Jr.

1973-01-01

Equations designed to meet the navigation requirements of the separate shuttle mission phases are presented in a series of reports entitled, Space Shuttle GN and C Equation Document. The development of these equations is based on performance studies carried out for each particular mission phase. Although navigation equations have been documented separately for each mission phase, a single unified navigation filter design is embodied in these separate designs. The purpose of this document is to present the shuttle navigation equations in a form in which they would most likely be coded-as the single unified navigation filter used in each mission phase. This document will then serve as a single general reference for the navigation equations replacing each of the individual mission phase navigation documents (which may still be used as a description of a particular navigation phase).

Ashkin-Teller criticality and weak first-order behavior of the phase transition to a fourfold degenerate state in two-dimensional frustrated Ising antiferromagnets

NASA Astrophysics Data System (ADS)

Liu, R. M.; Zhuo, W. Z.; Chen, J.; Qin, M. H.; Zeng, M.; Lu, X. B.; Gao, X. S.; Liu, J.-M.

2017-07-01

We study the thermal phase transition of the fourfold degenerate phases (the plaquette and single-stripe states) in the two-dimensional frustrated Ising model on the Shastry-Sutherland lattice using Monte Carlo simulations. The critical Ashkin-Teller-like behavior is identified both in the plaquette phase region and the single-stripe phase region. The four-state Potts critical end points differentiating the continuous transitions from the first-order ones are estimated based on finite-size-scaling analyses. Furthermore, a similar behavior of the transition to the fourfold single-stripe phase is also observed in the anisotropic triangular Ising model. Thus, this work clearly demonstrates that the transitions to the fourfold degenerate states of two-dimensional Ising antiferromagnets exhibit similar transition behavior.

Phase-sensitive flow cytometer

DOEpatents

Steinkamp, J.A.

1993-12-14

A phase-sensitive flow cytometer (FCM) provides additional FCM capability to use the fluorescence lifetime of one or more fluorochromes bound to single cells to provide additional information regarding the cells. The resulting fluorescence emission can be resolved into individual fluorescence signals if two fluorochromes are present or can be converted directly to a decay lifetime from a single fluorochrome. The excitation light for the fluorochromes is modulated to produce an amplitude modulated fluorescence pulse as the fluorochrome is excited in the FCM. The modulation signal also forms a reference signal that is phase-shifted a selected amount for subsequent mixing with the output modulated fluorescence intensity signal in phase-sensitive detection circuitry. The output from the phase-sensitive circuitry is then an individual resolved fluorochrome signal or a single fluorochrome decay lifetime, depending on the applied phase shifts. 15 figures.

A possible four-phase coexistence in a single-component system

NASA Astrophysics Data System (ADS)

Akahane, Kenji; Russo, John; Tanaka, Hajime

2016-08-01

For different phases to coexist in equilibrium at constant temperature T and pressure P, the condition of equal chemical potential μ must be satisfied. This condition dictates that, for a single-component system, the maximum number of phases that can coexist is three. Historically this is known as the Gibbs phase rule, and is one of the oldest and venerable rules of thermodynamics. Here we make use of the fact that, by varying model parameters, the Gibbs phase rule can be generalized so that four phases can coexist even in single-component systems. To systematically search for the quadruple point, we use a monoatomic system interacting with a Stillinger-Weber potential with variable tetrahedrality. Our study indicates that the quadruple point provides flexibility in controlling multiple equilibrium phases and may be realized in systems with tunable interactions, which are nowadays feasible in several soft matter systems such as patchy colloids.

A possible four-phase coexistence in a single-component system

PubMed Central

Akahane, Kenji; Russo, John; Tanaka, Hajime

2016-01-01

For different phases to coexist in equilibrium at constant temperature T and pressure P, the condition of equal chemical potential μ must be satisfied. This condition dictates that, for a single-component system, the maximum number of phases that can coexist is three. Historically this is known as the Gibbs phase rule, and is one of the oldest and venerable rules of thermodynamics. Here we make use of the fact that, by varying model parameters, the Gibbs phase rule can be generalized so that four phases can coexist even in single-component systems. To systematically search for the quadruple point, we use a monoatomic system interacting with a Stillinger–Weber potential with variable tetrahedrality. Our study indicates that the quadruple point provides flexibility in controlling multiple equilibrium phases and may be realized in systems with tunable interactions, which are nowadays feasible in several soft matter systems such as patchy colloids. PMID:27558452

Preliminary experiments on phase conjugation for flow visualization. [barium titanate single crystals

NASA Technical Reports Server (NTRS)

Weimer, D.; Howes, W. L.

1984-01-01

Barium titanate single crystals are discussed in the context of: the procedure for polarizing a crystal; a test for phase conjugation; transients in the production of phase conjugation; real time readout by a separate laser of a hologram induced within the crystal, including conjugation response times to on-off switching of each beam; and a demonstration of a Twyman-Green interferometer utilizing phase conjugation.

Liquid hydrogen mass flow through a multiple orifice Joule-Thomson device

NASA Astrophysics Data System (ADS)

Papell, S. Stephen; Nyland, Ted W.; Saiyed, Naseem H.

Liquid hydrogen mass flow rate, pressure drop, and temperature drop data were obtained for a number of multiple orifice Joule-Thomas devices known as visco jets. The present investigation continues a study to develop an equation for predicting two phase flow of cryogens through these devices. The test apparatus design allowed isenthalpic expansion of the cryogen through the visco jets. The data covered a range of inlet and outlet operating conditions. The mass flow rate range single phase or two phase was 0.015 to 0.98 lbm/hr. The manufacturer's equation was found to overpredict the single phase hydrogen data by 10 percent and the two phase data by as much as 27 percent. Two modifications of the equation resulted in a data correlation that predicts both the single and two phase flow across the visco jet. The first modification was of a theoretical nature, and the second strictly empirical. The former reduced the spread in the two phase data. It was a multiplication factor of 1 - X applied to the manufacturer's equation. The parameter X is the flow quality downstream of the visco jet based on isenthalpic expansion across the device. The latter modification was a 10 percent correction term that correlated 90 percent of the single and two phase data to within +/- 10 percent scatter band.

Liquid hydrogen mass flow through a multiple orifice Joule-Thomson device

NASA Technical Reports Server (NTRS)

Papell, S. S.; Nyland, Ted W.; Saiyed, Naseem H.

1992-01-01

Liquid hydrogen mass flow rate, pressure drop, and temperature drop data were obtained for a number of multiple orifice Joule-Thomson devices known as visco jets. The present investigation continues a study to develop an equation for predicting two phase flow of cryogens through these devices. The test apparatus design allowed isenthalpic expansion of the cryogen through the visco jets. The data covered a range of inlet and outlet operating conditions. The mass flow rate range single phase or two phase was 0.015 to 0.98 lbm/hr. The manufacturer's equation was found to overpredict the single phase hydrogen data by 10 percent and the two phase data by as much as 27 percent. Two modifications of the equation resulted in a data correlation that predicts both the single and two phase flow across the visco jet. The first modification was of a theoretical nature, and the second strictly empirical. The former reduced the spread in the two phase data. It was a multiplication factor of 1-X applied to the manufacturer's equation. The parameter X is the flow quality downstream of the visco jet based on isenthalpic expansion across the device. The latter modification was a 10 percent correction term that correlated 90 percent of the single and two phase data to within +/- 10 percent scatter band.

Liquid hydrogen mass flow through a multiple orifice Joule-Thomson device

NASA Technical Reports Server (NTRS)

Papell, S. Stephen; Nyland, Ted W.; Saiyed, Naseem H.

1992-01-01

Liquid hydrogen mass flow rate, pressure drop, and temperature drop data were obtained for a number of multiple orifice Joule-Thomas devices known as visco jets. The present investigation continues a study to develop an equation for predicting two phase flow of cryogens through these devices. The test apparatus design allowed isenthalpic expansion of the cryogen through the visco jets. The data covered a range of inlet and outlet operating conditions. The mass flow rate range single phase or two phase was 0.015 to 0.98 lbm/hr. The manufacturer's equation was found to overpredict the single phase hydrogen data by 10 percent and the two phase data by as much as 27 percent. Two modifications of the equation resulted in a data correlation that predicts both the single and two phase flow across the visco jet. The first modification was of a theoretical nature, and the second strictly empirical. The former reduced the spread in the two phase data. It was a multiplication factor of 1 - X applied to the manufacturer's equation. The parameter X is the flow quality downstream of the visco jet based on isenthalpic expansion across the device. The latter modification was a 10 percent correction term that correlated 90 percent of the single and two phase data to within +/- 10 percent scatter band.

Liquid hydrogen mass flow through a multiple orifice Joule-Thomson device

NASA Astrophysics Data System (ADS)

Papell, S. S.; Nyland, Ted W.; Saiyed, Naseem H.

1992-07-01

Liquid hydrogen mass flow rate, pressure drop, and temperature drop data were obtained for a number of multiple orifice Joule-Thomson devices known as visco jets. The present investigation continues a study to develop an equation for predicting two phase flow of cryogens through these devices. The test apparatus design allowed isenthalpic expansion of the cryogen through the visco jets. The data covered a range of inlet and outlet operating conditions. The mass flow rate range single phase or two phase was 0.015 to 0.98 lbm/hr. The manufacturer's equation was found to overpredict the single phase hydrogen data by 10 percent and the two phase data by as much as 27 percent. Two modifications of the equation resulted in a data correlation that predicts both the single and two phase flow across the visco jet. The first modification was of a theoretical nature, and the second strictly empirical. The former reduced the spread in the two phase data. It was a multiplication factor of 1-X applied to the manufacturer's equation. The parameter X is the flow quality downstream of the visco jet based on isenthalpic expansion across the device. The latter modification was a 10 percent correction term that correlated 90 percent of the single and two phase data to within +/- 10 percent scatter band.

Modelling Assisted Design and Synthesis of Highly Porous Materials for Chemical Adsorbents

DTIC Science & Technology

2010-10-01

two phases of crystal, a monoclinic phase within the solution, and after removal from solution a trigonal phase is obtained. The single crystal...days. Single crystal X-ray data showed there existed a monoclinic phase within the solution that, upon removal from solution, rapidly converted to a... monoclinic to trigonal upon desolvation, as the new peak which has emerged matches the simulated PXRD of the trigonal phase. Also, as the sample is

Heavy ion irradiations on synthetic hollandite-type materials: Ba{sub 1.0}Cs{sub 0.3}A{sub 2.3}Ti{sub 5.7}O{sub 16} (A=Cr, Fe, Al)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tang, Ming, E-mail: mtang@lanl.gov; Tumurugoti, Priyatham; Clark, Braeden

2016-07-15

The hollandite supergroup of minerals has received considerable attention as a nuclear waste form for immobilization of Cs. The radiation stability of synthetic hollandite-type compounds described generally as Ba{sub 1.0}Cs{sub 0.3}A{sub 2.3}Ti{sub 5.7}O{sub 16} (A=Cr, Fe, Al) were evaluated by heavy ion (Kr) irradiations on polycrystalline single phase materials and multiphase materials incorporating the hollandite phases. Ion irradiation damage effects on these samples were examined using grazing incidence X-ray diffraction (GIXRD) and transmission electron microscopy (TEM). Single phase compounds possess tetragonal structure with space group I4/m. GIXRD and TEM observations revealed that 600 keV Kr irradiation-induced amorphization on single phasemore » hollandites compounds occurred at a fluence between 2.5×10{sup 14} Kr/cm{sup 2} and 5×10{sup 14} Kr/cm{sup 2}. The critical amorphization fluence of single phase hollandite compounds obtained by in situ 1 MeV Kr ion irradiation was around 3.25×10{sup 14} Kr/cm{sup 2}. The hollandite phase exhibited similar amorphization susceptibility under Kr ion irradiation when incorporated into a multiphase system. - Graphical abstract: 600 keV Kr irradiation-induced amorphization on single phase hollandites compounds occurred at a fluence between 2.5×10{sup 14} Kr/cm{sup 2} and 5×10{sup 14} Kr/cm{sup 2}. The hollandite phase exhibited similar amorphization susceptibility under Kr ion irradiation when incorporated into a multiphase system. This is also the first time that the critical amorphization fluence of single phase hollandite compounds were determined at a fluence of around 3.25×10{sup 14} Kr/cm{sup 2} by in situ 1 MeV Kr ion irradiation. Display Omitted.« less

Tutorial on Quantification of Differences between Single- and Two-Component Two-Phase Flow and Heat Transfer

NASA Astrophysics Data System (ADS)

Delil, A. A. M.

2003-01-01

Single-component two-phase systems are envisaged for aerospace thermal control applications: Mechanically Pumped Loops, Vapour Pressure Driven Loops, Capillary Pumped Loops and Loop Heat Pipes. Thermal control applications are foreseen in different gravity environments: Micro-g, reduced-g for Mars or Moon bases, 1-g during terrestrial testing, and hyper-g in rotating spacecraft, during combat aircraft manoeuvres and in systems for outer planets. In the evaporator, adiabatic line and condenser sections of such single-component two-phase systems, the fluid is a mixture of the working liquid (for example ammonia, carbon dioxide, ethanol, or other refrigerants, etc.) and its saturated vapour. Results of two-phase two-component flow and heat transfer research (pertaining to liquid-gas mixtures, e.g. water/air, or argon or helium) are often applied to support research on flow and heat transfer in two-phase single-component systems. The first part of the tutorial updates the contents of two earlier tutorials, discussing various aerospace-related two-phase flow and heat transfer research. It deals with the different pressure gradient constituents of the total pressure gradient, with flow regime mapping (including evaporating and condensing flow trajectories in the flow pattern maps), with adiabatic flow and flashing, and with thermal-gravitational scaling issues. The remaining part of the tutorial qualitatively and quantitatively determines the differences between single- and two-component systems: Two systems that physically look similar and close, but in essence are fully different. It was already elucidated earlier that, though there is a certain degree of commonality, the differences will be anything but negligible, in many cases. These differences (quantified by some examples) illustrates how careful one shall be in interpreting data resulting from two-phase two-component simulations or experiments, for the development of single-component two-phase thermal control systems for various gravity environments.

Optimization of the crystal growth of the superconductor CaKFe4As4 from solution in the FeAs -CaFe2As2-KFe2As2 system

NASA Astrophysics Data System (ADS)

Meier, W. R.; Kong, T.; Bud'ko, S. L.; Canfield, P. C.

2017-06-01

Measurements of the anisotropic properties of single crystals play a crucial role in probing the physics of new materials. Determining a growth protocol that yields suitable high-quality single crystals can be particularly challenging for multicomponent compounds. Here we present a case study of how we refined a procedure to grow single crystals of CaKFe4As4 from a high temperature, quaternary liquid solution rich in iron and arsenic ("FeAs self-flux"). Temperature dependent resistance and magnetization measurements are emphasized, in addition to the x-ray diffraction, to detect intergrown CaKFe4As4 , CaFe2As2 , and KFe2As2 within what appear to be single crystals. Guided by the rules of phase equilibria and these data, we adjusted growth parameters to suppress formation of the impurity phases. The resulting optimized procedure yielded phase-pure single crystals of CaKFe4As4 . This optimization process offers insight into the growth of quaternary compounds and a glimpse of the four-component phase diagram in the pseudoternary FeAs -CaFe2As2-KFe2As2 system.

Development of a single-phase thermosiphon for cold collection and storage of radiative cooling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Dongliang; Martini, Christine Elizabeth; Jiang, Siyu

A single-phase thermosiphon is developed for cold collection and storage of radiative cooling. Compared to the conventional nocturnal radiative cooling systems that use an electric pump to drive the heat transfer fluid, the proposed single-phase thermosiphon uses the buoyancy force to drive heat transfer fluid. This solution does not require electricity, therefore improving the net gain of the radiative cooling system. A single-phase thermosiphon was built, which consists of a flat panel, a cold collection tank, a water return tube, and a water distribution tank. Considering that outdoor radiative cooling flux is constantly changing (i.e. uncontrollable), an indoor testing facilitymore » was developed to provide a controllable cooling flux (comparable to a radiative cooling flux of 100 W/m2) for the evaluation of thermosiphon performance. The testing apparatus is a chilled aluminum flat plate that has a controlled air gap separation relative to the flat panel surface of the thermosiphon to emulate radiative cooling. With an average of 105 W/m2 cooling flux, the 18 liters of water in the thermosiphon was cooled to an average temperature of 12.5 degrees C from an initial temperature of 22.2 degrees C in 2 h, with a cold collection efficiency of 96.8%. The results obtained have demonstrated the feasibility of using a single-phase thermosiphon for cold collection and storage of radiative cooling. Additionally, the effects of the thermosiphon operation conditions, such as tilt angle of the flat panel, initial water temperature, and cooling energy flux, on the performance have been experimentally investigated. Modular design of the single-phase thermosiphon gives flexibility for its scalability. A radiative cooling system with multiple thermosiphon modules is expected to play an important role in cooling buildings and power plant condensers.« less

Thin Film CuInS2 Prepared by Spray Pyrolysis with Single-Source Precursors

NASA Technical Reports Server (NTRS)

Jin, Michael H.; Banger, Kulinder K.; Harris, Jerry D.; Cowen, Jonathan E.; Hepp, Aloysius F.; Lyons, Valerie (Technical Monitor)

2002-01-01

Both horizontal hot-wall and vertical cold-wall atmospheric chemical spray pyrolysis processes deposited near single-phase stoichiometric CuInS2 thin films. Single-source precursors developed for ternary chalcopyrite materials were used for this study, and a new liquid phase single-source precursor was tested with a vertical cold-wall reactor. The depositions were carried out under an argon atmosphere, and the substrate temperature was kept at 400 C. Columnar grain structure was obtained with vapor deposition, and the granular structure was obtained with (liquid) droplet deposition. Conductive films were deposited with planar electrical resistivities ranging from 1 to 30 Omega x cm.

Quantitative experimental determination of the solid solution hardening potential of rhenium, tungsten and molybdenum in single-crystal nickel-based superalloys

DOE PAGES

Fleischmann, Ernst; Miller, Michael K.; Affeldt, Ernst; ...

2015-01-31

Here, the solid-solution hardening potential of the refractory elements rhenium, tungsten and molybdenum in the matrix of single-crystal nickel-based superalloys was experimentally quantified. Single-phase alloys with the composition of the nickel solid-solution matrix of superalloys were cast as single crystals, and tested in creep at 980 °C and 30–75 MPa. The use of single-phase single-crystalline material ensures very clean data because no grain boundary or particle strengthening effects interfere with the solid-solution hardening. This makes it possible to quantify the amount of rhenium, tungsten and molybdenum necessary to reduce the creep rate by a factor of 10. Rhenium is moremore » than two times more effective for matrix strengthening than either tungsten or molybdenum. The existence of rhenium clusters as a possible reason for the strong strengthening effect is excluded as a result of atom probe tomography measurements. If the partitioning coefficient of rhenium, tungsten and molybdenum between the γ matrix and the γ' precipitates is taken into account, the effectiveness of the alloying elements in two-phase superalloys can be calculated and the rhenium effect can be explained.« less

A Comparison between Growth Morphology of "Eutectic" Cells/Dendrites and Single-Phase Cells/Dendrites

NASA Technical Reports Server (NTRS)

Tewari, S. N.; Raj, S. V.; Locci, I. E.

2003-01-01

Directionally solidified (DS) intermetallic and ceramic-based eutectic alloys with an in-situ composite microstructure containing finely distributed, long aspect ratio, fiber, or plate reinforcements are being seriously examined for several advanced aero-propulsion applications. In designing these alloys, additional solutes need to be added to the base eutectic composition in order to improve heir high-temperature strength, and provide for adequate toughness and resistance to environmental degradation. Solute addition, however, promotes instability at the planar liquid-solid interface resulting in the formation of two-phase eutectic "colonies." Because morphology of eutectic colonies is very similar to the single-phase cells and dendrites, the stability analysis of Mullins and Sekerka has been extended to describe their formation. Onset of their formation shows a good agreement with this approach; however, unlike the single-phase cells and dendrites, there is limited examination of their growth speed dependence of spacing, morphology, and spatial distribution. The purpose of this study is to compare the growth speed dependence of the morphology, spacing, and spatial distribution of eutectic cells and dendrites with that for the single-phase cells and dendrites.

Reentrant behaviors in the phase diagram of spin-1 planar ferromagnet with single-ion anisotropy

NASA Astrophysics Data System (ADS)

Rabuffo, I.; De Cesare, L.; Caramico D'Auria, A.; Mercaldo, M. T.

2018-05-01

We used the two-time Green function framework to investigate the role played by the easy-axis single-ion anisotropy on the phase diagram of (d > 2)-dimensional spin-1planar ferromagnets, which exhibit a magnetic field induced quantum phase transition. We tackled the problem using two different kind of approximations: the Anderson-Callen decoupling scheme and the Devlin approach. In the latter scheme, the exchange anisotropy terms in the equations of motion are treated at the Tyablikov decoupling level while the crystal field anisotropy contribution is handled exactly. The emerging key result is a reentrant structure of the phase diagram close to the quantum critical point, for certain values of the single-ion anisotropy parameter. We compare the results obtained within the two approximation schemes. In particular, we recover the same qualitative behavior. We show the phase diagram, close to the field-induced quantum critical point and the behavior of the susceptibility for different values of the single-ion anisotropy parameter, enhancing the differences between the two different scenarios (i.e. with and without reentrant behavior).

Coherent single-atom superradiance

NASA Astrophysics Data System (ADS)

Kim, Junki; Yang, Daeho; Oh, Seung-hoon; An, Kyungwon

2018-02-01

Superradiance is a quantum phenomenon emerging in macroscopic systems whereby correlated single atoms cooperatively emit photons. Demonstration of controlled collective atom-field interactions has resulted from the ability to directly imprint correlations with an atomic ensemble. Here we report cavity-mediated coherent single-atom superradiance: Single atoms with predefined correlation traverse a high–quality factor cavity one by one, emitting photons cooperatively with the N atoms that have already gone through the cavity (N represents the number of atoms). Enhanced collective photoemission of N-squared dependence was observed even when the intracavity atom number was less than unity. The correlation among single atoms was achieved by nanometer-precision position control and phase-aligned state manipulation of atoms by using a nanohole-array aperture. Our results demonstrate a platform for phase-controlled atom-field interactions.

A single-phase elastic hyperbolic metamaterial with anisotropic mass density.

PubMed

Zhu, R; Chen, Y Y; Wang, Y S; Hu, G K; Huang, G L

2016-06-01

Wave propagation can be manipulated at a deep subwavelength scale through the locally resonant metamaterial that possesses unusual effective material properties. Hyperlens due to metamaterial's anomalous anisotropy can lead to superior-resolution imaging. In this paper, a single-phase elastic metamaterial with strongly anisotropic effective mass density has been designed. The proposed metamaterial utilizes the independently adjustable locally resonant motions of the subwavelength-scale microstructures along the two principal directions. High anisotropy in the effective mass densities obtained by the numerical-based effective medium theory can be found and even have opposite signs. For practical applications, shunted piezoelectric elements are introduced into the microstructure to tailor the effective mass density in a broad frequency range. Finally, to validate the design, an elastic hyperlens made of the single-phase hyperbolic metamaterial is proposed with subwavelength longitudinal wave imaging illustrated numerically. The proposed single-phase hyperbolic metamaterial has many promising applications for high resolution damage imaging in nondestructive evaluation and structural health monitoring.

FIELD IMPLEMENTATION OF A WINSOR TYPE I SURFACTANT/ALCOHOL MIXTURE FOR IN SITU SOLUBILIZATION OF A COMPLEX LNAPL AS A SINGLE-PHASE MICROEMULSION

EPA Science Inventory

A Winsor Type I surfactant/alcohol mixture was used as an in situ flushing agent to solubilize a muticomponent nonaqueous phase liquid (NAPL) as a single-phase microemulsion (SPME) in a hydraulically isolated test cell at Hill Air Force Base (AFB), Utah. The surfactant (polyoxye...

Phase coexistence and domain configuration in Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-0.34PbTiO{sub 3} single crystal revealed by synchrotron-based X-ray diffractive three-dimensional reciprocal space mapping and piezoresponse force microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Ruixue; Yang, Bin, E-mail: binyang@hit.edu.cn; Sun, Enwei

The crystalline phases and domain configuration in the morphotropic phase boundary composition Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-0.34PbTiO{sub 3} (PMN-0.34PT) single crystal have been investigated by synchrotron-based X-ray 3D Reciprocal Space Mapping (3D-RSM) and Piezoresponse Force Microscopy. The coexistence of tetragonal (T) and monoclinic M{sub C} phases in this PMN-0.34PT single crystal is confirmed. The affiliation of each diffraction spot in the 3D-RSM was identified with the assistance of qualitative simulation. Most importantly, the twinning structure between different domains in such a mixed phase PMN-PT crystal is firmly clarified, and the spatial distribution of different twin domains is demonstrated. In addition, themore » lattice parameters of T and M{sub C} phases in PMN-0.34PT single crystal as well as the tilting angles of crystal lattices caused by the interfacial lattice mismatch are determined.« less

Heavy ion irradiations on synthetic hollandite-type materials: Ba1.0Cs0.3A2.3Ti5.7O16 (A=Cr, Fe, Al)

NASA Astrophysics Data System (ADS)

Tang, Ming; Tumurugoti, Priyatham; Clark, Braeden; Sundaram, S. K.; Amoroso, Jake; Marra, James; Sun, Cheng; Lu, Ping; Wang, Yongqiang; Jiang, Ying.-Bing.

2016-07-01

The hollandite supergroup of minerals has received considerable attention as a nuclear waste form for immobilization of Cs. The radiation stability of synthetic hollandite-type compounds described generally as Ba1.0Cs0.3A2.3Ti5.7O16 (A=Cr, Fe, Al) were evaluated by heavy ion (Kr) irradiations on polycrystalline single phase materials and multiphase materials incorporating the hollandite phases. Ion irradiation damage effects on these samples were examined using grazing incidence X-ray diffraction (GIXRD) and transmission electron microscopy (TEM). Single phase compounds possess tetragonal structure with space group I4/m. GIXRD and TEM observations revealed that 600 keV Kr irradiation-induced amorphization on single phase hollandites compounds occurred at a fluence between 2.5×1014 Kr/cm2 and 5×1014 Kr/cm2. The critical amorphization fluence of single phase hollandite compounds obtained by in situ 1 MeV Kr ion irradiation was around 3.25×1014 Kr/cm2. The hollandite phase exhibited similar amorphization susceptibility under Kr ion irradiation when incorporated into a multiphase system.

Phase-encoded single-voxel magnetic resonance spectroscopy for suppressing outer volume signals at 7 Tesla.

PubMed

Li, Ningzhi; An, Li; Johnson, Christopher; Shen, Jun

2017-01-01

Due to imperfect slice profiles, unwanted signals from outside the selected voxel may significantly contaminate metabolite signals acquired using in vivo magnetic resonance spectroscopy (MRS). The use of outer volume suppression may exceed the SAR threshold, especially at high field. We propose using phase-encoding gradients after radiofrequency (RF) excitation to spatially encode unwanted signals originating from outside of the selected single voxel. Phase-encoding gradients were added to a standard single voxel point-resolved spectroscopy (PRESS) sequence which selects a 2 × 2 × 2 cm 3 voxel. Subsequent spatial Fourier transform was used to encode outer volume signals. Phantom and in vivo experiments were performed using both phase-encoded PRESS and standard PRESS at 7 Tesla. Quantification was performed using fitting software developed in-house. Both phantom and in vivo studies showed that spectra from the phase-encoded PRESS sequence were relatively immune from contamination by oil signals and have more accurate quantification results than spectra from standard PRESS spectra of the same voxel. The proposed phase-encoded single-voxel PRESS method can significantly suppress outer volume signals that may appear in the spectra of standard PRESS without increasing RF power deposition.

Design of a Modular E-Core Flux Concentrating Axial Flux Machine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Husain, Tausif; Sozer, Yilmaz; Husain, Iqbal

2015-09-02

In this paper a novel E-Core axial flux machine is proposed. The machine has a double stator-single rotor configuration with flux concentrating ferrite magnets, and pole windings across each leg of an E-Core stator. E-Core stators with the proposed flux-concentrating rotor arrangement result in better magnet utilization and higher torque density. The machine also has a modular structure facilitating simpler construction. This paper presents a single phase and a three-phase version of the E-Core machine. Case study for a 1.1 kW, 400 rpm machine for both the single phase and three-phase axial flux machine is presented. The results are verifiedmore » through 3D finite element analysis.« less

Phase reconstruction using compressive two-step parallel phase-shifting digital holography

NASA Astrophysics Data System (ADS)

Ramachandran, Prakash; Alex, Zachariah C.; Nelleri, Anith

2018-04-01

The linear relationship between the sample complex object wave and its approximated complex Fresnel field obtained using single shot parallel phase-shifting digital holograms (PPSDH) is used in compressive sensing framework and an accurate phase reconstruction is demonstrated. It is shown that the accuracy of phase reconstruction of this method is better than that of compressive sensing adapted single exposure inline holography (SEOL) method. It is derived that the measurement model of PPSDH method retains both the real and imaginary parts of the Fresnel field but with an approximation noise and the measurement model of SEOL retains only the real part exactly equal to the real part of the complex Fresnel field and its imaginary part is completely not available. Numerical simulation is performed for CS adapted PPSDH and CS adapted SEOL and it is demonstrated that the phase reconstruction is accurate for CS adapted PPSDH and can be used for single shot digital holographic reconstruction.

Directed Self-Assembly of Liquid Crystalline Blue-Phases into Ideal Single-Crystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martinez-Gonzalez, Jose A.; Li, Xiao; Sadati, Monirosadat

Chiral nematic liquid crystals are known to form blue phases—liquid states of matter that exhibit ordered cubic arrangements of topological defects. Blue-phase specimens, however, are generally polycrystalline, consisting of randomly oriented domains that limit their performance in applications. A strategy that relies on nano-patterned substrates is presented here for preparation of stable, macroscopic single-crystal blue-phase materials. Different template designs are conceived to exert control over different planes of the blue-phase lattice orientation with respect to the underlying substrate. Experiments are then used to demonstrate that it is indeed possible to create stable single-crystal blue-phase domains with the desired orientation overmore » large regions. Lastly, these results provide a potential avenue to fully exploit the electro-optical properties of blue phases, which have been hindered by the existence of grain boundaries.« less

Directed Self-Assembly of Liquid Crystalline Blue-Phases into Ideal Single-Crystals

DOE PAGES

Martinez-Gonzalez, Jose A.; Li, Xiao; Sadati, Monirosadat; ...

2017-06-16

Chiral nematic liquid crystals are known to form blue phases—liquid states of matter that exhibit ordered cubic arrangements of topological defects. Blue-phase specimens, however, are generally polycrystalline, consisting of randomly oriented domains that limit their performance in applications. A strategy that relies on nano-patterned substrates is presented here for preparation of stable, macroscopic single-crystal blue-phase materials. Different template designs are conceived to exert control over different planes of the blue-phase lattice orientation with respect to the underlying substrate. Experiments are then used to demonstrate that it is indeed possible to create stable single-crystal blue-phase domains with the desired orientation overmore » large regions. Lastly, these results provide a potential avenue to fully exploit the electro-optical properties of blue phases, which have been hindered by the existence of grain boundaries.« less

External and Intraparticle Diffusion of Coumarin 102 with Surfactant in the ODS-silica Gel/water System by Single Microparticle Injection and Confocal Fluorescence Microspectroscopy.

PubMed

Nakatani, Kiyoharu; Matsuta, Emi

2015-01-01

The release mechanism of coumarin 102 from a single ODS-silica gel microparticle into the water phase in the presence of Triton X-100 was investigated by confocal fluorescence microspectroscopy combined with the single microparticle injection technique. The release rate significantly depended on the Triton X-100 concentration in the water phase and was not limited by diffusion in the pores of the microparticle. The release rate constant was inversely proportional to the microparticle radius squared, indicating that the rate-determining step is the external diffusion between the microparticle and the water phase.

The application of single particle hydrodynamics in continuum models of multiphase flow

NASA Technical Reports Server (NTRS)

Decker, Rand

1988-01-01

A review of the application of single particle hydrodynamics in models for the exchange of interphase momentum in continuum models of multiphase flow is presented. Considered are the equations of motion for a laminar, mechanical two phase flow. Inherent to this theory is a model for the interphase exchange of momentum due to drag between the dispersed particulate and continuous fluid phases. In addition, applications of two phase flow theory to de-mixing flows require the modeling of interphase momentum exchange due to lift forces. The applications of single particle analysis in deriving models for drag and lift are examined.

Mechanism of generation of large (Ti,Nb,V)(C,N)-type precipitates in H13 + Nb tool steel

NASA Astrophysics Data System (ADS)

Xie, You; Cheng, Guo-guang; Chen, Lie; Zhang, Yan-dong; Yan, Qing-zhong

2016-11-01

The characteristics and generation mechanism of (Ti,Nb,V)(C,N) precipitates larger than 2 μm in Nb-containing H13 bar steel were studied. The results show that two types of (Ti,Nb,V)(C,N) phases exist—a Ti-V-rich one and an Nb-rich one—in the form of single or complex precipitates. The sizes of the single Ti-V-rich (Ti,Nb,V)(C,N) precipitates are mostly within 5 to 10 μm, whereas the sizes of the single Nb-rich precipitates are mostly 2-5 μm. The complex precipitates are larger and contain an inner Ti-V-rich layer and an outer Nb-rich layer. The compositional distribution of (Ti,Nb,V)(C,N) is concentrated. The average composition of the single Ti-V-rich phase is (Ti0.511V0.356Nb0.133)(C x N y ), whereas that for the single Nb-rich phase is (Ti0.061V0.263Nb0.676)(C x N y ). The calculation results based on the Scheil-Gulliver model in the Thermo-Calc software combining with the thermal stability experiments show that the large phases precipitate during the solidification process. With the development of solidification, the Ti-V-rich phase precipitates first and becomes homogeneous during the subsequent temperature reduction and heat treatment processes. The Nb-rich phase appears later.

Modeling Nonlinear Elastic-plastic Behavior of RDX Single Crystals During Indentation

DTIC Science & Technology

2012-01-01

single crystals has also been probed using shock experiments (6, 12) and molecular dynamics simulations (12–14). RDX undergoes a polymorphic phase...Patterson, J.; Dreger, Z.; Gupta, Y. Shock-wave Induced Phase Transition in RDX Single Crystals. J. Phys. Chem. B 2007, 111, 10897–10904. 17. Bedrov, D...and Volume Compression of β - HMX and RDX . In Proc. Int. Symp. High Dynamic Pressures; Commissariat a l’Energie Atomique: Paris, 1978; pp 3–8. 24

Single crystals of selected titanates and tungstates

NASA Technical Reports Server (NTRS)

Loiacono, G. M.

1972-01-01

The compound preparation and crystal growth of a number of mixed titanate compositions was investigated. None of the compounds studied were found to melt congruently and therefore, crystal growth was extremely difficult. Various single crystal preparation methods always resulted in mixed phases from which 1-2 mm size crystals could be separated. It is concluded from this study that before successful single crystal growth can be accomplished, a detailed study of the phase diagrams in each of the systems of interest must be completed.

A Study of Three Phase and Single Phase High Frequency Distribution Systems

DTIC Science & Technology

1989-09-20

single Schwarz converter which operates in a variable frequency mode and acts as a regulated dc power supply . This mode of operation is used to maintain a...conditioning stages. The first stage contains a single Schwarz converter which operates in a variable frequency mode and acts as a regulated dc power supply ...dependent upon the amount of current ripple the capacitor must sink. This determines the capacitor heating since the power dissipated is equal to 2R

Dielectric and domain studies on Fe doped KNbO3 single crystal

NASA Astrophysics Data System (ADS)

Shamkuwar, Sanjaykumar H.; Patil, Naresh M.; Korde, Vivek B.; Pradnyakar, Namrata V.

2018-05-01

Synthesis of Fe doped KNbO3 single crystals by flux method is reported here. The effect of Fe-doping on phase transition temperatures of KNbO3 single crystals was investigated using dielectric studies. The phase transition temperatures were found to be 225°C and 425°C which almost same as reported by others. The domain studies were carried out using metallurgical microscope and it shows the presence of 60° and 90° domains in the grown crystals.

CO2-laser ablation of Bi-Sr-Ca-Cu oxide by millisecond pulse lengths

NASA Astrophysics Data System (ADS)

Meskoob, M.; Honda, T.; Safari, A.; Wachtman, J. B.; Danforth, S.; Wilkens, B. J.

1990-03-01

We have achieved ablation of Bi-Sr-Ca-Cu oxide from single targets of superconducting pellets by CO2-laser pulses of l ms length to grow superconducting thin films. Upon annealing, the 6000-Å thin films have a Tc (onset) of 90 K and zero resistance at 78 K. X-ray diffraction patterns indicate the growth of single-phase thin films. This technique allows growth of uniform single-phase superconducting thin films of lateral area greater than 1 cm2.

Mixed response and time-to-event endpoints for multistage single-arm phase II design.

PubMed

Lai, Xin; Zee, Benny Chung-Ying

2015-06-04

The objective of phase II cancer clinical trials is to determine if a treatment has sufficient activity to warrant further study. The efficiency of a conventional phase II trial design has been the object of considerable debate, particularly when the study regimen is characteristically cytostatic. At the time of development of a phase II cancer trial, we accumulated clinical experience regarding the time to progression (TTP) for similar classes of drugs and for standard therapy. By considering the time to event (TTE) in addition to the tumor response endpoint, a mixed-endpoint phase II design may increase the efficiency and ability of selecting promising cytotoxic and cytostatic agents for further development. We proposed a single-arm phase II trial design by extending the Zee multinomial method to fully use mixed endpoints with tumor response and the TTE. In this design, the dependence between the probability of response and the TTE outcome is modeled through a Gaussian copula. Given the type I and type II errors and the hypothesis as defined by the response rate (RR) and median TTE, such as median TTP, the decision rules for a two-stage phase II trial design can be generated. We demonstrated through simulation that the proposed design has a smaller expected sample size and higher early stopping probability under the null hypothesis than designs based on a single-response endpoint or a single TTE endpoint. The proposed design is more efficient for screening new cytotoxic or cytostatic agents and less likely to miss an effective agent than the alternative single-arm design.

30 CFR 75.806 - Connection of single-phase loads.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Connection of single-phase loads. 75.806 Section 75.806 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution...

High Performance Relaxor-Based Ferroelectric Single Crystals for Ultrasonic Transducer Applications

PubMed Central

Chen, Yan; Lam, Kwok-Ho; Zhou, Dan; Yue, Qingwen; Yu, Yanxiong; Wu, Jinchuan; Qiu, Weibao; Sun, Lei; Zhang, Chao; Luo, Haosu; Chan, Helen L. W.; Dai, Jiyan

2014-01-01

Relaxor-based ferroelectric single crystals Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) have drawn much attention in the ferroelectric field because of their excellent piezoelectric properties and high electromechanical coupling coefficients (d33∼2000 pC/N, kt∼60%) near the morphotropic phase boundary (MPB). Ternary Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) single crystals also possess outstanding performance comparable with PMN-PT single crystals, but have higher phase transition temperatures (rhombohedral to tetragonal Trt, and tetragonal to cubic Tc) and larger coercive field Ec. Therefore, these relaxor-based single crystals have been extensively employed for ultrasonic transducer applications. In this paper, an overview of our work and perspectives on using PMN-PT and PIN-PMN-PT single crystals for ultrasonic transducer applications is presented. Various types of single-element ultrasonic transducers, including endoscopic transducers, intravascular transducers, high-frequency and high-temperature transducers fabricated using the PMN-PT and PIN-PMN-PT crystals and their 2-2 and 1-3 composites are reported. Besides, the fabrication and characterization of the array transducers, such as phased array, cylindrical shaped linear array, high-temperature linear array, radial endoscopic array, and annular array, are also addressed. PMID:25076222

Single-phase helium recooling in a Tevatron spool piece

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klebaner, A.L.

2000-01-27

Plans call for upgrading existing Tevatron spool pieces by adding a single-phase to two-phase heat exchanger or recooler. This will enhance the single-phase to two-phase heat transfer and, along with other upgrades, allow for higher energy beam in the upcoming run. The performance of the heat exchanger was predicted numerically using a multi-node finite difference model. One Tevatron spool piece was modified to incorporate the recooler. Performance tests were conducted on this modified spool at the Magnet Test Facility within Technical Division in March and April 1999. The present paper reviews the design of the Tevatron spool recooler. The discussionmore » includes: a technical description of a Tevatron spool; the heat exchanger mathematical model; design criteria and constraints; fabrication and assembly procedure; tests and performance analysis.« less

Fabrication of single domain GdBCO bulk superconductors by a new modified TSIG technique

NASA Astrophysics Data System (ADS)

Yang, W. M.; Zhi, X.; Chen, S. L.; Wang, M.; Li, J. W.; Ma, J.; Chao, X. X.

2014-01-01

Single domain GdBCO bulk superconductors have been fabricated with new and traditional solid phases by a top seeded infiltration and growth (TSIG) process technique. In the conventional TSIG process, three types of powders, such as Gd2BaCuO5, GdBa2Cu3O7-x and Ba3Cu5O8, must be prepared, but in our new modified TSIG technique, only BaCuO2 powders are required during the fabrication of the single domain GdBCO bulk superconductors. The solid phase used in the conventional process is Gd2BaCuO5 instead of the solid phase (Gd2O3 + BaCuO2) utilized in the new process. The liquid phase used in the conventional process is a mixture of (GdBa2Cu3O7-x + Ba3Cu5O8), and the liquid phase in the new process is a mixture of (Gd2O3 + 10BaCuO2 + 6CuO). Single domain GdBCO bulk superconductors have been fabricated with the new solid and liquid phases. The levitation force of the GdBCO bulk samples fabricated by the new solid phase is 28 N, which is slightly higher than that of the samples fabricated using the conventional solid phases (26 N). The microstructure and the levitation force of the samples indicate that this new method can greatly simplify the fabrication process, introduce nanometer-sized flux centers, improve the levitation force and working efficiency, and greatly reduce the cost of fabrication of single domain GdBCO bulk superconductors by the TSIG process.

Berry Phase in Lattice QCD.

PubMed

Yamamoto, Arata

2016-07-29

We propose the lattice QCD calculation of the Berry phase, which is defined by the ground state of a single fermion. We perform the ground-state projection of a single-fermion propagator, construct the Berry link variable on a momentum-space lattice, and calculate the Berry phase. As the first application, the first Chern number of the (2+1)-dimensional Wilson fermion is calculated by the Monte Carlo simulation.

Fabrication of tensile-strained single-crystalline GeSn on transparent substrate by nucleation-controlled liquid-phase crystallization

NASA Astrophysics Data System (ADS)

Oka, Hiroshi; Amamoto, Takashi; Koyama, Masahiro; Imai, Yasuhiko; Kimura, Shigeru; Hosoi, Takuji; Shimura, Takayoshi; Watanabe, Heiji

2017-01-01

We developed a method of forming single-crystalline germanium-tin (GeSn) alloy on transparent substrates that is based on liquid-phase crystallization. By controlling and designing nucleation during the melting growth process, a highly tensile-strained single-crystalline GeSn layer was grown on a quartz substrate without using any crystal-seeds or catalysts. The peak field-effect hole mobility of 423 cm2/V s was obtained for a top-gate single-crystalline GeSn MOSFET on a quartz substrate with a Sn content of 2.6%, indicating excellent crystal quality and mobility enhancement due to Sn incorporation and tensile strain.

Design and performance analysis of generalised integrator-based controller for grid connected PV system

NASA Astrophysics Data System (ADS)

Saxena, Hemant; Singh, Alka; Rai, J. N.

2018-07-01

This article discusses the design and control of a single-phase grid-connected photovoltaic (PV) system. A 5-kW PV system is designed and integrated at the DC link of an H-bridge voltage source converter (VSC). The control of the VSC and switching logic is modelled using a generalised integrator (GI). The use of GI or its variants such as second-order GI have recently evolved for synchronisation and are being used as phase locked loop (PLL) circuits for grid integration. Design of PLL circuits and the use of transformations such as Park's and Clarke's are much easier in three-phase systems. But obtaining in-phase and quadrature components becomes an important and challenging issue in single-phase systems. This article addresses this issue and discusses an altogether different application of GI for the design of compensator based on the extraction of in-phase and quadrature components. GI is frequently used as a PLL; however, in this article, it is not used for synchronisation purposes. A new controller has been designed for a single-phase grid-connected PV system working as a single-phase active compensator. Extensive simulation results are shown for the working of integrated PV system under different atmospheric and operating conditions during daytime as well as night conditions. Experimental results showing the proposed control approach are presented and discussed for the hardware set-up developed in the laboratory.

Preliminary Phase Field Computational Model Development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Yulan; Hu, Shenyang Y.; Xu, Ke

2014-12-15

This interim report presents progress towards the development of meso-scale models of magnetic behavior that incorporate microstructural information. Modeling magnetic signatures in irradiated materials with complex microstructures (such as structural steels) is a significant challenge. The complexity is addressed incrementally, using the monocrystalline Fe (i.e., ferrite) film as model systems to develop and validate initial models, followed by polycrystalline Fe films, and by more complicated and representative alloys. In addition, the modeling incrementally addresses inclusion of other major phases (e.g., martensite, austenite), minor magnetic phases (e.g., carbides, FeCr precipitates), and minor nonmagnetic phases (e.g., Cu precipitates, voids). The focus ofmore » the magnetic modeling is on phase-field models. The models are based on the numerical solution to the Landau-Lifshitz-Gilbert equation. From the computational standpoint, phase-field modeling allows the simulation of large enough systems that relevant defect structures and their effects on functional properties like magnetism can be simulated. To date, two phase-field models have been generated in support of this work. First, a bulk iron model with periodic boundary conditions was generated as a proof-of-concept to investigate major loop effects of single versus polycrystalline bulk iron and effects of single non-magnetic defects. More recently, to support the experimental program herein using iron thin films, a new model was generated that uses finite boundary conditions representing surfaces and edges. This model has provided key insights into the domain structures observed in magnetic force microscopy (MFM) measurements. Simulation results for single crystal thin-film iron indicate the feasibility of the model for determining magnetic domain wall thickness and mobility in an externally applied field. Because the phase-field model dimensions are limited relative to the size of most specimens used in experiments, special experimental methods were devised to create similar boundary conditions in the iron films. Preliminary MFM studies conducted on single and polycrystalline iron films with small sub-areas created with focused ion beam have correlated quite well qualitatively with phase-field simulations. However, phase-field model dimensions are still small relative to experiments thus far. We are in the process of increasing the size of the models and decreasing specimen size so both have identical dimensions. Ongoing research is focused on validation of the phase-field model. Validation is being accomplished through comparison with experimentally obtained MFM images (in progress), and planned measurements of major hysteresis loops and first order reversal curves. Extrapolation of simulation sizes to represent a more stochastic bulk-like system will require sampling of various simulations (i.e., with single non-magnetic defect, single magnetic defect, single grain boundary, single dislocation, etc.) with distributions of input parameters. These outputs can then be compared to laboratory magnetic measurements and ultimately to simulate magnetic Barkhausen noise signals.« less

Single Sublattice Endotaxial Phase Separation Driven by Charge Frustration in a Complex Oxide

PubMed Central

2013-01-01

Complex transition-metal oxides are important functional materials in areas such as energy and information storage. The cubic ABO3 perovskite is an archetypal example of this class, formed by the occupation of small octahedral B-sites within an AO3 network defined by larger A cations. We show that introduction of chemically mismatched octahedral cations into a cubic perovskite oxide parent phase modifies structure and composition beyond the unit cell length scale on the B sublattice alone. This affords an endotaxial nanocomposite of two cubic perovskite phases with distinct properties. These locally B-site cation-ordered and -disordered phases share a single AO3 network and have enhanced stability against the formation of a competing hexagonal structure over the single-phase parent. Synergic integration of the distinct properties of these phases by the coherent interfaces of the composite produces solid oxide fuel cell cathode performance superior to that expected from the component phases in isolation. PMID:23750709

Phase formation and UV luminescence of Gd{sup 3+} doped perovskite-type YScO{sub 3}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shimizu, Yuhei; Ueda, Kazushige, E-mail: kueda@che.kyutech.ac.jp

Synthesis of pure and Gd{sup 3+}doped perovskite-type YScO{sub 3} was attempted by a polymerized complex (PC) method and solid state reaction (SSR) method. Crystalline phases and UV luminescence of samples were examined with varying heating temperatures. The perovskite-type single phase was not simply formed in the SSR method, as reported in some literatures, and two cubic C-type phases of starting oxide materials remained forming slightly mixed solid solutions. UV luminescence of Gd{sup 3+} doped samples increased with an increase in heating temperatures and volume of the perovskite-type phase. In contrast, a non-crystalline precursor was crystallized to a single C-type phasemore » at 800 °C in the PC method forming a completely mixed solid solution. Then, the phase of perovskite-type YScO{sub 3} formed at 1200 °C and its single phase was obtained at 1400 °C. It was revealed that high homogeneousness of cations was essential to generate the single perovskite-phase of YScO{sub 3}. Because Gd{sup 3+} ions were also dissolved into the single C-type phase in Gd{sup 3+} doped samples, intense UV luminescence was observed above 800 °C in both C-type phase and perovskite-type phase. - Graphical abstract: A pure perovskite-type YScO{sub 3} phase was successfully synthesized by a polymerized complex (PC) method. The perovskite-type YScO{sub 3} was generated through a solid solution of C-type (Y{sub 0.5}Sc{sub 0.5}){sub 2}O{sub 3} with drastic change of morphology. The PC method enabled a preparation of the single phase of the perovskite-type YScO{sub 3} at lower temperature and in shorter heating time. Gd{sup 3+} doped perovskite-type YScO{sub 3} was found to show a strong sharp UV emission at 314 nm. - Highlights: • Pure YScO{sub 3} phase was successfully synthesized by polymerized complex (PC) method. • Pure perovskite-type YScO{sub 3} phase was generated from pure C-type (Y{sub 0.5}Sc{sub 0.5}){sub 2}O{sub 3} one. • YScO{sub 3} was obtained at lower temperature and in shorter heating time by PC method. • Perovskite-type YScO{sub 3}:Gd{sup 3+} was found to show strong sharp UV emission at 314 nm.« less

Optimization of the crystal growth of the superconductor CaKFe 4 As 4 from solution in the FeAs - CaFe 2 As 2 - KFe 2 As 2 system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meier, W. R.; Kong, T.; Bud'ko, S. L.

Measurements of the anisotropic properties of single crystals play a crucial role in probing the physics of new materials. Determining a growth protocol that yields suitable high-quality single crystals can be particularly challenging for multicomponent compounds. Here we present a case study of how we refined a procedure to grow single crystals of CaKFe 4As 4 from a high temperature, quaternary liquid solution rich in iron and arsenic (“FeAs self-flux”). Temperature dependent resistance and magnetization measurements are emphasized, in addition to the x-ray diffraction, to detect intergrown CaKFe 4As 4, CaFe 2As 2, and KFe 2As 2 within what appearmore » to be single crystals. Guided by the rules of phase equilibria and these data, we adjusted growth parameters to suppress formation of the impurity phases. The resulting optimized procedure yielded phase-pure single crystals of CaKFe 4As 4. In conclusion, this optimization process offers insight into the growth of quaternary compounds and a glimpse of the four-component phase diagram in the pseudoternary FeAs–CaFe 2As 2–KFe 2As 2 system.« less

Analytical studies on the crystal melt interface shape in the Czochralski process for oxide single crystals

NASA Astrophysics Data System (ADS)

Jeong, Ja Hoon; Kang, In Seok

2000-09-01

Effects of the operating conditions on the crystal-melt interface shape are analytically investigated for the Czochralski process of the oxide single crystals. The ideas, which were used for the silicon single-crystal growth by Jeong et al. (J. Crystal Growth 177 (1997) 157), are extended to the oxide single-crystal growth problem by considering the internal radiation in the crystal phase and the melt phase heat transfer with the high Prandtl number. The interface shape is approximated in the simplest form as a quadratic function of radial position and an expression for the deviation from the flat interface shape is derived as a function of operating conditions. The radiative heat transfer rate between the interface and the ambient is computed by calculating the view factors for the curved interface shape with the assumption that the crystal phase is completely transparent. For the melt phase, the well-known results from the thermal boundary layer analysis are applied for the asymptotic case of high Prandtl number based on the idea that the flow field near the crystal-melt interface can be modeled as either a uniaxial or a biaxial flow. Through this work, essential information on the interface shape deformation and the effects of operating conditions are brought out for the oxide single-crystal growth.

Optimization of the crystal growth of the superconductor CaKFe 4 As 4 from solution in the FeAs - CaFe 2 As 2 - KFe 2 As 2 system

DOE PAGES

Meier, W. R.; Kong, T.; Bud'ko, S. L.; ...

2017-06-19

Measurements of the anisotropic properties of single crystals play a crucial role in probing the physics of new materials. Determining a growth protocol that yields suitable high-quality single crystals can be particularly challenging for multicomponent compounds. Here we present a case study of how we refined a procedure to grow single crystals of CaKFe 4As 4 from a high temperature, quaternary liquid solution rich in iron and arsenic (“FeAs self-flux”). Temperature dependent resistance and magnetization measurements are emphasized, in addition to the x-ray diffraction, to detect intergrown CaKFe 4As 4, CaFe 2As 2, and KFe 2As 2 within what appearmore » to be single crystals. Guided by the rules of phase equilibria and these data, we adjusted growth parameters to suppress formation of the impurity phases. The resulting optimized procedure yielded phase-pure single crystals of CaKFe 4As 4. In conclusion, this optimization process offers insight into the growth of quaternary compounds and a glimpse of the four-component phase diagram in the pseudoternary FeAs–CaFe 2As 2–KFe 2As 2 system.« less

Massively parallel haplotyping on microscopic beads for the high-throughput phase analysis of single molecules.

PubMed

Boulanger, Jérôme; Muresan, Leila; Tiemann-Boege, Irene

2012-01-01

In spite of the many advances in haplotyping methods, it is still very difficult to characterize rare haplotypes in tissues and different environmental samples or to accurately assess the haplotype diversity in large mixtures. This would require a haplotyping method capable of analyzing the phase of single molecules with an unprecedented throughput. Here we describe such a haplotyping method capable of analyzing in parallel hundreds of thousands single molecules in one experiment. In this method, multiple PCR reactions amplify different polymorphic regions of a single DNA molecule on a magnetic bead compartmentalized in an emulsion drop. The allelic states of the amplified polymorphisms are identified with fluorescently labeled probes that are then decoded from images taken of the arrayed beads by a microscope. This method can evaluate the phase of up to 3 polymorphisms separated by up to 5 kilobases in hundreds of thousands single molecules. We tested the sensitivity of the method by measuring the number of mutant haplotypes synthesized by four different commercially available enzymes: Phusion, Platinum Taq, Titanium Taq, and Phire. The digital nature of the method makes it highly sensitive to detecting haplotype ratios of less than 1:10,000. We also accurately quantified chimera formation during the exponential phase of PCR by different DNA polymerases.

A novel single-phase flux-switching permanent magnet linear generator used for free-piston Stirling engine

NASA Astrophysics Data System (ADS)

Zheng, Ping; Sui, Yi; Tong, Chengde; Bai, Jingang; Yu, Bin; Lin, Fei

2014-05-01

This paper investigates a novel single-phase flux-switching permanent-magnet (PM) linear machine used for free-piston Stirling engines. The machine topology and operating principle are studied. A flux-switching PM linear machine is designed based on the quasi-sinusoidal speed characteristic of the resonant piston. Considering the performance of back electromotive force and thrust capability, some leading structural parameters, including the air gap length, the PM thickness, the ratio of the outer radius of mover to that of stator, the mover tooth width, the stator tooth width, etc., are optimized by finite element analysis. Compared with conventional three-phase moving-magnet linear machine, the proposed single-phase flux-switching topology shows advantages in less PM use, lighter mover, and higher volume power density.

Snow particles extracted from X-ray computed microtomography imagery and their single-scattering properties

NASA Astrophysics Data System (ADS)

Ishimoto, Hiroshi; Adachi, Satoru; Yamaguchi, Satoru; Tanikawa, Tomonori; Aoki, Teruo; Masuda, Kazuhiko

2018-04-01

Sizes and shapes of snow particles were determined from X-ray computed microtomography (micro-CT) images, and their single-scattering properties were calculated at visible and near-infrared wavelengths using a Geometrical Optics Method (GOM). We analyzed seven snow samples including fresh and aged artificial snow and natural snow obtained from field samples. Individual snow particles were numerically extracted, and the shape of each snow particle was defined by applying a rendering method. The size distribution and specific surface area distribution were estimated from the geometrical properties of the snow particles, and an effective particle radius was derived for each snow sample. The GOM calculations at wavelengths of 0.532 and 1.242 μm revealed that the realistic snow particles had similar scattering phase functions as those of previously modeled irregular shaped particles. Furthermore, distinct dendritic particles had a characteristic scattering phase function and asymmetry factor. The single-scattering properties of particles of effective radius reff were compared with the size-averaged single-scattering properties. We found that the particles of reff could be used as representative particles for calculating the average single-scattering properties of the snow. Furthermore, the single-scattering properties of the micro-CT particles were compared to those of particle shape models using our current snow retrieval algorithm. For the single-scattering phase function, the results of the micro-CT particles were consistent with those of a conceptual two-shape model. However, the particle size dependence differed for the single-scattering albedo and asymmetry factor.

Rapid one-step purification of single-cells encapsulated in alginate microcapsules from oil to aqueous phase using a hydrophobic filter paper: implications for single-cell experiments.

PubMed

Lee, Do-Hyun; Jang, Miran; Park, Je-Kyun

2014-10-01

By virtue of the biocompatibility and physical properties of hydrogel, picoliter-sized hydrogel microcapsules have been considered to be a biometric signature containing several features similar to that of encapsulated single cells, including phenotype, viability, and intracellular content. To maximize the experimental potential of encapsulating cells in hydrogel microcapsules, a method that enables efficient hydrogel microcapsule purification from oil is necessary. Current methods based on centrifugation for the conventional stepwise rinsing of oil, are slow and laborious and decrease the monodispersity and yield of the recovered hydrogel microcapsules. To remedy these shortcomings we have developed a simple one-step method to purify alginate microcapsules, containing a single live cell, from oil to aqueous phase. This method employs oil impregnation using a commercially available hydrophobic filter paper without multistep centrifugal purification and complicated microchannel networks. The oil-suspended alginate microcapsules encapsulating single cells from mammalian cancer cell lines (MCF-7, HepG2, and U937) and microorganisms (Chlorella vulgaris) were successfully exchanged to cell culture media by quick (~10 min) depletion of the surrounding oil phase without coalescence of neighboring microcapsules. Cell proliferation and high integrity of the microcapsules were also demonstrated by long-term incubation of microcapsules containing a single live cell. We expect that this method for the simple and rapid purification of encapsulated single-cell microcapsules will attain widespread adoption, assisting cell biologists and clinicians in the development of single-cell experiments. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Elastic excitations in BaTiO3 single crystals and ceramics: Mobile domain boundaries and polar nanoregions observed by resonant ultrasonic spectroscopy

NASA Astrophysics Data System (ADS)

Salje, Ekhard K. H.; Carpenter, Michael A.; Nataf, Guillaume F.; Picht, Gunnar; Webber, Kyle; Weerasinghe, Jeevaka; Lisenkov, S.; Bellaiche, L.

2013-01-01

The dynamic properties of elastic domain walls in BaTiO3 were investigated using resonance ultrasonic spectroscopy (RUS). The sequence of phase transitions is characterized by minima in the temperature dependence of RUS resonance frequencies and changes in Q factors (resonance damping). Damping is related to the friction of mobile twin boundaries (90° ferroelectric walls) and distorted polar nanoregions (PNRs) in the cubic phase. Damping is largest in the tetragonal phase of ceramic materials but very low in single crystals. Damping is also small in the low-temperature phases of the ceramic sample and slightly increases with decreasing temperature in the single crystal. The phase angle between the real and imaginary part of the dynamic response function changes drastically in the cubic and tetragonal phases and remains constant in the orthorhombic phase. Other phases show a moderate dependence of the phase angle on temperature showing systematic changes of twin microstructures. Mobile twin boundaries (or sections of twin boundaries such as kinks inside twin walls) contribute strongly to the energy dissipation of the forced oscillation while the reduction in effective modulus due to relaxing twin domains is weak. Single crystals and ceramics show strong precursor softening in the cubic phase related to polar nanoregions (PNRs). The effective modulus decreases when the transition point of the cubic-tetragonal transformation is approached from above. The precursor softening follows temperature dependence very similar to recent results from Brillouin scattering. Between the Burns temperature (≈586 K) and Tc at 405 K, we found a good fit of the squared RUS frequency [˜Δ (C11-C12)] to a Vogel-Fulcher process with an activation energy of ˜0.2 eV. Finally, some first-principles-based effective Hamiltonian computations were carried out in BaTiO3 single domains to explain some of these observations in terms of the dynamics of the soft mode and central mode.

Single-phase power distribution system power flow and fault analysis

NASA Technical Reports Server (NTRS)

Halpin, S. M.; Grigsby, L. L.

1992-01-01

Alternative methods for power flow and fault analysis of single-phase distribution systems are presented. The algorithms for both power flow and fault analysis utilize a generalized approach to network modeling. The generalized admittance matrix, formed using elements of linear graph theory, is an accurate network model for all possible single-phase network configurations. Unlike the standard nodal admittance matrix formulation algorithms, the generalized approach uses generalized component models for the transmission line and transformer. The standard assumption of a common node voltage reference point is not required to construct the generalized admittance matrix. Therefore, truly accurate simulation results can be obtained for networks that cannot be modeled using traditional techniques.

Temperature and electric-field induced phase transition behavior and electrical properties of [001]-oriented 0.23Pb(In1/2Nb1/2)O3-0.47Pb(Mg1/3Nb2/3)O3-0.3PbTiO3-Mn single crystals

NASA Astrophysics Data System (ADS)

Zhang, Zhang; Chen, Jianwei; Xu, Jialin; Li, Xiaobing; Luo, Haosu

2017-12-01

The temperature and electric-field induced phase transition behavior and dielectric, piezoelectric, and ferroelectric properties of [001]-oriented 0.23Pb(In1/2Nb1/2)O3-0.47Pb(Mg1/3Nb2/3)O3-0.3PbTiO3-Mn (PIMNT-Mn) single crystals were investigated. Dielectric performance analysis and temperature-dependent Raman spectra show three apparent ferroelectric phase transition temperatures around 120 °C(TR-M),145 °C(TM-T), and 170 °C(TT-C), respectively. In addition, the temperature dependence of the relative Raman intensities of Lorentzian peaks indicates the poled PIMNT-Mn single crystals exhibit rhombohedral(R) → monoclinic(M) → tetragonal(T) → cubic(C) phase transition path. The electrical properties of the PIMNT-Mn single crystals such as the longitudinal electrostrictive coefficient (Q), the converse piezoelectric constant (d33), and the maximum strain value (Smax%) have changed abnormally around the phase transition temperatures (TR-M and TM-T).

Algorithms for image recovery calculation in extended single-shot phase-shifting digital holography

NASA Astrophysics Data System (ADS)

Hasegawa, Shin-ya; Hirata, Ryo

2018-04-01

The single-shot phase-shifting method of image recovery using an inclined reference wave has the advantages of reducing the effects of vibration, being capable of operating in real time, and affording low-cost sensing. In this method, relatively low reference angles compared with that in the conventional method using phase shift between three or four pixels has been required. We propose an extended single-shot phase-shifting technique which uses the multiple-step phase-shifting algorithm and the corresponding multiple pixels which are the same as that of the period of an interference fringe. We have verified the theory underlying this recovery method by means of Fourier spectral analysis and its effectiveness by evaluating the visibility of the image using a high-resolution pattern. Finally, we have demonstrated high-contrast image recovery experimentally using a resolution chart. This method can be used in a variety of applications such as color holographic interferometry.

Target-in-the-loop high-power adaptive phase-locked fiber laser array using single-frequency dithering technique

NASA Astrophysics Data System (ADS)

Tao, R.; Ma, Y.; Si, L.; Dong, X.; Zhou, P.; Liu, Z.

2011-11-01

We present a theoretical and experimental study of a target-in-the-loop (TIL) high-power adaptive phase-locked fiber laser array. The system configuration of the TIL adaptive phase-locked fiber laser array is introduced, and the fundamental theory for TIL based on the single-dithering technique is deduced for the first time. Two 10-W-level high-power fiber amplifiers are set up and adaptive phase locking of the two fiber amplifiers is accomplished successfully by implementing a single-dithering algorithm on a signal processor. The experimental results demonstrate that the optical phase noise for each beam channel can be effectively compensated by the TIL adaptive optics system under high-power applications and the fringe contrast on a remotely located extended target is advanced from 12% to 74% for the two 10-W-level fiber amplifiers.

Motion compensation via redundant-wavelet multihypothesis.

PubMed

Fowler, James E; Cui, Suxia; Wang, Yonghui

2006-10-01

Multihypothesis motion compensation has been widely used in video coding with previous attention focused on techniques employing predictions that are diverse spatially or temporally. In this paper, the multihypothesis concept is extended into the transform domain by using a redundant wavelet transform to produce multiple predictions that are diverse in transform phase. The corresponding multiple-phase inverse transform implicitly combines the phase-diverse predictions into a single spatial-domain prediction for motion compensation. The performance advantage of this redundant-wavelet-multihypothesis approach is investigated analytically, invoking the fact that the multiple-phase inverse involves a projection that significantly reduces the power of a dense-motion residual modeled as additive noise. The analysis shows that redundant-wavelet multihypothesis is capable of up to a 7-dB reduction in prediction-residual variance over an equivalent single-phase, single-hypothesis approach. Experimental results substantiate the performance advantage for a block-based implementation.

Design of three-phased SPWM based on AT89C52

NASA Astrophysics Data System (ADS)

Wu, Xiaorui

2018-05-01

According to the AT89C52 and the area equivalent principle, a three phase SPWM algorithm based on the 8 bit single chip is obtained. Through computer programming, three-phase SPWM wave generated by a single chip microcomputer is applied to the circuit of the static reactive power generator. The result shows that this method is feasible and can reduce the cost of SVG.

Magnetic antenna excitation of whistler modes. III. Group and phase velocities of wave packets

NASA Astrophysics Data System (ADS)

Urrutia, J. M.; Stenzel, R. L.

2015-07-01

The properties of whistler modes excited by single and multiple magnetic loop antennas have been investigated in a large laboratory plasma. A single loop excites a wavepacket, but an array of loops across the ambient magnetic field B0 excites approximate plane whistler modes. The single loop data are measured. The array patterns are obtained by linear superposition of experimental data shifted in space and time, which is valid in a uniform plasma and magnetic field for small amplitude waves. Phasing the array changes the angle of wave propagation. The antennas are excited by an rf tone burst whose propagating envelope and oscillations yield group and phase velocities. A single loop antenna with dipole moment across B0 excites wave packets whose topology resembles m = 1 helicon modes, but without radial boundaries. The phase surfaces are conical with propagation characteristics of Gendrin modes. The cones form near the antenna with comparable parallel and perpendicular phase velocities. A physical model for the wave excitation is given. When a wave burst is applied to a phased antenna array, the wave front propagates both along the array and into the plasma forming a "whistler wing" at the front. These laboratory observations may be relevant for excitation and detection of whistler modes in space plasmas.

Single particle analysis based on Zernike phase contrast transmission electron microscopy.

PubMed

Danev, Radostin; Nagayama, Kuniaki

2008-02-01

We present the first application of Zernike phase-contrast transmission electron microscopy to single-particle 3D reconstruction of a protein, using GroEL chaperonin as the test specimen. We evaluated the performance of the technique by comparing 3D models derived from Zernike phase contrast imaging, with models from conventional underfocus phase contrast imaging. The same resolution, about 12A, was achieved by both imaging methods. The reconstruction based on Zernike phase contrast data required about 30% fewer particles. The advantages and prospects of each technique are discussed.

Gas-Liquid Flows and Phase Separation

NASA Technical Reports Server (NTRS)

McQuillen, John

2004-01-01

Common issues for space system designers include:Ability to Verify Performance in Normal Gravity prior to Deployment; System Stability; Phase Accumulation & Shedding; Phase Separation; Flow Distribution through Tees & Manifolds Boiling Crisis; Heat Transfer Coefficient; and Pressure Drop.The report concludes:Guidance similar to "A design that operates in a single phase is less complex than a design that has two-phase flow" is not always true considering the amount of effort spent on pressurizing, subcooling and phase separators to ensure single phase operation. While there is still much to learn about two-phase flow in reduced gravity, we have a good start. Focus now needs to be directed more towards system level problems .

Development of n- and p-type Doped Perovskite Single Crystals Using Solid-State Single Crystal Growth (SSCG) Technique

DTIC Science & Technology

2017-10-09

doped BaTiO3 single crystal) could be also fabricated by using a BaTiO3 ceramics with the same compositional gradient (Fig. 8). This result has...piezoelectric applications. Compositionally PZT ceramics lie near the MPB between the tetragonal and rhombohedral phases and MPB compositions ...single crystal growth) technique are suitable to grow a variety of “n- and p-type doped” perovskite single crystals of complicated compositions . The

Continuous-Wave Single-Frequency Operation of Fabry-Perot Laser Diodes by Self-Injection Phase Locking Using Feedback from a Fiber Bragg Grating

NASA Technical Reports Server (NTRS)

Duerksen, Gary L.; Krainak, Michael A.

1998-01-01

Single-frequency operation of uncoated Fabry-Perot laser diodes is demonstrated by phase- locking the laser oscillations through self-injection seeding with feedback from a fiber Bragg grating. By precisely tuning the laser temperature so that an axial-mode coincides with the short-wavelength band edge of the grating, the phase of the feedback is made conjugate to that of the axial mode, locking the phase of the laser oscillations to that mode.

Diagnostic performance of a streamlined 18F-choline PET-CT protocol for the detection of prostate carcinoma recurrence in combination with appropriate-use criteria.

PubMed

Frood, R; Baren, J; McDermott, G; Bottomley, D; Patel, C; Scarsbrook, A

2018-04-30

To evaluate the efficacy of single time-point half-body (skull base to thighs) fluorine-18 choline positron emission tomography-computed tomography (PET-CT) compared to a triple-phase acquisition protocol in the detection of prostate carcinoma recurrence. Consecutive choline PET-CT studies performed at a single tertiary referral centre in patients with biochemical recurrence of prostate carcinoma between September 2012 and March 2017 were reviewed retrospectively. The indication for the study, imaging protocol used, imaging findings, whether management was influenced by the PET-CT, and subsequent patient outcome were recorded. Ninety-one examinations were performed during the study period; 42 were carried out using a triple-phase protocol (dynamic pelvic imaging for 20 minutes after tracer injection, half-body acquisition at 60 minutes and delayed pelvic scan at 90 minutes) between 2012 and August 2015. Subsequently following interim review of diagnostic performance, a streamlined protocol and appropriate-use criteria were introduced. Forty-nine examinations were carried out using the single-phase protocol between 2015 and 2017. Twenty-nine (69%) of the triple-phase studies were positive for recurrence compared to 38 (78%) of the single-phase studies. Only one patient who had a single-phase study would have benefited from a dynamic acquisition, they have required no further treatment or imaging and are currently under prostate-specific antigen (PSA) surveillance. Choline PET-CT remains a useful tool for the detection of prostate recurrence when used in combination with appropriate-use criteria. Removal of dynamic and delayed acquisition phases reduces study time without adversely affecting accuracy. Benefits include shorter imaging time which improves patient comfort, reduced cost, and improved scanner efficiency. Copyright © 2018 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

From Relativistic Electrons to X-ray Phase Contrast Imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lumpkin, A. H.; Garson, A. B.; Anastasio, M. A.

2017-10-09

We report the initial demonstrations of the use of single crystals in indirect x-ray imaging for x-ray phase contrast imaging at the Washington University in St. Louis Computational Bioimaging Laboratory (CBL). Based on single Gaussian peak fits to the x-ray images, we observed a four times smaller system point spread function (21 μm (FWHM)) with the 25-mm diameter single crystals than the reference polycrystalline phosphor’s 80-μm value. Potential fiber-optic plate depth-of-focus aspects and 33-μm diameter carbon fiber imaging are also addressed.

Structure of Cs{sub 4}(HSO{sub 4}){sub 3}(H{sub 2}PO{sub 4}) single crystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Makarova, I. P., E-mail: makarova@crys.ras.ru; Grebenev, V. V.; Vasil’ev, I. I.

2016-01-15

Single crystals of Cs{sub 4}(HSO{sub 4}){sub 3}(H{sub 2}PO{sub 4}) are synthesized and studied for the first time. The new compound is found in the course of studies of the phase diagram of the CsHSO{sub 4}–CsH{sub 2}PO{sub 4}–H{sub 2}O triple system. Data on the atomic crystal structure of single-crystalline and powder specimens, as well as on structural phase transitions, are obtained.

Spatially resolved resistivity near the vortex lattice phase transition in Bi 2Sr 2CaCu 2O 8+δ single crystals

NASA Astrophysics Data System (ADS)

Berseth, V.; Indenbom, M. V.; van der Beek, C. J.; D'Anna, G.; Benoit, W.

1997-08-01

Using a multiterminal contact configuration, we investigate the local variations of the resistivity drop near the vortex lattice first order phase transition in a very homogeneous Bi2Sr2CaCu2O8+δ (BSCCO) single crystal.

Application of First Principles Model to Spacecraft Operations

NASA Technical Reports Server (NTRS)

Timmerman, Paul; Bugga, Ratnakumar; DiStefano, Salvidor

1996-01-01

Previous models use a single phase reaction; cycled cell predicts cannot be met with a single phase; interphase conversion provides means for film aging; aging cells predictions display typical behaviors: pressure changes in NiH² cells; voltage fading upon cycling; second plateau on discharge of cycled cells; negative limited behavior for Ni-Cds.

Multiple linear regression to estimate time-frequency electrophysiological responses in single trials

PubMed Central

Hu, L.; Zhang, Z.G.; Mouraux, A.; Iannetti, G.D.

2015-01-01

Transient sensory, motor or cognitive event elicit not only phase-locked event-related potentials (ERPs) in the ongoing electroencephalogram (EEG), but also induce non-phase-locked modulations of ongoing EEG oscillations. These modulations can be detected when single-trial waveforms are analysed in the time-frequency domain, and consist in stimulus-induced decreases (event-related desynchronization, ERD) or increases (event-related synchronization, ERS) of synchrony in the activity of the underlying neuronal populations. ERD and ERS reflect changes in the parameters that control oscillations in neuronal networks and, depending on the frequency at which they occur, represent neuronal mechanisms involved in cortical activation, inhibition and binding. ERD and ERS are commonly estimated by averaging the time-frequency decomposition of single trials. However, their trial-to-trial variability that can reflect physiologically-important information is lost by across-trial averaging. Here, we aim to (1) develop novel approaches to explore single-trial parameters (including latency, frequency and magnitude) of ERP/ERD/ERS; (2) disclose the relationship between estimated single-trial parameters and other experimental factors (e.g., perceived intensity). We found that (1) stimulus-elicited ERP/ERD/ERS can be correctly separated using principal component analysis (PCA) decomposition with Varimax rotation on the single-trial time-frequency distributions; (2) time-frequency multiple linear regression with dispersion term (TF-MLRd) enhances the signal-to-noise ratio of ERP/ERD/ERS in single trials, and provides an unbiased estimation of their latency, frequency, and magnitude at single-trial level; (3) these estimates can be meaningfully correlated with each other and with other experimental factors at single-trial level (e.g., perceived stimulus intensity and ERP magnitude). The methods described in this article allow exploring fully non-phase-locked stimulus-induced cortical oscillations, obtaining single-trial estimate of response latency, frequency, and magnitude. This permits within-subject statistical comparisons, correlation with pre-stimulus features, and integration of simultaneously-recorded EEG and fMRI. PMID:25665966

Thermal properties of the mixed spin-1 and spin-3/2 Ising ferrimagnetic system with two different random single-ion anisotropies

NASA Astrophysics Data System (ADS)

Pereira, J. R. V.; Tunes, T. M.; de Arruda, A. S.; Godoy, M.

2018-06-01

In this work, we have performed Monte Carlo simulations to study a mixed spin-1 and spin-3/2 Ising ferrimagnetic system on a square lattice with two different random single-ion anisotropies. This lattice is divided in two interpenetrating sublattices with spins SA = 1 in the sublattice A and SB = 3 / 2 in the sublattice B. The exchange interaction between the spins on the sublattices is antiferromagnetic (J < 0). We used two random single-ion anisotropies, DiA and DjB , on the sublattices A and B, respectively. We have determined the phase diagram of the model in the critical temperature Tc versus strength of the random single-ion anisotropy D plane and we shown that it exhibits only second-order phase transition lines. We also shown that this system displays compensation temperatures for some cases of the random single-ion distribution.

Understanding Single Adulthood.

ERIC Educational Resources Information Center

Stein, Peter J.

The life styles and life chances of the unmarried include elements of choices. Singles may be grouped and characterized according to whether their status may be considered stable or temporary. A life cycle, or continuum model of singlehood is reviewed, including its different factors, or phases. A new model for singles is proposed--a life spiral…

Novel phase diagram behavior and materials design in heterostructural semiconductor alloys

PubMed Central

Holder, Aaron M.; Siol, Sebastian; Ndione, Paul F.; Peng, Haowei; Deml, Ann M.; Matthews, Bethany E.; Schelhas, Laura T.; Toney, Michael F.; Gordon, Roy G.; Tumas, William; Perkins, John D.; Ginley, David S.; Gorman, Brian P.; Tate, Janet; Zakutayev, Andriy; Lany, Stephan

2017-01-01

Structure and composition control the behavior of materials. Isostructural alloying is historically an extremely successful approach for tuning materials properties, but it is often limited by binodal and spinodal decomposition, which correspond to the thermodynamic solubility limit and the stability against composition fluctuations, respectively. We show that heterostructural alloys can exhibit a markedly increased range of metastable alloy compositions between the binodal and spinodal lines, thereby opening up a vast phase space for novel homogeneous single-phase alloys. We distinguish two types of heterostructural alloys, that is, those between commensurate and incommensurate phases. Because of the structural transition around the critical composition, the properties change in a highly nonlinear or even discontinuous fashion, providing a mechanism for materials design that does not exist in conventional isostructural alloys. The novel phase diagram behavior follows from standard alloy models using mixing enthalpies from first-principles calculations. Thin-film deposition demonstrates the viability of the synthesis of these metastable single-phase domains and validates the computationally predicted phase separation mechanism above the upper temperature bound of the nonequilibrium single-phase region. PMID:28630928

Novel phase diagram behavior and materials design in heterostructural semiconductor alloys.

PubMed

Holder, Aaron M; Siol, Sebastian; Ndione, Paul F; Peng, Haowei; Deml, Ann M; Matthews, Bethany E; Schelhas, Laura T; Toney, Michael F; Gordon, Roy G; Tumas, William; Perkins, John D; Ginley, David S; Gorman, Brian P; Tate, Janet; Zakutayev, Andriy; Lany, Stephan

2017-06-01

Structure and composition control the behavior of materials. Isostructural alloying is historically an extremely successful approach for tuning materials properties, but it is often limited by binodal and spinodal decomposition, which correspond to the thermodynamic solubility limit and the stability against composition fluctuations, respectively. We show that heterostructural alloys can exhibit a markedly increased range of metastable alloy compositions between the binodal and spinodal lines, thereby opening up a vast phase space for novel homogeneous single-phase alloys. We distinguish two types of heterostructural alloys, that is, those between commensurate and incommensurate phases. Because of the structural transition around the critical composition, the properties change in a highly nonlinear or even discontinuous fashion, providing a mechanism for materials design that does not exist in conventional isostructural alloys. The novel phase diagram behavior follows from standard alloy models using mixing enthalpies from first-principles calculations. Thin-film deposition demonstrates the viability of the synthesis of these metastable single-phase domains and validates the computationally predicted phase separation mechanism above the upper temperature bound of the nonequilibrium single-phase region.

Novel phase diagram behavior and materials design in heterostructural semiconductor alloys

DOE PAGES

Holder, Aaron M.; Siol, Sebastian; Ndione, Paul F.; ...

2017-06-07

Structure and composition control the behavior of materials. Isostructural alloying is historically an extremely successful approach for tuning materials properties, but it is often limited by binodal and spinodal decomposition, which correspond to the thermodynamic solubility limit and the stability against composition fluctuations, respectively. We show that heterostructural alloys can exhibit a markedly increased range of metastable alloy compositions between the binodal and spinodal lines, thereby opening up a vast phase space for novel homogeneous single-phase alloys. We distinguish two types of heterostructural alloys, that is, those between commensurate and incommensurate phases. Because of the structural transition around the criticalmore » composition, the properties change in a highly nonlinear or even discontinuous fashion, providing a mechanism for materials design that does not exist in conventional isostructural alloys. The novel phase diagram behavior follows from standard alloy models using mixing enthalpies from first-principles calculations. Furthermore, thin-film deposition demonstrates the viability of the synthesis of these metastable single-phase domains and validates the computationally predicted phase separation mechanism above the upper temperature bound of the nonequilibrium single-phase region.« less

A single-phase axially-magnetized permanent-magnet oscillating machine for miniature aerospace power sources

NASA Astrophysics Data System (ADS)

Sui, Yi; Zheng, Ping; Cheng, Luming; Wang, Weinan; Liu, Jiaqi

2017-05-01

A single-phase axially-magnetized permanent-magnet (PM) oscillating machine which can be integrated with a free-piston Stirling engine to generate electric power, is investigated for miniature aerospace power sources. Machine structure, operating principle and detent force characteristic are elaborately studied. With the sinusoidal speed characteristic of the mover considered, the proposed machine is designed by 2D finite-element analysis (FEA), and some main structural parameters such as air gap diameter, dimensions of PMs, pole pitches of both stator and mover, and the pole-pitch combinations, etc., are optimized to improve both the power density and force capability. Compared with the three-phase PM linear machines, the proposed single-phase machine features less PM use, simple control and low controller cost. The power density of the proposed machine is higher than that of the three-phase radially-magnetized PM linear machine, but lower than the three-phase axially-magnetized PM linear machine.

A method for determining optimum phasing of a multiphase propulsion system for a single-stage vehicle with linearized inert weight

NASA Technical Reports Server (NTRS)

Martin, J. A.

1974-01-01

A general analytical treatment is presented of a single-stage vehicle with multiple propulsion phases. A closed-form solution for the cost and for the performance and a derivation of the optimal phasing of the propulsion are included. Linearized variations in the inert weight elements are included, and the function to be minimized can be selected. The derivation of optimal phasing results in a set of nonlinear algebraic equations for optimal fuel volumes, for which a solution method is outlined. Three specific example cases are analyzed: minimum gross lift-off weight, minimum inert weight, and a minimized general function for a two-phase vehicle. The results for the two-phase vehicle are applied to the dual-fuel rocket. Comparisons with single-fuel vehicles indicate that dual-fuel vehicles can have lower inert weight either by development of a dual-fuel engine or by parallel burning of separate engines from lift-off.

Pressure dependence of band-gap and phase transitions in bulk CuX (X = Cl, Br, I)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Azhikodan, Dilna; Nautiyal, Tashi; Sharma, S.

2016-05-06

Usually a phase transition, in theoretical studies, is explored or verified by studying the total energy as a function of the volume considering various plausible phases. The intersection point, if any, of the free energy vs. volume curves for the different phases is then the indicator of the phase transition(s). The question is, can the theoretical study of a single phase alone indicate a phase transition? i.e. can we look beyond the phase under consideration through such a study? Using density-functional theory, we report a novel approach to suggest phase transition(s) through theoretical study of a single phase. Copper halidesmore » have been engaged for this study. These are direct band-gap semiconductors, with zinc blende structure at ambient conditions, and are reported to exhibit many phase transitions. We show that the study of volume dependence of energy band-gap in a single phase facilitates looking beyond the phase under consideration. This, when translated to pressures, reflects the phase transition pressures for CuX (X = Cl, Br, I) with an encouraging accuracy. This work thus offers a simple, yet reliable, approach based on electronic structure calculations to investigate new semiconducting materials for phase changes under pressure.« less

Interface Character of Aluminum-Graphite Metal Matrix Composites.

DTIC Science & Technology

1983-01-27

studied included the commer- cial A/graphite composites; layered model systems on single crystal and poly- crystalline graphite substrates as well as...composition and thickness of the composite interface, and graphite crystal orientation. 3 For the model systems in this study , single crystal graphite...been reviewed by Kingcry. Segregation at surfaces in single- crystal MgO of Fe, Cr and Sc, which were Dresent in concentrations within the single- 3phase

Behavior of sheets from Ti-alloys by rolling and heat treatment

NASA Astrophysics Data System (ADS)

Isaenkova, M.; Perlovich, Yu.; Fesenko, V.; Gritskevich, M.; Stolbov, S.; Zaripova, M.

2017-10-01

Sheets from single- and two-phase Ti-alloys (VT1-0, Ti-22Nb-9%Zr and VT-16) were rolled at the room temperature up to various deformation degrees and annealed at temperatures 500-900 °C. The regularities of texture formation in both phases were established. In the technically pure Ti (VT1-0) with the single α-Ti phase the final stable texture component is (0001)±30-40°ND-TD<101 ¯0>. In the two-phase alloy the reorientation of basal axes of α-Ti occurs by the same trajectories as in the single phase alloy. However, in the case of two-phase alloy texture development in α-Ti stops at the intermediate stage, when this texture consists of components with rolling planes (0001)±15-20°ND-RD and (0001)±30-40°ND-TD. The stability of the first components can be provided both by the mutually balanced operation of pyramidal and basal slip systems, activity of which remains at the high deformation degree of two-phase alloy, and by the dynamic α↔β phase transformations, taking place in the distorted structures of α- and β-phases in the course of its cold rolling. At recrystallization of technically pure Ti the basal component disappears in its texture. At the same time, prismatic axes turn by angles 20÷30° depending on the heating rate of the rolled sheet and annealing temperature. At recrystallization of the two-phase Ti-alloy prismatic axes of its α-grains doesn't turn relative to their positions in the rolling texture, as it occurs in the single-phase alloy. This fact indicates to some alternative mode of arising new recrystallized grains in two-phase alloys.

Enhancement of beam pulse controllability for a single-pulse formation system of a cyclotron.

PubMed

Kurashima, Satoshi; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Okumura, Susumu; Taguchi, Mitsumasa; Fukuda, Mitsuhiro

2015-07-01

The single-pulse formation technique using a beam chopping system consisting of two types of high-voltage beam kickers was improved to enhance the quality and intensity of the single-pulse beam with a pulse interval over 1 μs at the Japan Atomic Energy Agency cyclotron facility. A contamination rate of neighboring beam bunches in the single-pulse beam was reduced to less than 0.1%. Long-term purification of the single pulse beam was guaranteed by the well-controlled magnetic field stabilization system for the cyclotron magnet. Reduction of the multi-turn extraction number for suppressing the neighboring beam bunch contamination was achieved by restriction of a beam phase width and precise optimization of a particle acceleration phase. In addition, the single-pulse beam intensity was increased by a factor of two or more by a combination of two types of beam bunchers using sinusoidal and saw-tooth voltage waveforms. Provision of the high quality intense single-pulse beam contributed to improve the accuracy of experiments for investigation of scintillation light time-profile and for neutron energy measurement by a time-of-flight method.

Enhancement of beam pulse controllability for a single-pulse formation system of a cyclotron

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurashima, Satoshi, E-mail: kurashima.satoshi@jaea.go.jp; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu

The single-pulse formation technique using a beam chopping system consisting of two types of high-voltage beam kickers was improved to enhance the quality and intensity of the single-pulse beam with a pulse interval over 1 μs at the Japan Atomic Energy Agency cyclotron facility. A contamination rate of neighboring beam bunches in the single-pulse beam was reduced to less than 0.1%. Long-term purification of the single pulse beam was guaranteed by the well-controlled magnetic field stabilization system for the cyclotron magnet. Reduction of the multi-turn extraction number for suppressing the neighboring beam bunch contamination was achieved by restriction of amore » beam phase width and precise optimization of a particle acceleration phase. In addition, the single-pulse beam intensity was increased by a factor of two or more by a combination of two types of beam bunchers using sinusoidal and saw-tooth voltage waveforms. Provision of the high quality intense single-pulse beam contributed to improve the accuracy of experiments for investigation of scintillation light time-profile and for neutron energy measurement by a time-of-flight method.« less

A two-qubit logic gate in silicon.

PubMed

Veldhorst, M; Yang, C H; Hwang, J C C; Huang, W; Dehollain, J P; Muhonen, J T; Simmons, S; Laucht, A; Hudson, F E; Itoh, K M; Morello, A; Dzurak, A S

2015-10-15

Quantum computation requires qubits that can be coupled in a scalable manner, together with universal and high-fidelity one- and two-qubit logic gates. Many physical realizations of qubits exist, including single photons, trapped ions, superconducting circuits, single defects or atoms in diamond and silicon, and semiconductor quantum dots, with single-qubit fidelities that exceed the stringent thresholds required for fault-tolerant quantum computing. Despite this, high-fidelity two-qubit gates in the solid state that can be manufactured using standard lithographic techniques have so far been limited to superconducting qubits, owing to the difficulties of coupling qubits and dephasing in semiconductor systems. Here we present a two-qubit logic gate, which uses single spins in isotopically enriched silicon and is realized by performing single- and two-qubit operations in a quantum dot system using the exchange interaction, as envisaged in the Loss-DiVincenzo proposal. We realize CNOT gates via controlled-phase operations combined with single-qubit operations. Direct gate-voltage control provides single-qubit addressability, together with a switchable exchange interaction that is used in the two-qubit controlled-phase gate. By independently reading out both qubits, we measure clear anticorrelations in the two-spin probabilities of the CNOT gate.

Plastic behavior of two-phase intermetallic compounds based on L1{sub 2}-type (Al,Cr){sub 3}Ti

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, J.Y.; Wee, D.M.; Oh, M.H.

Plastic behavior of two-phase intermetallic compounds based on L1{sub 2}-type (Al,Cr){sub 3}Ti was investigated using compression test at R.T. and 77K. L1{sub 2} single phase alloys and two-phase alloys consisting of mainly L1{sub 2} phase and a few or 20% (mole percent) second phases were selected from Al-Ti-Cr phase diagram. In general, compared with L1{sub 2} single phase, two-phase alloys consisting of 20% second phase showed relatively high yield strength and poor ductility. Among the alloys, however, Al-21Ti-23Cr alloy consisting of 20% Cr{sub 2}Al phase showed available ductility as well as high yield strength. Plastic behavior of L1{sub 2} singlemore » phase alloys and two-phase alloys consisting of a few Cr{sub 2}Al was also investigated. Homogenization of arc melted ingots substantially reduced the amount of second phases but introduced extensive pore. When Cr content increased in L1{sub 2} single phase alloys after the homogenization, the volume fraction of pores in the alloys decreased, and no residual porosity was observed in two-phase alloys consisting of a few% Cr{sub 2}Al phase. Environmental effect on the ductility of the alloys was investigated using compression test at different strain rates (1.2 {times} 10{sup {minus}4}/s and 1.2 {times} 10{sup {minus}2}/s). Environmental embrittlement was least significant in Al-25Ti-10Cr alloy consisting of L1{sub 2} single phase among the alloys tested in this study. However, based on the combined estimation of the pore formation, environmental embrittlement and ingot cast structure, it could be supposed that Al-21Ti-23Cr alloy consisting of 20% Cr{sub 2}Al as a second phase is expected to show the best tensile elongation behavior among the materials tested.« less

A phasing and imputation method for pedigreed populations that results in a single-stage genomic evaluation

PubMed Central

2012-01-01

Background Efficient, robust, and accurate genotype imputation algorithms make large-scale application of genomic selection cost effective. An algorithm that imputes alleles or allele probabilities for all animals in the pedigree and for all genotyped single nucleotide polymorphisms (SNP) provides a framework to combine all pedigree, genomic, and phenotypic information into a single-stage genomic evaluation. Methods An algorithm was developed for imputation of genotypes in pedigreed populations that allows imputation for completely ungenotyped animals and for low-density genotyped animals, accommodates a wide variety of pedigree structures for genotyped animals, imputes unmapped SNP, and works for large datasets. The method involves simple phasing rules, long-range phasing and haplotype library imputation and segregation analysis. Results Imputation accuracy was high and computational cost was feasible for datasets with pedigrees of up to 25 000 animals. The resulting single-stage genomic evaluation increased the accuracy of estimated genomic breeding values compared to a scenario in which phenotypes on relatives that were not genotyped were ignored. Conclusions The developed imputation algorithm and software and the resulting single-stage genomic evaluation method provide powerful new ways to exploit imputation and to obtain more accurate genetic evaluations. PMID:22462519

Accurate single-shot quantitative phase imaging of biological specimens with telecentric digital holographic microscopy.

PubMed

Doblas, Ana; Sánchez-Ortiga, Emilio; Martínez-Corral, Manuel; Saavedra, Genaro; Garcia-Sucerquia, Jorge

2014-04-01

The advantages of using a telecentric imaging system in digital holographic microscopy (DHM) to study biological specimens are highlighted. To this end, the performances of nontelecentric DHM and telecentric DHM are evaluated from the quantitative phase imaging (QPI) point of view. The evaluated stability of the microscope allows single-shot QPI in DHM by using telecentric imaging systems. Quantitative phase maps of a section of the head of the drosophila melanogaster fly and of red blood cells are obtained via single-shot DHM with no numerical postprocessing. With these maps we show that the use of telecentric DHM provides larger field of view for a given magnification and permits more accurate QPI measurements with less number of computational operations.

Frequency guided methods for demodulation of a single fringe pattern.

PubMed

Wang, Haixia; Kemao, Qian

2009-08-17

Phase demodulation from a single fringe pattern is a challenging task but of interest. A frequency-guided regularized phase tracker and a frequency-guided sequential demodulation method with Levenberg-Marquardt optimization are proposed to demodulate a single fringe pattern. Demodulation path guided by the local frequency from the highest to the lowest is applied in both methods. Since critical points have low local frequency values, they are processed last so that the spurious sign problem caused by these points is avoided. These two methods can be considered as alternatives to the effective fringe follower regularized phase tracker. Demodulation results from one computer-simulated and two experimental fringe patterns using the proposed methods will be demonstrated. (c) 2009 Optical Society of America

Effect of Immersion Time on Corrosion Behavior of Single-Phase Alloy and Nanocomposite Bismuth Telluride-Based Thermoelectrics in NaCl Solution

NASA Astrophysics Data System (ADS)

Keshavarz, Mohsen K.; Fattah-Alhosseini, Arash

2018-05-01

The corrosiveness of bismuth telluride-based thermoelectric materials (n-type single-phase alloy and a nanocomposite with MoS2 nanoinclusions), in 0.1 molar solution of sodium chloride (NaCl), was investigated. The electrochemical impedance spectroscopy curves obtained after 1, 24, 48 and 72 h immersion time revealed the enhancement of the corrosion resistance of the nanocomposite specimen in a 0.1 molar NaCl solution in comparison with the single-phase bismuth telluride-based alloys, and the passivity increased by immersion time up to 72 h. The nanocomposite sample with submicron grains provided suitable nucleation sites for passive film nucleation that led to higher protective behavior.

Direct observation of phase-sensitive Hong-Ou-Mandel interference

NASA Astrophysics Data System (ADS)

Marek, Petr; Zapletal, Petr; Filip, Radim; Hashimoto, Yosuke; Toyama, Takeshi; Yoshikawa, Jun-ichi; Makino, Kenzo; Furusawa, Akira

2017-09-01

The quality of individual photons and their ability to interfere are traditionally tested by measuring the Hong-Ou-Mandel photon bunching effect. However, this phase-insensitive measurement only tests the particle aspect of the quantum interference, leaving out the phase-sensitive aspects relevant for continuous-variable processing. To overcome these limitations we formulate a witness capable of recognizing both the indistinguishability of the single photons and their quality with regard to their continuous-variable utilization. We exploit the conditional nonclassical squeezing and show that it can reveal both the particle and the wave aspects of the quantum interference in a single set of direct measurements. We experimentally test the witness by applying it to a pair of independent single photons retrieved on demand.

Preliminary experience and learning curve for laparoendoscopic single-site retroperitoneal pyeloplasty.

PubMed

Ou, Zhenyu; Qi, Lin; Yang, Jinrui; Chen, Xiang; Cao, Zhenzhen; Zu, Xiongbing; Liu, Longfei; Wang, Long

2013-09-01

To report our preliminary experience and to assess the learning curve for laparoendoscopic single-site retroperitoneal pyeloplasty (LESS-RP) for ureteropelvic junction obstruction (UPJO). From July 2010 to February 2012, LESS-RP was performed in 27 patients affected with UPJO by a single surgeon. A homemade single-access platform and both conventional and prebent instruments were applied. Patient characteristics and perioperative outcomes were analyzed. The cumulative sum (CUSUM) method was used to evaluate the learning curve. The LESS-RP was successfully accomplished in all 27 patients. The mean operative time (OT) was 175.9±22.5 minutes, and the mean estimated blood loss was 83.3±27.1 mL. We used the OT as a proxy to assess the learning curve. The CUSUM learning curve can be divided into two distinct phases: the initial 12 cases and the last 15 cases. There were significant differences in the mean OT (195.6 minutes versus 159.1 minutes, P<.001) and mean estimated blood loss (97.2 mL versus 72.2 mL, P=.014) between the two phases. The two phases did not differ in other parameters. LESS-RP is a safe and feasible procedure. The learning curve of a single surgeon suggests that the initial learning phase for LESS-RP can be completed after approximately 12 cases.

Polarized optical absorption and photoluminescence measurements in single-crystal thin films of 4'-dimethylamino-N-methyl-4-stilbazolium tosylate

NASA Astrophysics Data System (ADS)

Bhowmik, Achintya K.; Xu, Jianjun; Thakur, Mrinal

1999-11-01

Single-crystal thin films of the anhydrous (red) and the hydrated (orange) phases of the organic salt 4'-dimethylamino-N-methyl-4-stilbazolium tosylate were grown by a modification of the shear method. The optical absorption coefficients of the films were measured with light polarized along and normal to the dipole/molecular axis at both resonant and off-resonant wavelengths, and a strong dichroism was observed at the resonant wavelengths. The absorption measurements are important considering potential applications of these films (red phase) in high-speed single-pass thin-film electro-optic modulators [M. Thakur, J. Xu, A. Bhowmik, and L. Zhou, Appl. Phys. Lett. 74, 635 (1999)] and other photonic devices. Highly polarized photoluminescence (PL) has been observed in these films. The PL efficiencies of the red- and orange-phase single-crystal films were measured to be about 12% and 14%, respectively, which are significantly higher than the maximum PL efficiency measured in solution (3%).

Visual performance on detection tasks with double-targets of the same and different difficulty.

PubMed

Chan, Alan H S; Courtney, Alan J; Ma, C W

2002-10-20

This paper reports a study of measurement of horizontal visual sensitivity limits for 16 subjects in single-target and double-targets detection tasks. Two phases of tests were conducted in the double-targets task; targets of the same difficulty were tested in phase one while targets of different difficulty were tested in phase two. The range of sensitivity for the double-targets test was found to be smaller than that for single-target in both the same and different target difficulty cases. The presence of another target was found to affect performance to a marked degree. Interference effect of the difficult target on detection of the easy one was greater than that of the easy one on the detection of the difficult one. Performance decrement was noted when correct percentage detection was plotted against eccentricity of target in both the single-target and double-targets tests. Nevertheless, the non-significant correlation found between the performance for the two tasks demonstrated that it was impossible to predict quantitatively ability for detection of double targets from the data for single targets. This indicated probable problems in generalizing data for single target visual lobes to those for multiple targets. Also lobe area values obtained from measurements using a single-target task cannot be applied in a mathematical model for situations with multiple occurrences of targets.

CFD Analysis of different types of single basin solar stills

NASA Astrophysics Data System (ADS)

Maheswari, C. Uma; Meenakshi Reddy, R.

2018-03-01

The current work deals with the numerical and experimental analysis of a solar still of single basin with improved models of stepped, finned, PCM (Phase modification Materials) instrumentation in single slope. The work is additionally extended to double slope solar still of single basin and also the performances were compared with one another. The one slope basin inclinations were compared for 15° and 20°. From the investigations it had been ascertained that single slope with 20° and PCM instrumentation has given the upper productivity compared to different sorts.

Estimating Intervention Effects across Different Types of Single-Subject Experimental Designs: Empirical Illustration

ERIC Educational Resources Information Center

Moeyaert, Mariola; Ugille, Maaike; Ferron, John M.; Onghena, Patrick; Heyvaert, Mieke; Beretvas, S. Natasha; Van den Noortgate, Wim

2015-01-01

The purpose of this study is to illustrate the multilevel meta-analysis of results from single-subject experimental designs of different types, including AB phase designs, multiple-baseline designs, ABAB reversal designs, and alternating treatment designs. Current methodological work on the meta-analysis of single-subject experimental designs…

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sornadurai, D.; Ravindran, T. R.; Paul, V. Thomas

Synthesis parameters are optimized in order to grow single crystals of multiferroic BiFeO{sub 3}. 2 to 3 mm size pyramid (tetrahedron) shaped single crystals were successfully obtained by solvothermal method. Scanning electron microscopy with EDAX confirmed the phase formation. Raman scattering spectra of bulk BiFeO3 single crystals have been measured which match well with reported spectra.

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Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-09

... Single-Case Deviation from Competition Requirements: Transfer of Grantee Request for the Detroit Healthy... Health and Human Services (HHS). ACTION: Notice of Single-Case Deviation from Competition Requirements... pregnancy and interconceptional phases for women and infants residing in the proposed project area. In order...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holder, Aaron M.; Siol, Sebastian; Ndione, Paul F.

Structure and composition control the behavior of materials. Isostructural alloying is historically an extremely successful approach for tuning materials properties, but it is often limited by binodal and spinodal decomposition, which correspond to the thermodynamic solubility limit and the stability against composition fluctuations, respectively. We show that heterostructural alloys can exhibit a markedly increased range of metastable alloy compositions between the binodal and spinodal lines, thereby opening up a vast phase space for novel homogeneous single-phase alloys. We distinguish two types of heterostructural alloys, that is, those between commensurate and incommensurate phases. Because of the structural transition around the criticalmore » composition, the properties change in a highly nonlinear or even discontinuous fashion, providing a mechanism for materials design that does not exist in conventional isostructural alloys. The novel phase diagram behavior follows from standard alloy models using mixing enthalpies from first-principles calculations. Furthermore, thin-film deposition demonstrates the viability of the synthesis of these metastable single-phase domains and validates the computationally predicted phase separation mechanism above the upper temperature bound of the nonequilibrium single-phase region.« less

Translating landfill methane generation parameters among first-order decay models.

PubMed

Krause, Max J; Chickering, Giles W; Townsend, Timothy G

2016-11-01

Landfill gas (LFG) generation is predicted by a first-order decay (FOD) equation that incorporates two parameters: a methane generation potential (L 0 ) and a methane generation rate (k). Because non-hazardous waste landfills may accept many types of waste streams, multiphase models have been developed in an attempt to more accurately predict methane generation from heterogeneous waste streams. The ability of a single-phase FOD model to predict methane generation using weighted-average methane generation parameters and tonnages translated from multiphase models was assessed in two exercises. In the first exercise, waste composition from four Danish landfills represented by low-biodegradable waste streams was modeled in the Afvalzorg Multiphase Model and methane generation was compared to the single-phase Intergovernmental Panel on Climate Change (IPCC) Waste Model and LandGEM. In the second exercise, waste composition represented by IPCC waste components was modeled in the multiphase IPCC and compared to single-phase LandGEM and Australia's Solid Waste Calculator (SWC). In both cases, weight-averaging of methane generation parameters from waste composition data in single-phase models was effective in predicting cumulative methane generation from -7% to +6% of the multiphase models. The results underscore the understanding that multiphase models will not necessarily improve LFG generation prediction because the uncertainty of the method rests largely within the input parameters. A unique method of calculating the methane generation rate constant by mass of anaerobically degradable carbon was presented (k c ) and compared to existing methods, providing a better fit in 3 of 8 scenarios. Generally, single phase models with weighted-average inputs can accurately predict methane generation from multiple waste streams with varied characteristics; weighted averages should therefore be used instead of regional default values when comparing models. Translating multiphase first-order decay model input parameters by weighted average shows that single-phase models can predict cumulative methane generation within the level of uncertainty of many of the input parameters as defined by the Intergovernmental Panel on Climate Change (IPCC), which indicates that decreasing the uncertainty of the input parameters will make the model more accurate rather than adding multiple phases or input parameters.

Method for thermal processing alumina-enriched spinel single crystals

DOEpatents

Jantzen, Carol M.

1995-01-01

A process for age-hardening alumina-rich magnesium aluminum spinel to obtain the desired combination of characteristics of hardness, clarity, flexural strength and toughness comprises selection of the time-temperature pair for isothermal heating followed by quenching. The time-temperature pair is selected from the region wherein the precipitate groups have the characteristics sought. The single crystal spinel is isothermally heated and will, if heated long enough pass from its single phase through two pre-precipitates and two metastable precipitates to a stable secondary phase precipitate within the spinel matrix. Quenching is done slowly at first to avoid thermal shock, then rapidly.

Using dynamic interferometric synthetic aperature radar (InSAR) to image fast-moving surface waves

DOEpatents

Vincent, Paul

2005-06-28

A new differential technique and system for imaging dynamic (fast moving) surface waves using Dynamic Interferometric Synthetic Aperture Radar (InSAR) is introduced. This differential technique and system can sample the fast-moving surface displacement waves from a plurality of moving platform positions in either a repeat-pass single-antenna or a single-pass mode having a single-antenna dual-phase receiver or having dual physically separate antennas, and reconstruct a plurality of phase differentials from a plurality of platform positions to produce a series of desired interferometric images of the fast moving waves.

Optical Parametric Amplification of Single Photon: Statistical Properties and Quantum Interference

NASA Astrophysics Data System (ADS)

Xu, Xue-Xiang; Yuan, Hong-Chun

2014-05-01

By using phase space method, we theoretically investigate the quantum statistical properties and quantum interference of optical parametric amplification of single photon. The statistical properties, such as the Wigner function (WF), average photon number, photon number distribution and parity, are derived analytically for the fields of the two output ports. The results indicate that the fields in the output ports are multiphoton states rather than single photon state due to the amplification of the optical parametric amplifiers (OPA). In addition, the phase sensitivity is also examined by using the detection scheme of parity measurement.

Coulomb blockade in a single tunnel junction directly connected to a multiwalled carbon nanotube

NASA Astrophysics Data System (ADS)

Haruyama, Junji; Takesue, Izumi; Sato, Yuki

2000-10-01

We report on Coulomb blockade in a single tunnel junction directly connected to a multiwalled carbon nanotube (MWNT) by utilizing a nanoporous alumina film. The MWNT exhibits a weak localization effect with strong spin flip scattering. Experimental results and analysis suggest that a high-impedance external environment caused by the weak localization in the MWNT can yield Coulomb blockade, in accordance with phase correlation theory in a single junction system. It is also revealed that the Coulomb blockade is very sensitive to phase modulation in the MWNT, which also acts as a high-impedance transmission line.

Optimal dual-fuel propulsion for minimum inert weight or minimum fuel cost

NASA Technical Reports Server (NTRS)

Martin, J. A.

1973-01-01

An analytical investigation of single-stage vehicles with multiple propulsion phases has been conducted with the phasing optimized to minimize a general cost function. Some results are presented for linearized sizing relationships which indicate that single-stage-to-orbit, dual-fuel rocket vehicles can have lower inert weight than similar single-fuel rocket vehicles and that the advantage of dual-fuel vehicles can be increased if a dual-fuel engine is developed. The results also indicate that the optimum split can vary considerably with the choice of cost function to be minimized.

Selective conversion of {Mo132} Keplerate ion into 4-electron reduced crown-capped Keggin derivative [Te5Mo15O57](8-). A key intermediate to single-phase M1 multielement MoVTeO light-alkanes oxidation catalyst.

PubMed

Canioni, Romain; Marchal-Roch, Catherine; Leclerc-Laronze, Nathalie; Haouas, Mohamed; Taulèlle, Francis; Marrot, Jérôme; Paul, Sebastien; Lamonier, Carole; Paul, Jean-François; Loridant, Stéphane; Millet, Jean-Marc M; Cadot, Emmanuel

2011-06-14

{Mo(132)} Keplerate anion reacts with tellurites to give a soluble precursor to produce in hydrothermal conditions single-phase M1 MoVTeO light-alkanes oxidation catalyst. Characterization of this Te-containing intermediate by single-crystal X-ray diffraction, (125)Te NMR, UV-visible and redox titration reveals a molybdotellurite anion as a crown-capped Keggin derivative. This journal is © The Royal Society of Chemistry 2011

Fully tunable 360° microwave photonic phase shifter based on a single semiconductor optical amplifier.

PubMed

Sancho, Juan; Lloret, Juan; Gasulla, Ivana; Sales, Salvador; Capmany, José

2011-08-29

A fully tunable microwave photonic phase shifter involving a single semiconductor optical amplifier (SOA) is proposed and demonstrated. 360° microwave phase shift has been achieved by tuning the carrier wavelength and the optical input power injected in an SOA while properly profiting from the dispersion feature of a conveniently designed notch filter. It is shown that the optical filter can be advantageously employed to switch between positive and negative microwave phase shifts. Numerical calculations corroborate the experimental results showing an excellent agreement.

Berry phase of primordial scalar and tensor perturbations in single-field inflationary models

NASA Astrophysics Data System (ADS)

Balajany, Hamideh; Mehrafarin, Mohammad

2018-06-01

In the framework of the single-field slow-roll inflation, we derive the Hamiltonian of the linear primordial scalar and tensor perturbations in the form of time-dependent harmonic oscillator Hamiltonians. We find the invariant operators of the resulting Hamiltonians and use their eigenstates to calculate the adiabatic Berry phase for sub-horizon modes in terms of the Lewis-Riesenfeld phase. We conclude by discussing the discrepancy in the results of Pal et al. (2013) [21] for these Berry phases, which is resolved to yield agreement with our results.

The dressed atom as binary phase modulator: towards attojoule/edge optical phase-shift keying.

PubMed

Kerckhoff, Joseph; Armen, Michael A; Pavlichin, Dmitri S; Mabuchi, Hideo

2011-03-28

We use a single 133Cs atom strongly coupled to an optical resonator to induce random binary phase modulation of a near infra-red, ∼ 500 pW laser beam, with each modulation edge caused by the dissipation of a single photon (≈ 0.23 aJ) by the atom. While our ability to deterministically induce phase edges with an additional optical control beam is limited thus far, theoretical analysis of an analogous, solid-state system indicates that efficient external control should be achievable in demonstrated nanophotonic systems.

Optically phase-locked electronic speckle pattern interferometer system performance for vibration measurement in random displacement fields

NASA Astrophysics Data System (ADS)

Moran, Steve E.; Lugannani, Robert; Craig, Peter N.; Law, Robert L.

1989-02-01

An analysis is made of the performance of an optically phase-locked electronic speckle pattern interferometer in the presence of random noise displacements. Expressions for the phase-locked speckle contrast for single-frame imagery and the composite rms exposure for two sequentially subtracted frames are obtained in terms of the phase-locked composite and single-frame fringe functions. The noise fringe functions are evaluated for stationary, coherence-separable noise displacements obeying Gauss-Markov temporal statistics. The theoretical findings presented here are qualitatively supported by experimental results.

Phase recovery from a single interferogram with closed fringes by phase unwrapping

DOE Office of Scientific and Technical Information (OSTI.GOV)

Munoz-Maciel, Jesus; Casillas-Rodriguez, Francisco J.; Mora-Gonzalez, Miguel

2011-01-01

We describe a new algorithm for phase determination from a single interferogram with closed fringes based on an unwrapping procedure. Here we use bandpass filtering in the Fourier domain, obtaining two wrapped phases with sign changes corresponding to the orientation of the applied filters. An unwrapping scheme that corrects the sign ambiguities by comparing the local derivatives is then proposed. This can be done, assuming that the phase derivatives do not change abruptly among adjacent areas as occurs with smooth continuous phase maps. The proposed algorithm works fast and is robust against noise, as demonstrated in experimental and simulated data.

Physical properties of V 1-xTi xO₂ (0 < x < 0.187) single crystals

DOE PAGES

Kong, Tai; Masters, Morgan W.; Bud’ko, Sergey L.; ...

2015-02-13

Free standing, low strain, single crystals of pure and titanium doped VO₂ were grown out of an excess of V ₂O₅ using high temperature solution growth techniques. At T MI ~ 340 K, pure VO₂ exhibits a clear first-order phase transition from a high-temperature paramagnetic tetragonal phase (R) to a low-temperature non-magnetic monoclinic phase (M1). With Ti doping, another monoclinic phase (M2) emerges between the R and M1 phases. The phase transition temperature between R and M2 increases with increasing Ti doping while the transition temperature between M2 and M1 decreases.

Porous single-phase NiTi processed under Ca reducing vapor for use as a bone graft substitute.

PubMed

Bertheville, Bernard

2006-03-01

Porous nickel-titanium alloys (NiTi, nitinol) have recently attracted attention in clinical surgery because they are a very interesting alternative to the more brittle and less machinable conventional porous Ca-based ceramics. The main remaining limitations come from the chemical homogeneity of the as-processed porous nickel-titanium alloys, which always contain undesired secondary Ti- and Ni-rich phases. These are known to weaken the NiTi products, to favor their cavitation corrosion and to decrease their biocompatibility. Elemental nickel must also be avoided because it could give rise to several adverse tissue reactions. Therefore, the synthesis of porous single-phase NiTi alloys by using a basic single-step sintering procedure is an important step towards the processing of safe implant materials. The sintering process used in this work is based on a vapor phase calciothermic reduction operating during the NiTi compound formation. The as-processed porous nickel-titanium microstructure is single-phase and shows a uniformly open pore distribution with porosity of about 53% and pore diameters in the range 20-100 microm. Furthermore, due to the process, fine CaO layers grow on the NiTi outer and inner surfaces, acting as possible promoting agents for the ingrowth of bone cells at the implantation site.

Fiber Grating Coupled Light Source Capable of Tunable, Single Frequency Operation

NASA Technical Reports Server (NTRS)

Krainak, Michael A. (Inventor); Duerksen, Gary L. (Inventor)

2001-01-01

Fiber Bragg grating coupled light sources can achieve tunable single-frequency (single axial and lateral spatial mode) operation by correcting for a quadratic phase variation in the lateral dimension using an aperture stop. The output of a quasi-monochromatic light source such as a Fabry Perot laser diode is astigmatic. As a consequence of the astigmatism, coupling geometries that accommodate the transverse numerical aperture of the laser are defocused in the lateral dimension, even for apsherical optics. The mismatch produces the quadratic phase variation in the feedback along the lateral axis at the facet of the laser that excites lateral modes of higher order than the TM(sub 00). Because the instability entails excitation of higher order lateral submodes, single frequency operation also is accomplished by using fiber Bragg gratings whose bandwidth is narrower than the submode spacing. This technique is particularly pertinent to the use of lensed fiber gratings in lieu of discrete coupling optics. Stable device operation requires overall phase match between the fed-back signal and the laser output. The fiber Bragg grating acts as a phase-preserving mirror when the Bragg condition is met precisely. The phase-match condition is maintained throughout the fiber tuning range by matching the Fabry-Perot axial mode wavelength to the passband center wavelength of the Bragg grating.

Analytical results for a conditional phase shift between single-photon pulses in a nonlocal nonlinear medium

NASA Astrophysics Data System (ADS)

Viswanathan, Balakrishnan; Gea-Banacloche, Julio

2018-03-01

It has been suggested that second-order nonlinearities could be used for quantum logic at the single-photon level. Specifically, successive two-photon processes in principle could accomplish the phase shift (conditioned on the presence of two photons in the low-frequency modes) |011 〉→i |100 〉→-|011 〉 . We have analyzed a recent scheme proposed by Xia et al. [Phys. Rev. Lett. 116, 023601 (2016)], 10.1103/PhysRevLett.116.023601 to induce such a conditional phase shift between two single-photon pulses propagating at different speeds through a nonlinear medium with a nonlocal response. We present here an analytical solution for the most general case, i.e., for an arbitrary response function, initial state, and pulse velocity, which supports their numerical observation that a π phase shift with unit fidelity is possible, in principle, in an appropriate limit. We also discuss why this is possible in this system, despite the theoretical objections to the possibility of conditional phase shifts on single photons that were raised some time ago by Shapiro [Phys. Rev. A 73, 062305 (2006)], 10.1103/PhysRevA.73.062305 and by Gea-Banacloche [Phys. Rev. A 81, 043823 (2010)], 10.1103/PhysRevA.81.043823 one of us.

Fuel Injector: Air swirl characterization aerothermal modeling, phase 2, volume 2

NASA Technical Reports Server (NTRS)

Nikjooy, M.; Mongia, H. C.; Mcdonell, V. G.; Samuelson, G. S.

1993-01-01

A well integrated experimental/analytical investigation was conducted to provide benchmark quality data relevant to prefilming type airblast fuel nozzle and its interaction with combustor dome air swirler. The experimental investigation included a systematic study of both single-phase flows that involved single and twin co-axial jets with and without swirl. A two-component Phase Doppler Particle Analyzer (PDPA) equipment was used to document the interaction of single and co-axial air jets with glass beads that simulate nonevaporating spray and simultaneously avoid the complexities associated with fuel atomization processes and attendant issues about the specification of relevant boundary conditions. The interaction of jets with methanol spray produced by practical airblast nozzle was also documented in the spatial domain of practical interest. Model assessment activities included the use of three turbulence models (k-epsilon, algebraic second moment (ASM) and differential second moment (DSM)) for the carrier phase, deterministic or stochastic Lagrangian treatment of the dispersed phase, and advanced numerical schemes. Although qualitatively good comparison with data was obtained for most of the cases investigated, the model deficiencies in regard to modeled dissipation rate transport equation, single length scale, pressure-strain correlation, and other critical closure issues need to be resolved before one can achieve the degree of accuracy required to analytically design combustion systems.

Fuel injector: Air swirl characterization aerothermal modeling, phase 2, volume 1

NASA Technical Reports Server (NTRS)

Nikjooy, M.; Mongia, H. C.; Mcdonell, V. G.; Samuelsen, G. S.

1993-01-01

A well integrated experimental/analytical investigation was conducted to provide benchmark quality relevant to a prefilming type airblast fuel nozzle and its interaction with the combustor dome air swirler. The experimental investigation included a systematic study of both single-phase flows that involved single and twin co-axial jets with and without swirl. A two-component Phase Doppler Particle Analyzer (PDPA) was used to document the interaction of single and co-axial air jets with glass beads that simulate nonevaporating spray and simultaneously avoid the complexities associated with fuel atomization processes and attendant issues about the specification of relevant boundary conditions. The interaction of jets with methanol spray produced by practical airblast nozzle was also documented in the spatial domain of practical interest. Model assessment activities included the use of three turbulence models (k-epsilon, algebraic second moment (ASM), and differential second moment (DSM)) for the carrier phase, deterministic or stochastic Lagrangian treatment of the dispersed phase, and advanced numerical schemes. Although qualitatively good comparison with data was obtained for most of the cases investigated, the model deficiencies in regard to modeled dissipation rate transport equation, single length scale, pressure-strain correlation, and other critical closure issues need to be resolved before one can achieve the degree of accuracy required to analytically design combustion systems.

Preliminary Experiments with a Unified Controller for a Powered Knee-Ankle Prosthetic Leg Across Walking Speeds

PubMed Central

Villarreal, Dario J.; Gregg, Robert D.

2016-01-01

This paper presents the experimental validation of a novel control strategy that unifies the entire gait cycle of a powered knee-ankle prosthetic leg without the need to switch between controllers for different periods of gait. Current control methods divide the gait cycle into several sequential periods each with independent controllers, resulting in many patient-specific control parameters and switching rules that must be tuned for a specific walking speed. The single controller presented is speed-invariant with a minimal number of control parameters to be tuned. A single, periodic virtual constraint is derived that exactly characterizes the desired actuated joint motion as a function of a mechanical phase variable across walking cycles. A single sensor was used to compute a phase variable related to the residual thigh angle’s phase plane, which was recently shown to robustly represent the phase of non-steady human gait. This phase variable allows the prosthesis to synchronize naturally with the human user for intuitive, biomimetic behavior. A custom powered knee-ankle prosthesis was designed and built to implement the control strategy and validate its performance. A human subject experiment was conducted across multiple walking speeds (1 to 3 miles/hour) in a continuous sequence with the single phase-based controller, demonstrating its adaptability to the user’s intended speed. PMID:28392969

Three-dimensional single-cell imaging with X-ray waveguides in the holographic regime

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krenkel, Martin; Toepperwien, Mareike; Alves, Frauke

X-ray tomography at the level of single biological cells is possible in a low-dose regime, based on full-field holographic recordings, with phase contrast originating from free-space wave propagation. Building upon recent progress in cellular imaging based on the illumination by quasi-point sources provided by X-ray waveguides, here this approach is extended in several ways. First, the phase-retrieval algorithms are extended by an optimized deterministic inversion, based on a multi-distance recording. Second, different advanced forms of iterative phase retrieval are used, operational for single-distance and multi-distance recordings. Results are compared for several different preparations of macrophage cells, for different staining andmore » labelling. As a result, it is shown that phase retrieval is no longer a bottleneck for holographic imaging of cells, and how advanced schemes can be implemented to cope also with high noise and inconsistencies in the data.« less

Three-dimensional single-cell imaging with X-ray waveguides in the holographic regime

DOE PAGES

Krenkel, Martin; Toepperwien, Mareike; Alves, Frauke; ...

2017-06-29

X-ray tomography at the level of single biological cells is possible in a low-dose regime, based on full-field holographic recordings, with phase contrast originating from free-space wave propagation. Building upon recent progress in cellular imaging based on the illumination by quasi-point sources provided by X-ray waveguides, here this approach is extended in several ways. First, the phase-retrieval algorithms are extended by an optimized deterministic inversion, based on a multi-distance recording. Second, different advanced forms of iterative phase retrieval are used, operational for single-distance and multi-distance recordings. Results are compared for several different preparations of macrophage cells, for different staining andmore » labelling. As a result, it is shown that phase retrieval is no longer a bottleneck for holographic imaging of cells, and how advanced schemes can be implemented to cope also with high noise and inconsistencies in the data.« less

Photon-counting-based diffraction phase microscopy combined with single-pixel imaging

NASA Astrophysics Data System (ADS)

Shibuya, Kyuki; Araki, Hiroyuki; Iwata, Tetsuo

2018-04-01

We propose a photon-counting (PC)-based quantitative-phase imaging (QPI) method for use in diffraction phase microscopy (DPM) that is combined with a single-pixel imaging (SPI) scheme (PC-SPI-DPM). This combination of DPM with the SPI scheme overcomes a low optical throughput problem that has occasionally prevented us from obtaining quantitative-phase images in DPM through use of a high-sensitivity single-channel photodetector such as a photomultiplier tube (PMT). The introduction of a PMT allowed us to perform PC with ease and thus solved a dynamic range problem that was inherent to SPI. As a proof-of-principle experiment, we performed a comparison study of analogue-based SPI-DPM and PC-SPI-DPM for a 125-nm-thick indium tin oxide (ITO) layer coated on a silica glass substrate. We discuss the basic performance of the method and potential future modifications of the proposed system.

Phase-and-amplitude recovery from a single phase-contrast image using partially spatially coherent x-ray radiation

NASA Astrophysics Data System (ADS)

Beltran, Mario A.; Paganin, David M.; Pelliccia, Daniele

2018-05-01

A simple method of phase-and-amplitude extraction is derived that corrects for image blurring induced by partially spatially coherent incident illumination using only a single intensity image as input. The method is based on Fresnel diffraction theory for the case of high Fresnel number, merged with the space-frequency description formalism used to quantify partially coherent fields and assumes the object under study is composed of a single-material. A priori knowledge of the object’s complex refractive index and information obtained by characterizing the spatial coherence of the source is required. The algorithm was applied to propagation-based phase-contrast data measured with a laboratory-based micro-focus x-ray source. The blurring due to the finite spatial extent of the source is embedded within the algorithm as a simple correction term to the so-called Paganin algorithm and is also numerically stable in the presence of noise.

Dissociation between sustained single-neuron spiking and transient β-LFP oscillations in primate motor cortex

PubMed Central

Rule, Michael E.; Vargas-Irwin, Carlos E.; Donoghue, John P.

2017-01-01

Determining the relationship between single-neuron spiking and transient (20 Hz) β-local field potential (β-LFP) oscillations is an important step for understanding the role of these oscillations in motor cortex. We show that whereas motor cortex firing rates and beta spiking rhythmicity remain sustained during steady-state movement preparation periods, β-LFP oscillations emerge, in contrast, as short transient events. Single-neuron mean firing rates within and outside transient β-LFP events showed no differences, and no consistent correlation was found between the beta oscillation amplitude and firing rates, as was the case for movement- and visual cue-related β-LFP suppression. Importantly, well-isolated single units featuring beta-rhythmic spiking (43%, 125/292) showed no apparent or only weak phase coupling with the transient β-LFP oscillations. Similar results were obtained for the population spiking. These findings were common in triple microelectrode array recordings from primary motor (M1), ventral (PMv), and dorsal premotor (PMd) cortices in nonhuman primates during movement preparation. Although beta spiking rhythmicity indicates strong membrane potential fluctuations in the beta band, it does not imply strong phase coupling with β-LFP oscillations. The observed dissociation points to two different sources of variation in motor cortex β-LFPs: one that impacts single-neuron spiking dynamics and another related to the generation of mesoscopic β-LFP signals. Furthermore, our findings indicate that rhythmic spiking and diverse neuronal firing rates, which encode planned actions during movement preparation, may naturally limit the ability of different neuronal populations to strongly phase-couple to a single dominant oscillation frequency, leading to the observed spiking and β-LFP dissociation. NEW & NOTEWORTHY We show that whereas motor cortex spiking rates and beta (~20 Hz) spiking rhythmicity remain sustained during steady-state movement preparation periods, β-local field potential (β-LFP) oscillations emerge, in contrast, as transient events. Furthermore, the β-LFP phase at which neurons spike drifts: phase coupling is typically weak or absent. This dissociation points to two sources of variation in the level of motor cortex beta: one that impacts single-neuron spiking and another related to the generation of measured mesoscopic β-LFPs. PMID:28100654

Single-shot measurement of phase and amplitude by using a heterodyne time-lens system and ultrafast digital time-holography

NASA Astrophysics Data System (ADS)

Tikan, Alexey; Bielawski, Serge; Szwaj, Christophe; Randoux, Stéphane; Suret, Pierre

2018-04-01

Temporal imaging systems are outstanding tools for single-shot observation of optical signals that have irregular and ultrafast dynamics. They allow long time windows to be recorded with femtosecond resolution, and do not rely on complex algorithms. However, simultaneous recording of amplitude and phase remains an open challenge for these systems. Here, we present a new heterodyne time-lens arrangement that efficiently records both the amplitude and phase of complex and random signals over large temporal windows (tens of picoseconds). Phase and time are encoded onto the two spatial dimensions of a camera. We implement this phase-sensitive time-lens system in two configurations: a time microscope and a digital temporal-holography device that enables single-shot measurement with a temporal resolution of 80 fs. We demonstrate direct application of our heterodyne time-lens to turbulent-like optical fields and optical rogue waves generated from nonlinear propagation of partially coherent waves inside optical fibres.

Molecular Beam Epitaxy of lithium niobium oxide multifunctional materials

NASA Astrophysics Data System (ADS)

Tellekamp, M. Brooks; Shank, Joshua C.; Doolittle, W. Alan

2017-04-01

The role of stoichiometry and growth temperature in the preferential nucleation of material phases in the Li-Nb-O family are explored yielding an empirical growth phase diagram. It is shown that while single parameter variation often produces multi-phase films, combining substrate temperature control with the previously published lithium flux limited growth allows the repeatable growth of high quality single crystalline films of many different oxide phases. Higher temperatures (800-1050 °C) than normally used in MBE were necessary to achieve high quality materials. At these temperatures the desorption of surface species is shown to play an important role in film composition. Using this method single phase films of NbO, NbO2, LiNbO2, Li3NbO4, LiNbO3, and LiNb3O8 have been achieved in the same growth system, all on c-plane sapphire. Finally, the future of these films in functional oxide heterostructures is briefly discussed.

Mechanism of Radiation Damage Reduction in Equiatomic Multicomponent Single Phase Alloys.

PubMed

Granberg, F; Nordlund, K; Ullah, Mohammad W; Jin, K; Lu, C; Bei, H; Wang, L M; Djurabekova, F; Weber, W J; Zhang, Y

2016-04-01

Recently a new class of metal alloys, of single-phase multicomponent composition at roughly equal atomic concentrations ("equiatomic"), have been shown to exhibit promising mechanical, magnetic, and corrosion resistance properties, in particular, at high temperatures. These features make them potential candidates for components of next-generation nuclear reactors and other high-radiation environments that will involve high temperatures combined with corrosive environments and extreme radiation exposure. In spite of a wide range of recent studies of many important properties of these alloys, their radiation tolerance at high doses remains unexplored. In this work, a combination of experimental and modeling efforts reveals a substantial reduction of damage accumulation under prolonged irradiation in single-phase NiFe and NiCoCr alloys compared to elemental Ni. This effect is explained by reduced dislocation mobility, which leads to slower growth of large dislocation structures. Moreover, there is no observable phase separation, ordering, or amorphization, pointing to a high phase stability of this class of alloys.

Mechanism of Radiation Damage Reduction in Equiatomic Multicomponent Single Phase Alloys

NASA Astrophysics Data System (ADS)

Granberg, F.; Nordlund, K.; Ullah, Mohammad W.; Jin, K.; Lu, C.; Bei, H.; Wang, L. M.; Djurabekova, F.; Weber, W. J.; Zhang, Y.

2016-04-01

Recently a new class of metal alloys, of single-phase multicomponent composition at roughly equal atomic concentrations ("equiatomic"), have been shown to exhibit promising mechanical, magnetic, and corrosion resistance properties, in particular, at high temperatures. These features make them potential candidates for components of next-generation nuclear reactors and other high-radiation environments that will involve high temperatures combined with corrosive environments and extreme radiation exposure. In spite of a wide range of recent studies of many important properties of these alloys, their radiation tolerance at high doses remains unexplored. In this work, a combination of experimental and modeling efforts reveals a substantial reduction of damage accumulation under prolonged irradiation in single-phase NiFe and NiCoCr alloys compared to elemental Ni. This effect is explained by reduced dislocation mobility, which leads to slower growth of large dislocation structures. Moreover, there is no observable phase separation, ordering, or amorphization, pointing to a high phase stability of this class of alloys.

Femtosecond-pulse inscription of fiber Bragg gratings with single or multiple phase-shifts in the structure

NASA Astrophysics Data System (ADS)

Wolf, Alexey; Dostovalov, Alexandr; Skvortsov, Mikhail; Raspopin, Kirill; Parygin, Alexandr; Babin, Sergey

2018-05-01

In this work, long high-quality fiber Bragg gratings with phase shifts in the structure are inscribed directly in the optical fiber by point-by-point technique using femtosecond laser pulses. Phase shifts are introduced during the inscription process with a piezoelectric actuator, which rapidly shifts the fiber along the direction of its movement in a chosen point of the grating with a chosen shift value. As examples, single and double π phase shifts are introduced in fiber Bragg gratings with a length up to 34 mm in passive fibers, which provide corresponding transmission peaks with bandwidth less than 1 pm. It is shown that 37 mm π -phase-shifted grating inscribed in an active Er-doped fiber forms high-quality DFB laser cavity generating single-frequency radiation at 1550 nm with bandwidth of 20 kHz and signal-to-noise ratio of >70 dB. The inscription technique has a high degree of performance and flexibility and can be easily implemented in fibers of various types.

Single-exposure quantitative phase imaging in color-coded LED microscopy.

PubMed

Lee, Wonchan; Jung, Daeseong; Ryu, Suho; Joo, Chulmin

2017-04-03

We demonstrate single-shot quantitative phase imaging (QPI) in a platform of color-coded LED microscopy (cLEDscope). The light source in a conventional microscope is replaced by a circular LED pattern that is trisected into subregions with equal area, assigned to red, green, and blue colors. Image acquisition with a color image sensor and subsequent computation based on weak object transfer functions allow for the QPI of a transparent specimen. We also provide a correction method for color-leakage, which may be encountered in implementing our method with consumer-grade LEDs and image sensors. Most commercially available LEDs and image sensors do not provide spectrally isolated emissions and pixel responses, generating significant error in phase estimation in our method. We describe the correction scheme for this color-leakage issue, and demonstrate improved phase measurement accuracy. The computational model and single-exposure QPI capability of our method are presented by showing images of calibrated phase samples and cellular specimens.

Mechanism of Radiation Damage Reduction in Equiatomic Multicomponent Single Phase Alloys

DOE PAGES

Granberg, F.; Nordlund, K.; Ullah, Mohammad W.; ...

2016-04-01

Recently a new class of metal alloys, of single-phase multicomponent composition at roughly equal atomic concentrations (“equiatomic”), have been shown to exhibit promising mechanical, magnetic, and corrosion resistance properties, in particular, at high temperatures. These features make them potential candidates for components of next-generation nuclear reactors and other high-radiation environments that will involve high temperatures combined with corrosive environments and extreme radiation exposure. In spite of a wide range of recent studies of many important properties of these alloys, their radiation tolerance at high doses remains unexplored. In this work, a combination of experimental and modeling efforts reveals a substantialmore » reduction of damage accumulation under prolonged irradiation in single-phase NiFe and NiCoCr alloys compared to elemental Ni. This effect is explained by reduced dislocation mobility, which leads to slower growth of large dislocation structures. Finally and moreover, there is no observable phase separation, ordering, or amorphization, pointing to a high phase stability of this class of alloys.« less

Combining nonoverlap and trend for single-case research: Tau-U.

PubMed

Parker, Richard I; Vannest, Kimberly J; Davis, John L; Sauber, Stephanie B

2011-06-01

A new index for analysis of single-case research data was proposed, Tau-U, which combines nonoverlap between phases with trend from within the intervention phase. In addition, it provides the option of controlling undesirable Phase A trend. The derivation of Tau-U from Kendall's Rank Correlation and the Mann-Whitney U test between groups is demonstrated. The equivalence of trend and nonoverlap is also shown, with supportive citations from field leaders. Tau-U calculations are demonstrated for simple AB and ABA designs. Tau-U is then field tested on a sample of 382 published data series. Controlling undesirable Phase A trend caused only a modest change from nonoverlap. The inclusion of Phase B trend yielded more modest results than simple nonoverlap. The Tau-U score distribution did not show the artificial ceiling shown by all other nonoverlap techniques. It performed reasonably well with autocorrelated data. Tau-U shows promise for single-case applications, but further study is desirable. Copyright © 2011. Published by Elsevier Ltd.

Forest resources of southeast Alaska, 2000: results of a single-phase systematic sample.

Treesearch

Willem W.S. van Hees

2003-01-01

A baseline assessment of forest resources in southeast Alaska was made by using a single-phase, unstratified, systematic-grid sample, with ground plots established at each grid intersection. Ratio-of-means estimators were used to develop population estimates. Forests cover an estimated 48 percent of the 22.9-million-acre southeast Alaska inventory unit. Dominant forest...

Phase transition between quantum and classical regimes for the escape rate of dimeric molecular nanomagnets in a staggered magnetic field

NASA Astrophysics Data System (ADS)

Owerre, S. A.; Paranjape, M. B.

2014-04-01

We study the phase transition of the escape rate of exchange-coupled dimer of single-molecule magnets which are coupled either ferromagnetically or antiferromagnetically in a staggered magnetic field and an easy z-axis anisotropy. The Hamiltonian for this system has been used to study dimeric molecular nanomagnet [Mn4]2 which is comprised of two single molecule magnets coupled antiferromagnetically. We generalize the method of mapping a single-molecule magnetic spin problem onto a quantum-mechanical particle to dimeric molecular nanomagnets. The problem is mapped to a single particle quantum-mechanical Hamiltonian in terms of the relative coordinate and a coordinate dependent reduced mass. It is shown that the presence of the external staggered magnetic field creates a phase boundary separating the first- from the second-order transition. With the set of parameters used by R. Tiron et al. (2003) [25] and S. Hill et al. (2003) [20] to fit experimental data for [Mn4]2 dimer we find that the critical temperature at the phase boundary is T0(c)=0.29K. Therefore, thermally activated transitions should occur for temperatures greater than T0(c).

Electron interactions, spin-orbit coupling, intersite correlations in pyrochlore iridates: a comparison of single-site and cluster calculations

NASA Astrophysics Data System (ADS)

Wang, Runzhi; Go, Ara; Millis, Andrew

Pyrochlore iridates (R2 Ir2O7) are studied using density functional theory plus single-site and cluster dynamical mean-field theory (DFT+DMFT). The calculations include spin-orbit coupling. Significant differences between the single-site and cluster calculations are found. The single-site approximation fails to account for the properties of the paramagnetic insulator phase, in particular predicting a larger gap than found in experiments, while cluster calculations yield gaps consistent with transport data. A ground-state phase diagram is computed. Paramagnetic metal, metallic all-in/all-out (AIAO) and insulating AIAO phases are found. Tilted Weyl cones are observed in the AIAO metallic phase for a relatively wide range of interaction strength. Our paramagnetic calculations predict almost identical behaviors for the Y and Eu compound, conflicting with the strong material dependence reported in experiments. Inclusion of magnetic order restores the material difference. The physical origin of the difference is discussed. The results indicate that intersite effects, most likely of antiferromagnetic origin, play an important role in studying the physics of pyrochlore iridates. This work is supported by DOE-ER046169.

Crystallography of the NiHfSi Phase in a NiAl (0.5 Hf) Single-Crystal Alloy

NASA Technical Reports Server (NTRS)

Garg, A.; Noebe, R. D.; Darolia, R.

1996-01-01

Small additions of Hf to conventionally processed NiAl single crystals result in the precipitation of a high density of cuboidal G-phase along with a newly identified silicide phase. Both of these phases form in the presence of Si which is not an intentional alloying addition but is a contaminant resulting from contact with the ceramic shell molds during directional solidification of the single-crystal ingots. The morphology, crystal structure and Orientation Relationship (OR) of the silicide phase in a NiAl (0.5 at.%Hf) single-crystal alloy have been determined using transmission electron microscopy, electron microdiffraction and energy dispersive X-ray spectroscopy. Qualitative elemental analysis and indexing of the electron microdiffraction patterns from the new phase indicate that it is an orthorhombic NiHfSi phase with unit cell parameters, a = 0.639 nm, b = 0.389 nm and c = 0.72 nm, and space group Pnma. The NiHfSi phase forms as thin rectangular plates on NiAl/111/ planes with an OR that is given by NiHfSi(100))(parallel) NiAl(111) and NiHfSi zone axes(010) (parallel) NiAl zone axes (101). Twelve variants of the NiHfSi phase were observed in the alloy and the number of variants and rectangular morphology of NiHfSi plates are consistent with symmetry requirements. Quenching experiments indicate that nucleation of the NiHfSi phase in NiAI(Hf) alloys is aided by the formation of NiAl group of zone axes (111) vacancy loops that form on the NiAl /111/ planes.

Preparative crystallization of a single chain antibody using an aqueous two-phase system.

PubMed

Huettmann, Hauke; Berkemeyer, Matthias; Buchinger, Wolfgang; Jungbauer, Alois

2014-11-01

A simultaneous crystallization and aqueous two-phase extraction of a single chain antibody was developed, demonstrating process integration. The process conditions were designed to form an aqueous two-phase system, and to favor crystallization, using sodium sulfate and PEG-2000. At sufficiently high concentrations of PEG, a second phase was generated in which the protein crystallization occurred simultaneously. The single chain antibody crystals were partitioned to the top, polyethylene glycol-rich phase. The crystal nucleation took place in the sodium sulfate-rich phase and at the phase boundary, whereas crystal growth was progressing mainly in the polyethylene glycol-rich phase. The crystals in the polyethylene glycol-rich phase grew to a size of >50 µm. Additionally, polyethylene glycol acted as an anti-solvent, thus, it influenced the crystallization yield. A phase diagram with an undersaturation zone, crystallization area, and amorphous precipitation zone was established. Only small differences in polyethylene glycol concentration caused significant shifts of the crystallization yield. An increase of the polyethylene glycol content from 2% (w/v) to 4% (w/v) increased the yield from approximately 63-87%, respectively. Our results show that crystallization in aqueous two-phase systems is an opportunity to foster process integration. © 2014 Wiley Periodicals, Inc.

Perovskite single crystals and thin films for optoelectronic devices (Conference Presentation)

NASA Astrophysics Data System (ADS)

Li, Gang; Han, Qifeng; Yang, Yang; Bae, Sang-Hoon; Sun, Pengyu

2016-09-01

Hybrid organolead trihalide perovskite (OTP) solar cells have developed as a promising candidate in photovoltaics due to their excellent properties including a direct bandgap, strong absorption coefficient, long carrier lifetime, and high mobility. Most recently, formamidinium (NH2CH=NH2+ or FA) lead iodide (FAPbI3) has attracted significant attention due to several advantages: (1) the larger organic FA cation can replace the MA cation and form a more symmetric crystal structure, (2) the smaller bandgap of FAPbI3 allows for near infrared (NIR) absorption, and (3) FAPbI3 has an elevated decomposition temperature and thus potential to improve stability. Single crystals provide an excellent model system to study the intrinsic electrical and optical properties of these materials due to their high purity, which is particularly important to understand the limits of these materials. In this work, we report the growth of large ( 5 millimeter size) single crystal FAPbI3 using a novel liquid based crystallization method. The single crystal FAPbI3 demonstrated a δ-phase to α-phase transition with a color change from yellow to black when heated to 185°C within approximately two minutes. The crystal structures of the two phases were identified and the PL emission peak of the α-phase FAPbI3 (820 nm) shows clear red-shift compared to the FAPbI3 thin film (805 nm). The FAPbI3 single crystal shows a long carrier lifetime of 484 ns, a high carrier mobility of 4.4 cm2·V-1·s-1, and even more interestingly a conductivity of 1.1 × 10-7(ohm·cm)-1, which is approximately one order of magnitude higher than that of the MAPbI3 single crystal. Finally, high performance photoconductivity type photodetectors were successfully demonstrated using the single crystal FAPbI3.

Silicon Dioxide Thin Film Mediated Single Cell Nucleic Acid Isolation

PubMed Central

Bogdanov, Evgeny; Dominova, Irina; Shusharina, Natalia; Botman, Stepan; Kasymov, Vitaliy; Patrushev, Maksim

2013-01-01

A limited amount of DNA extracted from single cells, and the development of single cell diagnostics make it necessary to create a new highly effective method for the single cells nucleic acids isolation. In this paper, we propose the DNA isolation method from biomaterials with limited DNA quantity in sample, and from samples with degradable DNA based on the use of solid-phase adsorbent silicon dioxide nanofilm deposited on the inner surface of PCR tube. PMID:23874571

Shock Equation of State of Multi-Phase Epoxy-Based Composite (Al-MnO2-Epoxy)

DTIC Science & Technology

2010-10-01

single stage light gas gun , two...using three different loading techniques— single stage light gas gun , two stage light gas gun , and explosive loading—with multiple diagnostic...wave speed. B. Single stage gas gun loading experiments Four gas gun -driven equation of state experiments were conducted at NSWC-Indian Head using

Experimental Investigation of two-phase nitrogen Cryo transfer line

NASA Astrophysics Data System (ADS)

Singh, G. K.; Nimavat, H.; Panchal, R.; Garg, A.; Srikanth, GLN; Patel, K.; Shah, P.; Tanna, V. L.; Pradhan, S.

2017-02-01

A 6-m long liquid nitrogen based cryo transfer line has been designed, developed and tested at IPR. The test objectives include the thermo-hydraulic characteristics of Cryo transfer line under single phase as well as two phase flow conditions. It is always easy in experimentation to investigate the thermo-hydraulic parameters in case of single phase flow of cryogen but it is real challenge when one deals with the two phase flow of cryogen due to availibity of mass flow measurements (direct) under two phase flow conditions. Established models have been reported in the literature where one of the well-known model of Lockhart-Martenelli relationship has been used to determine the value of quality at the outlet of Cryo transfer line. Under homogenous flow conditions, by taking the ratio of the single-phase pressure drop and the two-phase pressure drop, we estimated the quality at the outlet. Based on these equations, vapor quality at the outlet of the transfer line was predicted at different heat loads. Experimental rresults shown that from inlet to outlet, there is a considerable increment in the pressure drop and vapour quality of the outlet depending upon heat load and mass flow rate of nitrogen flowing through the line.

A solution-based single-molecule study of surface-bound PBIs: solvent-mediated environmental effects on molecular flexibility.

PubMed

Lee, Ji-Eun; Han, Ye Ri; Ham, Sujin; Jun, Chul-Ho; Kim, Dongho

2017-11-08

We have investigated the fundamental photophysical properties of surface-bound perylene bisimide (PBI) molecules in a solution-phase at the single-molecule level. By efficient immobilization of single PBIs on glass, we were able to simultaneously monitor fluorescence intensity trajectories, fluorescence lifetimes, and emission spectra of individual PBIs in organic and aqueous media using confocal microscopy. We showed that the fluorescence dynamics of single PBIs in the solution phase is highly dependent on their local and chemical environments. Furthermore, we visualized different spatial-fluctuations of surface-bound PBIs using defocused wide-field imaging. While PBIs show more steric flexibility in organic media, the flexible motion of PBI molecules in aqueous solution is relatively prohibited due to a cage effect by a hydrogen bonding network, which is previously unobserved. Our method opens up a new possibility to investigate the photophysical properties of multi-chromophoric systems in various solvents at the single-molecule level for developing optimal molecular devices such as water-proof devices.

Single-shot velocity-map imaging of attosecond light-field control at kilohertz rate.

PubMed

Süssmann, F; Zherebtsov, S; Plenge, J; Johnson, Nora G; Kübel, M; Sayler, A M; Mondes, V; Graf, C; Rühl, E; Paulus, G G; Schmischke, D; Swrschek, P; Kling, M F

2011-09-01

High-speed, single-shot velocity-map imaging (VMI) is combined with carrier-envelope phase (CEP) tagging by a single-shot stereographic above-threshold ionization (ATI) phase-meter. The experimental setup provides a versatile tool for angle-resolved studies of the attosecond control of electrons in atoms, molecules, and nanostructures. Single-shot VMI at kHz repetition rate is realized with a highly sensitive megapixel complementary metal-oxide semiconductor camera omitting the need for additional image intensifiers. The developed camera software allows for efficient background suppression and the storage of up to 1024 events for each image in real time. The approach is demonstrated by measuring the CEP-dependence of the electron emission from ATI of Xe in strong (≈10(13) W/cm(2)) near single-cycle (4 fs) laser fields. Efficient background signal suppression with the system is illustrated for the electron emission from SiO(2) nanospheres. © 2011 American Institute of Physics

Recent advances in the CRANK software suite for experimental phasing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pannu, Navraj S., E-mail: raj@chem.leidenuniv.nl; Waterreus, Willem-Jan; Skubák, Pavol

2011-04-01

Recent developments in the CRANK software suite for experimental phasing have led to many more structures being built automatically. For its first release in 2004, CRANK was shown to effectively detect and phase anomalous scatterers from single-wavelength anomalous diffraction data. Since then, CRANK has been significantly improved and many more structures can be built automatically with single- or multiple-wavelength anomalous diffraction or single isomorphous replacement with anomalous scattering data. Here, the new algorithms that have been developed that have led to these substantial improvements are discussed and CRANK’s performance on over 100 real data sets is shown. The latest versionmore » of CRANK is freely available for download at http://www.bfsc.leidenuniv.nl/software/crank/ and from CCP4 (http://www.ccp4.ac.uk/)« less

Investigation of the Temperature Fluctuation of Single-Phase Fluid Based Microchannel Heat Sink.

PubMed

Wang, Tao; Wang, Jiejun; He, Jian; Wu, Chuangui; Luo, Wenbo; Shuai, Yao; Zhang, Wanli; Lee, Chengkuo

2018-05-10

The temperature fluctuation in a single-phase microchannel heat sink (MCHS) is investigated using the integrated temperature sensors with deionized water as the coolant. Results show that the temperature fluctuation in single phase is not negligible. The causes of the temperature fluctuation are revealed based on both simulation and experiment. It is found that the inlet temperature fluctuation and the gas bubbles separated out from coolant are the main causes. The effect of the inlet temperature fluctuation is global, where the temperatures at different locations change simultaneously. Meanwhile, the gas bubble effect is localized where the temperature changes at different locations are not synchronized. In addition, the relation between temperature fluctuation and temperature gradient is established. The temperature fluctuation increases with the temperature gradient accordingly.

Phase transition sequence in ferroelectric Aurivillius compounds investigated by single crystal X-ray diffraction

NASA Astrophysics Data System (ADS)

Boullay, P.; Tellier, J.; Mercurio, D.; Manier, M.; Zuñiga, F. J.; Perez-Mato, J. M.

2012-09-01

The investigation of the phase transition sequence in SrBi2Ta2O9 (SBT) and SrBi2Nb2O9 (SBN) is reported using single-crystal X-ray diffraction. By monitoring specific reflections as a function of temperature, sensitive either to the superstructure formation or to polar displacements, it was possible to check the existence or not of an intermediate phase. This latter was confirmed in SBT, but within experimental accuracy could not be detected in SBN.

A Military-Relevant Model of Closed Concussive Head Injury: Longitudinal Studies Characterizing and Validating Single and Repetitive mTBI

DTIC Science & Technology

2014-10-01

Research Program (CCCRP). Provided in this Year 2 Annual Report are the results of our Phase I studies focused on characterizing the neuropathologic...effects of a single concussive impact to repeated concussive impacts using the PCI model. Phase I studies have been completed and these results set...the foundation for Phase II studies designed to evaluate the effects of repeated concussions that occur prior to and after the resolution of the

Copenhagen's single system premise prevents a unified view of integer and fractional quantum hall effect

NASA Astrophysics Data System (ADS)

Post, Evert Jan

1999-05-01

This essay presents conclusive evidence of the impermissibility of Copenhagen's single system interpretation of the Schroedinger process. The latter needs to be viewed as a tool exclusively describing phase and orientation randomized ensembles and is not be used for isolated single systems. Asymptotic closeness of single system and ensemble behavior and the rare nature of true single system manifestations have prevented a definitive identification of this Copenhagen deficiency over the past three quarter century. Quantum uncertainty so becomes a basic trade mark of phase and orientation disordered ensembles. The ensuing void of usable single system tools opens a new inquiry for tools without statistical connotations. Three, in part already known, period integrals here identified as flux, charge and action counters emerge as diffeo-4 invariant tools fully compatible with the demands of the general theory of relativity. The discovery of the quantum Hall effect has been instrumental in forcing a distinction between ensemble disorder as in the normal Hall effect versus ensemble order in the plateau states. Since the order of the latter permits a view of the plateau states as a macro- or meso-scopic single system, the period integral description applies, yielding a straightforward unified description of integer and fractional quantum Hall effects.

Cesium vacancy ordering in phase-separated C s x F e 2 - y S e 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taddei, K. M.; Sturza, M.; Chung, D. Y.

2015-09-01

By simultaneously displaying magnetism and superconductivity in a single phase, the iron based superconductors provide a model system for the study of magnetism’s role in superconductivity. The class of intercalated iron selenide superconductors is unique amongst these in having the additional property of phase separation and coexistence of two distinct phases - one majority phase with iron vacancy ordering and strong antiferromagnetism and the other a poorly understood minority microscopic phase with a contested structure. Adding to the intrigue, the majority phase has never been found to show superconductivity on its own while the minority phase has never been successfullymore » synthesized separate from the majority phase. In order to better understand this minority phase, a series of high quality CsxFe2-ySe2 single crystals with (0.8 ≤ x ≤ 1; 0 ≤ y ≤ 0.3) were grown and studied. Neutron and x-ray powder diffraction performed on ground crystals show the average structure of the minority phase to be I4/mmm, however, the temperature evolution of its lattice parameters shows it to be distinct from the high temperature I4/mmm parent structure. Neutron and x-ray diffraction experiments performed on single crystal samples reveal the presence of previously unobserved discrete superlattice reflections that remove the degeneracy of the Cs sites in both the majority and minority phases and reduce their structural symmetries from body-centered to primitive. Group theoretical analysis in conjunction with structural modeling shows that the observed superlattice reflections originate from a three-dimensional Cs vacancy ordering in the minority phase. This model predicts a 25% vacancy of the Cs site which is consistent with the site’s refined occupancy. Magnetization measurements performed in tandem with neutron single crystal diffraction provide evidence that the minority phase is the host of superconductivity. Our results also reveal a superconducting dome in which the superconducting transition temperature varies as a function of the valence of iron.« less

Single photon at a configurable quantum-memory-based beam splitter

NASA Astrophysics Data System (ADS)

Guo, Xianxin; Mei, Yefeng; Du, Shengwang

2018-06-01

We report the demonstration of a configurable coherent quantum-memory-based beam splitter (BS) for a single-photon wave packet making use of laser-cooled 85Rb atoms and electromagnetically induced transparency. The single-photon wave packet is converted (stored) into a collective atomic spin state and later retrieved (split) into two nearly opposing directions. The storage time, beam-splitting ratio, and relative phase are configurable and can be dynamically controlled. We experimentally confirm that such a BS preserves the quantum particle nature of the single photon and the coherence between the two split wave packets of the single photon.

Study of the phase transformation of single particles of Ga2O3 by UV-Raman spectroscopy and high-resolution TEM.

PubMed

Wang, Xiang; Xu, Qian; Fan, Fengtao; Wang, Xiuli; Li, Mingrun; Feng, Zhaochi; Li, Can

2013-09-01

By taking advantage of UV-Raman spectroscopy and high-resolution TEM (HRTEM), combined with the focused ion beam (FIB) technique, the transformation from GaOOH into α-Ga2O3 and then into β-Ga2O3 was followed. We found that the stepwise transformations took place from the surface region before developing into the bulk of single particles without particle agglomeration and growth. During the transformation from GaOOH into α-Ga2O3, the elimination of water vapor through the dehydroxylation of GaOOH resulted in the formation of micropores in the single particles, whilst maintaining their particle size. For the phase transformation from α-Ga2O3 into β-Ga2O3, the nucleation of β-Ga2O3 was found to occur at the surface defects and this process could be retarded by occupying these defects with a small amount of La2O3. By finely controlling the process of the phase transformation, the β-Ga2O3 domains gradually developed from the surface into the bulk of the single particles without particle agglomeration. Therefore, the surface structure of the α-Ga2O3 single particles can be easily tuned and a particle with an α@β core-shell phase structure has been obtained. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Deterministic nonlinear phase gates induced by a single qubit

NASA Astrophysics Data System (ADS)

Park, Kimin; Marek, Petr; Filip, Radim

2018-05-01

We propose deterministic realizations of nonlinear phase gates by repeating a finite sequence of non-commuting Rabi interactions between a harmonic oscillator and only a single two-level ancillary qubit. We show explicitly that the key nonclassical features of the ideal cubic phase gate and the quartic phase gate are generated in the harmonic oscillator faithfully by our method. We numerically analyzed the performance of our scheme under realistic imperfections of the oscillator and the two-level system. The methodology is extended further to higher-order nonlinear phase gates. This theoretical proposal completes the set of operations required for continuous-variable quantum computation.

Single-Phase Single-Stage Grid Tied Solar PV System with Active Power Filtering Using Power Balance Theory

NASA Astrophysics Data System (ADS)

Singh, Yashi; Hussain, Ikhlaq; Singh, Bhim; Mishra, Sukumar

2018-06-01

In this paper, power quality features such as harmonics mitigation, power factor correction with active power filtering are addressed in a single-stage, single-phase solar photovoltaic (PV) grid tied system. The Power Balance Theory (PBT) with perturb and observe based maximum power point tracking algorithm is proposed for the mitigation of power quality problems in a solar PV grid tied system. The solar PV array is interfaced to a single phase AC grid through a Voltage Source Converter (VSC), which provides active power flow from a solar PV array to the grid as well as to the load and it performs harmonics mitigation using PBT based control. The solar PV array power varies with sunlight and due to this, the solar PV grid tied VSC works only 8-10 h per day. At night, when PV power is zero, the VSC works as an active power filter for power quality improvement, and the load active power is delivered by the grid to the load connected at the point of common coupling. This increases the effective utilization of a VSC. The system is modelled and simulated using MATLAB and simulated responses of the system at nonlinear loads and varying environmental conditions are also validated experimentally on a prototype developed in the laboratory.

From few-cycle femtosecond pulse to single attosecond pulse-controlling and tracking electron dynamics with attosecond precision

NASA Astrophysics Data System (ADS)

Wang, He

The few-cycle femtosecond laser pulse has proved itself to be a powerful tool for controlling the electron dynamics inside atoms and molecules. By applying such few-cycle pulses as a driving field, single isolated attosecond pulses can be produced through the high-order harmonic generation process, which provide a novel tool for capturing the real time electron motion. The first part of the thesis is devoted to the state of the art few-cycle near infrared (NIR) laser pulse development, which includes absolute phase control (carrier-envelope phase stabilization), amplitude control (power stabilization), and relative phase control (pulse compression and shaping). Then the double optical gating (DOG) method for generating single attosecond pulses and the attosecond streaking experiment for characterizing such pulses are presented. Various experimental limitations in the attosecond streaking measurement are illustrated through simulation. Finally by using the single attosecond pulses generated by DOG, an attosecond transient absorption experiment is performed to study the autoionization process of argon. When the delay between a few-cycle NIR pulse and a single attosecond XUV pulse is scanned, the Fano resonance shapes of the argon autoionizing states are modified by the NIR pulse, which shows the direct observation and control of electron-electron correlation in the temporal domain.

Optical single side-band Nyquist PAM-4 transmission using dual-drive MZM modulation and direct detection.

PubMed

Zhu, Mingyue; Zhang, Jing; Yi, Xingwen; Ying, Hao; Li, Xiang; Luo, Ming; Song, Yingxiong; Huang, Xiatao; Qiu, Kun

2018-03-19

We present the design and optimization of the optical single side-band (SSB) Nyquist four-level pulse amplitude modulation (PAM-4) transmission using dual-drive Mach-Zehnder modulator (DDMZM)modulation and direct detection (DD), aiming at the C-band cost-effective, high-speed and long-distance transmission. At the transmitter, the laser line width should be small to avoid the phase noise to amplitude noise conversion and equalization-enhanced phase noise due to the large chromatic dispersion (CD). The optical SSB signal is generated after optimizing the optical modulation index (OMI) and hence the minimum phase condition which is required by the Kramers-Kronig (KK) receiver can also be satisfied. At the receiver, a simple AC-coupled photodiode (PD) is used and a virtual carrier is added for the KK operation to alleviate the signal-to-signal beating interference (SSBI).A Volterra filter (VF) is cascaded for remaining nonlinearities mitigation. When the fiber nonlinearity becomes significant, we elect to use an optical band-pass filter with offset filtering. It can suppress the simulated Brillouin scattering and the conjugated distortion by filtering out the imaging frequency components. With our design and optimization, we achieve single-channel, single polarization 102.4-Gb/s Nyquist PAM-4 over 800-km standard single-mode fiber (SSMF).

Single-Phase Single-Stage Grid Tied Solar PV System with Active Power Filtering Using Power Balance Theory

NASA Astrophysics Data System (ADS)

Singh, Yashi; Hussain, Ikhlaq; Singh, Bhim; Mishra, Sukumar

2018-03-01

In this paper, power quality features such as harmonics mitigation, power factor correction with active power filtering are addressed in a single-stage, single-phase solar photovoltaic (PV) grid tied system. The Power Balance Theory (PBT) with perturb and observe based maximum power point tracking algorithm is proposed for the mitigation of power quality problems in a solar PV grid tied system. The solar PV array is interfaced to a single phase AC grid through a Voltage Source Converter (VSC), which provides active power flow from a solar PV array to the grid as well as to the load and it performs harmonics mitigation using PBT based control. The solar PV array power varies with sunlight and due to this, the solar PV grid tied VSC works only 8-10 h per day. At night, when PV power is zero, the VSC works as an active power filter for power quality improvement, and the load active power is delivered by the grid to the load connected at the point of common coupling. This increases the effective utilization of a VSC. The system is modelled and simulated using MATLAB and simulated responses of the system at nonlinear loads and varying environmental conditions are also validated experimentally on a prototype developed in the laboratory.

Beyond the Quantum Hall Effect: New Phases of 2D Electrons at High Magnetic Field

NASA Astrophysics Data System (ADS)

Eisenstein, James

2007-03-01

In this talk I will discuss recent experiments on high mobility single and double layer 2D electron systems in which collective phases lying outside the usual quantum Hall effect paradigm have been detected and studied. For example, in single layer 2D systems near half-filling of highly excited Landau levels new states characterized by a massive anisotropy in the electrical resistivity of the sample are observed at very low temperature. The anisotropy has been widely interpreted as the signature of a new class of correlated electron phases which incorporate a stripe-like charge density modulation. Orientational ordering of small striped domains at low temperatures accounts for the resistive anisotropy and is reminiscent of the isotropic-to-nematic phase transition in classical liquid crystals. Double layer 2D electron systems possess collective phases not present in single layer systems. In particular, when the total number of electrons in the bilayer equals the degeneracy of a single Landau level, an unusual phase appears at small layer separation. This phase possesses a novel broken symmetry, spontaneous interlayer phase coherence, which has a number of dramatic experimental signatures. The interlayer tunneling conductance develops a strong and very sharp resonance around zero bias resembling the dc Josephson effect. At the same time, both the longitudinal and Hall resistances of the sample vanish at low temperatures when currents are driven in opposite directions through the two layers. These, and other observations are broadly consistent with theories in which the broken symmetry phase can equivalently be described as a pseudospin ferromagnet or an (imperfect) excitonic superfluid. This work reflects a collaboration with M.P. Lilly, K.B. Cooper, I.B. Spielman, M. Kellogg, L.A. Tracy, L.N. Pfeiffer, and K.W. West.

Precise single-qubit control of the reflection phase of a photon mediated by a strongly-coupled ancilla–cavity system

NASA Astrophysics Data System (ADS)

Motzoi, F.; Mølmer, K.

2018-05-01

We propose to use the interaction between a single qubit atom and a surrounding ensemble of three level atoms to control the phase of light reflected by an optical cavity. Our scheme employs an ensemble dark resonance that is perturbed by the qubit atom to yield a single-atom single photon gate. We show here that off-resonant excitation towards Rydberg states with strong dipolar interactions offers experimentally-viable regimes of operations with low errors (in the 10‑3 range) as required for fault-tolerant optical-photon, gate-based quantum computation. We also propose and analyze an implementation within microwave circuit-QED, where a strongly-coupled ancilla superconducting qubit can be used in the place of the atomic ensemble to provide high-fidelity coupling to microwave photons.

Single Crystal Faceplate Evaluation

DTIC Science & Technology

1993-10-25

conventional powder phosphor. The utility of garnets is amplified by the high state of the art of liquid phase epitaxy ( LPE ). Liquid phase epitaxy of...7]. Much the research at Allied-Signal, Inc. in garnet layer growth has been involved with the kinetics of crystallization of garnet from LPE melts...acceptable resolution and light output characteristics. Single crystal faceplates being evaluated are composed of yttrium aluminum garnet (YAG) with an

Method for thermal processing alumina-enriched spinel single crystals

DOEpatents

Jantzen, C.M.

1995-05-09

A process for age-hardening alumina-rich magnesium aluminum spinel to obtain the desired combination of characteristics of hardness, clarity, flexural strength and toughness comprises selection of the time-temperature pair for isothermal heating followed by quenching. The time-temperature pair is selected from the region wherein the precipitate groups have the characteristics sought. The single crystal spinel is isothermally heated and will, if heated long enough pass from its single phase through two pre-precipitates and two metastable precipitates to a stable secondary phase precipitate within the spinel matrix. Quenching is done slowly at first to avoid thermal shock, then rapidly. 12 figs.

Effect of zone size on the convergence of exact solutions for diffusion in single phase systems with planar, cylindrical or spherical geometry

NASA Technical Reports Server (NTRS)

Unnam, J.; Tenney, D. R.

1981-01-01

Exact solutions for diffusion in single phase binary alloy systems with constant diffusion coefficient and zero-flux boundary condition have been evaluated to establish the optimum zone size of applicability. Planar, cylindrical and spherical interface geometry, and finite, singly infinite, and doubly infinite systems are treated. Two solutions are presented for each geometry, one well suited to short diffusion times, and one to long times. The effect of zone-size on the convergence of these solutions is discussed. A generalized form of the diffusion solution for doubly infinite systems is proposed.

Supramolecular Assembly of Single-Source Metal-Chalcogenide Nanocrystal Precursors.

PubMed

Smith, Stephanie C; Bryks, Whitney; Tao, Andrea R

2018-05-28

In this Feature Article, we discuss our recent work in the synthesis of novel supramolecular precursors for semiconductor nanocrystals. Metal chalcogenolates that adopt liquid crystalline phases are employed as single-source precursors that template the growth of shaped solid-state nanocrystals. Supramolecular assembly is programmed by both precursor chemical composition and molecular parameters such alkyl chain length, steric bulk, and the intercalation of halide ions. Here, we explore the various design principles that enable the rational synthesis of these single-source precursors, their liquid crystalline phases, and the various semiconductor nanocrystal products that can be generated by thermolysis, ranging from highly anisotropic two-dimensional nanosheets and nanodisks to spheres.

Time-alternating method based on single-sideband holography with half-zone-plate processing for the enlargement of viewing zones.

PubMed

Mishina, T; Okano, F; Yuyama, I

1999-06-10

The single-sideband method of holography, as is well known, cuts off beams that come from conjugate images for holograms produced in the Fraunhofer region and from objects with no phase components. The single-sideband method with half-zone-plate processing is also effective in the Fresnel region for beams from an object that has phase components. However, this method restricts the viewing zone to a narrow range. We propose a method to improve this restriction by time-alternating switching of hologram patterns and a spatial filter set on the focal plane of a reconstruction lens.

Cesium vacancy ordering in phase-separated C s x F e 2 - y S e 2

DOE PAGES

Taddei, Keith M.; Sturza, M.; Chung, Duck -Yung; ...

2015-09-14

By simultaneously displaying magnetism and superconductivity in a single phase, the iron-based superconductors provide a model system for the study of magnetism's role in superconductivity. The class of intercalated iron selenide superconductors is unique among these in having the additional property of phase separation and coexistence of two distinct phases—one majority phase with iron vacancy ordering and strong antiferromagnetism, and the other a poorly understood minority microscopic phase with a contested structure. Adding to the intrigue, the majority phase has never been found to show superconductivity on its own while the minority phase has never been successfully synthesized separate frommore » the majority phase. In order to better understand this minority phase, a series of high-quality Cs xFe 2–ySe 2 single crystals with (0.8 ≤ x ≤ 1;0 ≤ y ≤ 0.3) were grown and studied. Neutron and x-ray powder diffraction performed on ground crystals show that the average I4/mmm structure of the minority phase is distinctly different from the high-temperature I4/mmm parent structure. Moreover, single-crystal diffraction reveals the presence of discrete superlattice reflections that remove the degeneracy of the Cs sites in both the majority and minority phases and reduce their structural symmetries from body centered to primitive. Group theoretical analysis in conjunction with structural modeling shows that the observed superlattice reflections originate from three-dimensional Cs vacancy ordering. This model predicts a 25% vacancy of the Cs site in the minority phase which is consistent with the site's refined occupancy. Magnetization measurements performed in tandem with neutron single-crystal diffraction provide evidence that the minority phase is the host of superconductivity. Lastly, our results also reveal a superconducting dome in which the superconducting transition temperature varies as a function of the nominal valence of iron.« less

Vacuum-induced Berry phases in single-mode Jaynes-Cummings models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Yu; Wei, L. F.; Jia, W. Z.

2010-10-15

Motivated by work [Phys. Rev. Lett. 89, 220404 (2002)] for detecting the vacuum-induced Berry phases with two-mode Jaynes-Cummings models (JCMs), we show here that, for a parameter-dependent single-mode JCM, certain atom-field states also acquired photon-number-dependent Berry phases after the parameter slowly changed and eventually returned to its initial value. This geometric effect related to the field quantization still exists, even if the field is kept in its vacuum state. Specifically, a feasible Ramsey interference experiment with a cavity quantum electrodynamics system is designed to detect the vacuum-induced Berry phase.

Ultrafast electric phase control of a single exciton qubit

NASA Astrophysics Data System (ADS)

Widhalm, Alex; Mukherjee, Amlan; Krehs, Sebastian; Sharma, Nandlal; Kölling, Peter; Thiede, Andreas; Reuter, Dirk; Förstner, Jens; Zrenner, Artur

2018-03-01

We report on the coherent phase manipulation of quantum dot excitons by electric means. For our experiments, we use a low capacitance single quantum dot photodiode which is electrically controlled by a custom designed SiGe:C BiCMOS chip. The phase manipulation is performed and quantified in a Ramsey experiment, where ultrafast transient detuning of the exciton energy is performed synchronous to double pulse π/2 ps laser excitation. We are able to demonstrate electrically controlled phase manipulations with magnitudes up to 3π within 100 ps which is below the dephasing time of the quantum dot exciton.

Short-term hydro generation and interchange contract scheduling for Swiss Rail

DOE Office of Scientific and Technical Information (OSTI.GOV)

Christoforidis, M.; Awobamise, B.; Tong, S.

This paper describes the Short-Term Resource Scheduling (STRS) function that has been developed by Siemens-Empros as part of the new SBB/Direktion Kraftwerk (Swiss Rail) Energy Management System. Optimal scheduling of the single-phase hydro plants, single-phase and three-phase energy accounts, and purchase and sale of three phase energy subject to a multitude of physical and contractual constraints (including spinning and regulating reserve requirements), is the main objective of the STRS function. The operations planning horizon of STRS is one day to one week using an hourly time increment.

Isolated Attosecond Pulse Generation without the Need to Stabilize the Carrier-Envelope Phase of Driving Lasers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gilbertson, Steve; Khan, Sabih D.; Wu Yi

2010-08-27

Single isolated attosecond pulses can be extracted from a pulse train with an ultrafast gate in the generation target. By setting the gate width sufficiently narrow with the generalized double optical gating, we demonstrate that single isolated attosecond pulses can be generated with any arbitrary carrier-envelope phase value of the driving laser. The carrier-envelope phase only affects the photon flux, not the pulse duration or contrast. Our results show that isolated attosecond pulses can be generated using carrier-envelope phase unstabilized 23 fs pulses directly from chirped pulse amplifiers.

Solid-solution CrCoCuFeNi high-entropy alloy thin films synthesized by sputter deposition

DOE PAGES

An, Zhinan; Jia, Haoling; Wu, Yueying; ...

2015-05-04

The concept of high configurational entropy requires that the high-entropy alloys (HEAs) yield single-phase solid solutions. However, phase separations are quite common in bulk HEAs. A five-element alloy, CrCoCuFeNi, was deposited via radio frequency magnetron sputtering and confirmed to be a single-phase solid solution through the high-energy synchrotron X-ray diffraction, energy-dispersive spectroscopy, wavelength-dispersive spectroscopy, and transmission electron microscopy. The formation of the solid-solution phase is presumed to be due to the high cooling rate of the sputter-deposition process.

Single-step reinitialization and extending algorithms for level-set based multi-phase flow simulations

NASA Astrophysics Data System (ADS)

Fu, Lin; Hu, Xiangyu Y.; Adams, Nikolaus A.

2017-12-01

We propose efficient single-step formulations for reinitialization and extending algorithms, which are critical components of level-set based interface-tracking methods. The level-set field is reinitialized with a single-step (non iterative) "forward tracing" algorithm. A minimum set of cells is defined that describes the interface, and reinitialization employs only data from these cells. Fluid states are extrapolated or extended across the interface by a single-step "backward tracing" algorithm. Both algorithms, which are motivated by analogy to ray-tracing, avoid multiple block-boundary data exchanges that are inevitable for iterative reinitialization and extending approaches within a parallel-computing environment. The single-step algorithms are combined with a multi-resolution conservative sharp-interface method and validated by a wide range of benchmark test cases. We demonstrate that the proposed reinitialization method achieves second-order accuracy in conserving the volume of each phase. The interface location is invariant to reapplication of the single-step reinitialization. Generally, we observe smaller absolute errors than for standard iterative reinitialization on the same grid. The computational efficiency is higher than for the standard and typical high-order iterative reinitialization methods. We observe a 2- to 6-times efficiency improvement over the standard method for serial execution. The proposed single-step extending algorithm, which is commonly employed for assigning data to ghost cells with ghost-fluid or conservative interface interaction methods, shows about 10-times efficiency improvement over the standard method while maintaining same accuracy. Despite their simplicity, the proposed algorithms offer an efficient and robust alternative to iterative reinitialization and extending methods for level-set based multi-phase simulations.

LIDAR forest inventory with single-tree, double- and single-phase procedures

Treesearch

Robert C. Parker; David L. Evans

2009-01-01

Light Detection and Ranging (LIDAR) data at 0.5- to 2-m postings were used with doublesample, stratified inventory procedures involving single-tree attribute relationships in mixed, natural, and planted species stands to yield sampling errors (one-half the confidence interval expressed as a percentage of the mean) ranging from ±2.1 percent to ±11.5...

0 - π Quantum transition in a carbon nanotube Josephson junction: Universal phase dependence and orbital degeneracy

NASA Astrophysics Data System (ADS)

Delagrange, R.; Weil, R.; Kasumov, A.; Ferrier, M.; Bouchiat, H.; Deblock, R.

2018-05-01

In a quantum dot hybrid superconducting junction, the behavior of the supercurrent is dominated by Coulomb blockade physics, which determines the magnetic state of the dot. In particular, in a single level quantum dot singly occupied, the sign of the supercurrent can be reversed, giving rise to a π-junction. This 0 - π transition, corresponding to a singlet-doublet transition, is then driven by the gate voltage or by the superconducting phase in the case of strong competition between the superconducting proximity effect and Kondo correlations. In a two-level quantum dot, such as a clean carbon nanotube, 0- π transitions exist as well but, because more cotunneling processes are allowed, are not necessarily associated to a magnetic state transition of the dot. In this proceeding, after a review of 0- π transitions in Josephson junctions, we present measurements of current-phase relation in a clean carbon nanotube quantum dot, in the single and two-level regimes. In the single level regime, close to orbital degeneracy and in a regime of strong competition between local electronic correlations and superconducting proximity effect, we find that the phase diagram of the phase-dependent transition is a universal characteristic of a discontinuous level-crossing quantum transition at zero temperature. In the case where the two levels are involved, the nanotube Josephson current exhibits a continuous 0 - π transition, independent of the superconducting phase, revealing a different physical mechanism of the transition.

Play Caging Benefits the Behavior of Singly Housed Laboratory Rhesus Macaques (Macaca mulatta)

PubMed Central

Griffis, Caroline M; Martin, Allison L; Perlman, Jaine E; Bloomsmith, Mollie A

2013-01-01

This study addresses a recommendation in The Guide for the Care and Use of Laboratory Animals to provide singly housed nonhuman primates with intermittent access to large, enriched (play) caging. Research on the potential benefits of this type of caging is limited. The present study examines the effects of play caging on behavior, activity, and enrichment use. Singly housed, adult male, rhesus macaques (n = 10) underwent a baseline phase in their home cages, a 2-wk treatment phase with housing in play cages, and a posttreatment phase after returning to their home cages. Each subject underwent focal behavioral observations (n = 10; duration 30 min each) during each study phase, for a total of 150 h of data collection. Results showed increases in locomotion and enrichment use and a trend toward decreased abnormal behavior while subjects were in the play cage, with the durations of these behaviors returning to baseline levels after treatment. Anxiety-related behaviors decreased between the treatment and posttreatment phases but not between baseline and treatment, suggesting that outside factors may have influenced the decline. During the treatment phase, subjects spent more time in the upper quadrants of the play caging and preferred a mirror and forage boards as forms of enrichment. The greatest behavioral improvement occurred during the first week in the play cage. This study provides evidence to support the benefits of play caging for singly housed rhesus macaques. PMID:24041207

High performance of SDC and GDC core shell type composite electrolytes using methane as a fuel for low temperature SOFC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Irshad, Muneeb; Siraj, Khurram, E-mail: razahussaini786@gmail.com, E-mail: khurram.uet@gmail.com; Javed, Fayyaz

Nanocomposites Samarium doped Ceria (SDC), Gadolinium doped Ceria (GDC), core shell SDC amorphous Na{sub 2}CO{sub 3} (SDCC) and GDC amorphous Na{sub 2}CO{sub 3} (GDCC) were synthesized using co-precipitation method and then compared to obtain better solid oxide electrolytes materials for low temperature Solid Oxide Fuel Cell (SOFCs). The comparison is done in terms of structure, crystallanity, thermal stability, conductivity and cell performance. In present work, XRD analysis confirmed proper doping of Sm and Gd in both single phase (SDC, GDC) and dual phase core shell (SDCC, GDCC) electrolyte materials. EDX analysis validated the presence of Sm and Gd in bothmore » single and dual phase electrolyte materials; also confirming the presence of amorphous Na{sub 2}CO{sub 3} in SDCC and GDCC. From TGA analysis a steep weight loss is observed in case of SDCC and GDCC when temperature rises above 725 °C while SDC and GDC do not show any loss. The ionic conductivity and cell performance of single phase SDC and GDC nanocomposite were compared with core shell GDC/amorphous Na{sub 2}CO{sub 3} and SDC/ amorphous Na{sub 2}CO{sub 3} nanocomposites using methane fuel. It is observed that dual phase core shell electrolytes materials (SDCC, GDCC) show better performance in low temperature range than their corresponding single phase electrolyte materials (SDC, GDC) with methane fuel.« less

Re-creation of single phase, and improvement of magnetic property of CoFe2O4 nanoparticles versus heat treatment

NASA Astrophysics Data System (ADS)

Tran, N.; Kim, D. H.; Phan, T. L.; Dang, N. T.; Bach, T. N.; Manh, D. H.; Lee, B. W.

2018-03-01

Our studies on the crystal characterization and magnetic property of CoFe2O4 nanoparticles (NPs) point out their instability in a specific temperature range. While as-prepared NPs exhibit single phase in a cubic spinel structure, annealing at temperatures T=673-1273 K leads to the development of an impurity phase of Fe2O3. Interestingly, annealing at higher temperatures re-creates the single phase of NPs. This strongly influences their magnetic property. The magnetic inhomogeneity and/or multiple phase exist in as-prepared NPs and in those annealed below 1273 K, better magnetic property is found in the samples with annealing temperature (Tan) higher than 1273 K. Ferromagnetic-paramagnetic phase transition temperatures of these samples are located around 815-850 K, and are less dependent on Tan. At room temperature, their saturation magnetization is located in the range of 41-55 emu/g, while the coercivity can be changed from 600 to 3200 Oe. These results are related to microstructures, structural phases, and exchange interactions between Fe and Co ions situated in the A and B sites of the spinel structure, which are modified by heat treatment.

Gamma knife treatment for refractory epilepsy in seizure focus localized by positron emission tomography/CT★

PubMed Central

Bai, Xia; Wang, Xuemei; Wang, Hongwei; Zhao, Shigang; Han, Xiaodong; Hao, Linjun; Wang, Xiangcheng

2012-01-01

A total of 80 patients with refractory epilepsy were recruited from the Inner Mongolia Medical College Affiliated Hospital. The foci of 60% of the patients could be positioned using a combined positron emission tomography/CT imaging modality. Hyper- and hypometabolism foci were examined as part of this study. Patients who had abnormal metabolism in positron emission tomography/CT imaging were divided into intermittent-phase group and the seizure-phase group. The intermittent-phase group was further divided into a single-focus group and a multiple-foci group according to the number of seizure foci detected by imaging. Following gamma knife treatment, seizure frequency was significantly lower in the intermittent-phase group and the seizure-phase group. Wieser’s classification reached Grade I or II in nearly 40% of patients. Seizure frequency was significantly lower following treatment, but Wieser’s classification score was significantly higher in the seizure-phase group compared with the intermittent-phase group. Seizure frequency was significantly lower following treatment in the single-focus group, but Wieser’s classification score was significantly higher in the single-focus group as compared with the multiple-foci group. PMID:25317147

Exclusive Liquid Repellency: An Open Multi-Liquid-Phase Technology for Rare Cell Culture and Single-Cell Processing.

PubMed

Li, Chao; Yu, Jiaquan; Schehr, Jennifer; Berry, Scott M; Leal, Ticiana A; Lang, Joshua M; Beebe, David J

2018-05-23

The concept of high liquid repellency in multi-liquid-phase systems (e.g., aqueous droplets in an oil background) has been applied to areas of biomedical research to realize intrinsic advantages not available in single-liquid-phase systems. Such advantages have included minimizing analyte loss, facile manipulation of single-cell samples, elimination of biofouling, and ease of use regarding loading and retrieving of the sample. In this paper, we present generalized design rules for predicting the wettability of solid-liquid-liquid systems (especially for discrimination between exclusive liquid repellency (ELR) and finite liquid repellency) to extend the applications of ELR. We then apply ELR to two model systems with open microfluidic design in cell biology: (1) in situ underoil culture and combinatorial coculture of mammalian cells in order to demonstrate directed single-cell multiencapsulation with minimal waste of samples as compared to stochastic cell seeding and (2) isolation of a pure population of circulating tumor cells, which is required for certain downstream analyses including sequencing and gene expression profiling.

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

DOE PAGES

Mairoser, Thomas; Mundy, Julia A.; Melville, Alexander; ...

2015-07-16

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

Gas-Phase Stability of Negatively Charged Organophosphate Metabolites Produced by Electrospray Ionization and Matrix-Assisted Laser Desorption/Ionization

NASA Astrophysics Data System (ADS)

Asakawa, Daiki; Mizuno, Hajime; Toyo'oka, Toshimasa

2017-12-01

The formation mechanisms of singly and multiply charged organophosphate metabolites by electrospray ionization (ESI) and their gas phase stabilities were investigated. Metabolites containing multiple phosphate groups, such as adenosine 5'-diphosphate (ADP), adenosine 5'-triphosphate (ATP), and D- myo-inositol-1,4,5-triphosphate (IP3) were observed as doubly deprotonated ions by negative-ion ESI mass spectrometry. Organophosphates with multiple negative charges were found to be unstable and often underwent loss of PO3 -, although singly deprotonated analytes were stable. The presence of fragments due to the loss of PO3 - in the negative-ion ESI mass spectra could result in the misinterpretation of analytical results. In contrast to ESI, matrix-assisted laser desorption ionization (MALDI) produced singly charged organophosphate metabolites with no associated fragmentation, since the singly charged anions are stable. The stability of an organophosphate metabolite in the gas phase strongly depends on its charge state. The fragmentations of multiply charged organophosphates were also investigated in detail through density functional theory calculations. [Figure not available: see fulltext.

Structure and magnetic properties of flux grown single crystals of Co3-xFexSn2S2 shandites

NASA Astrophysics Data System (ADS)

Kassem, Mohamed A.; Tabata, Yoshikazu; Waki, Takeshi; Nakamura, Hiroyuki

2016-01-01

We report a successful single crystal growth of the shandite-type half-metallic ferromagnet Co3Sn2S2, and its Fe-substituted compounds, Co3-xFexSn2S2, by employing the flux method. Although Fe3Sn2S2 is unstable phase, we found that using the self Sn flux enables us to obtain single phase crystals up to x=0.53. The chemical composition of the grown plate-shaped single crystals was examined using wavelength-dispersive X-ray spectroscopy. The shandite structure with R 3 ̅m symmetry was confirmed by powder X-ray diffraction and the crystal structure parameters were refined using the Rietveld method. Magnetization measurements show suppression of the ferromagnetic order upon Fe-substitution , as well as in other substituted systems such as In- and Ni-substituted Co3Sn2S2. The almost identical magnetic phase diagrams of the Fe- and In-substituted compounds indicate that the electron number is dominantly significant to the magnetism in the Co-based shandite.

Single-phase Whole-body 64-MDCT Split-bolus Protocol for Pediatric Oncology: Diagnostic Efficacy and Dose Radiation.

PubMed

Scialpi, Michele; Schiavone, Raffaele; D'Andrea, Alfredo; Palumbo, Isabella; Magli, Michelle; Gravante, Sabrina; Falcone, Giuseppe; De Filippi, Claudio; Manganaro, Lucia; Palumbo, Barbara

2015-05-01

To evaluate the image quality and the diagnostic efficacy by single-phase whole-body 64-slice multidetector CT (MDCT) for pediatric oncology. Chest-abdomen-pelvis CT examinations with single-phase split-bolus technique were evaluated for T: detection and delineation of primary tumor (assessment of the extent of the lesion to neighboring tissues), N: regional lymph nodes and M: distant metastasis. Quality scores (5-point scale) were assessed by two radiologists on parenchymal and vascular enhancement. Accurate TNM staging in term of detection and delineation of primary tumor, regional lymph nodes and distant metastasis was obtained in all cases. On the image quality and severity artifact, the Kappa value for the interobserver agreement measure obtained from the analysis was 0.754, (p<0.001), characterizing a very good agreement between observers. Single-pass total body CT split-bolus technique reached the highest overall image quality and an accurate TNM staging in pediatric patients with cancer. Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Quantitative refractive index distribution of single cell by combining phase-shifting interferometry and AFM imaging.

PubMed

Zhang, Qinnan; Zhong, Liyun; Tang, Ping; Yuan, Yingjie; Liu, Shengde; Tian, Jindong; Lu, Xiaoxu

2017-05-31

Cell refractive index, an intrinsic optical parameter, is closely correlated with the intracellular mass and concentration. By combining optical phase-shifting interferometry (PSI) and atomic force microscope (AFM) imaging, we constructed a label free, non-invasive and quantitative refractive index of single cell measurement system, in which the accurate phase map of single cell was retrieved with PSI technique and the cell morphology with nanoscale resolution was achieved with AFM imaging. Based on the proposed AFM/PSI system, we achieved quantitative refractive index distributions of single red blood cell and Jurkat cell, respectively. Further, the quantitative change of refractive index distribution during Daunorubicin (DNR)-induced Jurkat cell apoptosis was presented, and then the content changes of intracellular biochemical components were achieved. Importantly, these results were consistent with Raman spectral analysis, indicating that the proposed PSI/AFM based refractive index system is likely to become a useful tool for intracellular biochemical components analysis measurement, and this will facilitate its application for revealing cell structure and pathological state from a new perspective.

A High-Rate, Single-Crystal Model including Phase Transformations, Plastic Slip, and Twinning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Addessio, Francis L.; Bronkhorst, Curt Allan; Bolme, Cynthia Anne

2016-08-09

An anisotropic, rate-­dependent, single-­crystal approach for modeling materials under the conditions of high strain rates and pressures is provided. The model includes the effects of large deformations, nonlinear elasticity, phase transformations, and plastic slip and twinning. It is envisioned that the model may be used to examine these coupled effects on the local deformation of materials that are subjected to ballistic impact or explosive loading. The model is formulated using a multiplicative decomposition of the deformation gradient. A plate impact experiment on a multi-­crystal sample of titanium was conducted. The particle velocities at the back surface of three crystal orientationsmore » relative to the direction of impact were measured. Molecular dynamics simulations were conducted to investigate the details of the high-­rate deformation and pursue issues related to the phase transformation for titanium. Simulations using the single crystal model were conducted and compared to the high-­rate experimental data for the impact loaded single crystals. The model was found to capture the features of the experiments.« less

Female PFP patients present alterations in eccentric muscle activity but not the temporal order of activation of the vastus lateralis muscle during the single leg triple hop test.

PubMed

Kalytczak, Marcelo Martins; Lucareli, Paulo Roberto Garcia; Dos Reis, Amir Curcio; Bley, André Serra; Biasotto-Gonzalez, Daniela Aparecida; Correa, João Carlos Ferrari; Politti, Fabiano

2018-04-07

This study aimed to compare the concentric and eccentric activity and the temporal order of peak activity of the hip and knee muscles between women with patellofemoral pain (PFP) and healthy women during the single leg triple hop test (SLTHT). Electromyographic (EMG) and Kinematic data were collected from 14 healthy women (CG) and 14 women diagnosed with PFP (PFG) during a single session of the single leg triple hop test. Integral surface electromyography (iEMG) data of the hip and knee muscles in eccentric and concentric phases and the length of time that each muscle needed to reach the maximal peak of muscle activity were calculated. The iEMG in the eccentric phase was significantly higher (p < 0.05) than the concentric phase, for the gluteus maximus and gluteus medius muscles (CG and PFG) and for the vastus lateralis muscle (PFG). The vastus lateralis muscle was the first muscle to reach the highest peak of activity in the PFG, and the third to reach this peak in the CG. In the present study, the activity of the vastus lateralis muscle during the eccentric phase of the jump was greater than concentric phase, as a temporal anticipation of its peak in activity among women with PFP. Copyright © 2018 Elsevier B.V. All rights reserved.

The effect of neutrally buoyant finite-size particles on channel flows in the laminar-turbulent transition regime

NASA Astrophysics Data System (ADS)

Loisel, Vincent; Abbas, Micheline; Masbernat, Olivier; Climent, Eric

2013-12-01

The presence of finite-size particles in a channel flow close to the laminar-turbulent transition is simulated with the Force Coupling Method which allows two-way coupling with the flow dynamics. Spherical particles with channel height-to-particle diameter ratio of 16 are initially randomly seeded in a fluctuating flow above the critical Reynolds number corresponding to single phase flow relaminarization. When steady-state is reached, the particle volume fraction is homogeneously distributed in the channel cross-section (ϕ ≅ 5%) except in the near-wall region where it is larger due to inertia-driven migration. Turbulence statistics (intensity of velocity fluctuations, small-scale vortical structures, wall shear stress) calculated in the fully coupled two-phase flow simulations are compared to single-phase flow data in the transition regime. It is observed that particles increase the transverse r.m.s. flow velocity fluctuations and they break down the flow coherent structures into smaller, more numerous and sustained eddies, preventing the flow to relaminarize at the single-phase critical Reynolds number. When the Reynolds number is further decreased and the suspension flow becomes laminar, the wall friction coefficient recovers the evolution of the laminar single-phase law provided that the suspension viscosity is used in the Reynolds number definition. The residual velocity fluctuations in the suspension correspond to a regime of particulate shear-induced agitation.

Uncertainties in Cloud Phase and Optical Thickness Retrievals from the Earth Polychromatic Imaging Camera (EPIC)

NASA Technical Reports Server (NTRS)

Meyer, Kerry; Yang, Yuekui; Platnick, Steven

2016-01-01

This paper presents an investigation of the expected uncertainties of a single channel cloud optical thickness (COT) retrieval technique, as well as a simple cloud-temperature-threshold-based thermodynamic phase approach, in support of the Deep Space Climate Observatory (DSCOVR) mission. DSCOVR cloud products will be derived from Earth Polychromatic Imaging Camera (EPIC) observations in the ultraviolet and visible spectra. Since EPIC is not equipped with a spectral channel in the shortwave or mid-wave infrared that is sensitive to cloud effective radius (CER), COT will be inferred from a single visible channel with the assumption of appropriate CER values for liquid and ice phase clouds. One month of Aqua MODIS daytime granules from April 2005 is selected for investigating cloud phase sensitivity, and a subset of these granules that has similar EPIC sun-view geometry is selected for investigating COT uncertainties. EPIC COT retrievals are simulated with the same algorithm as the operational MODIS cloud products (MOD06), except using fixed phase-dependent CER values. Uncertainty estimates are derived by comparing the single channel COT retrievals with the baseline bi-spectral MODIS retrievals. Results show that a single channel COT retrieval is feasible for EPIC. For ice clouds, single channel retrieval errors are minimal (less than 2 percent) due to the particle- size insensitivity of the assumed ice crystal (i.e., severely roughened aggregate of hexagonal columns) scattering properties at visible wavelengths, while for liquid clouds the error is mostly limited to within 10 percent, although for thin clouds (COT less than 2) the error can be higher. Potential uncertainties in EPIC cloud masking and cloud temperature retrievals are not considered in this study.

Uncertainties in cloud phase and optical thickness retrievals from the Earth Polychromatic Imaging Camera (EPIC)

PubMed Central

Meyer, Kerry; Yang, Yuekui; Platnick, Steven

2018-01-01

This paper presents an investigation of the expected uncertainties of a single channel cloud optical thickness (COT) retrieval technique, as well as a simple cloud temperature threshold based thermodynamic phase approach, in support of the Deep Space Climate Observatory (DSCOVR) mission. DSCOVR cloud products will be derived from Earth Polychromatic Imaging Camera (EPIC) observations in the ultraviolet and visible spectra. Since EPIC is not equipped with a spectral channel in the shortwave or mid-wave infrared that is sensitive to cloud effective radius (CER), COT will be inferred from a single visible channel with the assumption of appropriate CER values for liquid and ice phase clouds. One month of Aqua MODIS daytime granules from April 2005 is selected for investigating cloud phase sensitivity, and a subset of these granules that has similar EPIC sun-view geometry is selected for investigating COT uncertainties. EPIC COT retrievals are simulated with the same algorithm as the operational MODIS cloud products (MOD06), except using fixed phase-dependent CER values. Uncertainty estimates are derived by comparing the single channel COT retrievals with the baseline bi-spectral MODIS retrievals. Results show that a single channel COT retrieval is feasible for EPIC. For ice clouds, single channel retrieval errors are minimal (< 2%) due to the particle size insensitivity of the assumed ice crystal (i.e., severely roughened aggregate of hexagonal columns) scattering properties at visible wavelengths, while for liquid clouds the error is mostly limited to within 10%, although for thin clouds (COT < 2) the error can be higher. Potential uncertainties in EPIC cloud masking and cloud temperature retrievals are not considered in this study. PMID:29619116

Uncertainties in cloud phase and optical thickness retrievals from the Earth Polychromatic Imaging Camera (EPIC).

PubMed

Meyer, Kerry; Yang, Yuekui; Platnick, Steven

2016-01-01

This paper presents an investigation of the expected uncertainties of a single channel cloud optical thickness (COT) retrieval technique, as well as a simple cloud temperature threshold based thermodynamic phase approach, in support of the Deep Space Climate Observatory (DSCOVR) mission. DSCOVR cloud products will be derived from Earth Polychromatic Imaging Camera (EPIC) observations in the ultraviolet and visible spectra. Since EPIC is not equipped with a spectral channel in the shortwave or mid-wave infrared that is sensitive to cloud effective radius (CER), COT will be inferred from a single visible channel with the assumption of appropriate CER values for liquid and ice phase clouds. One month of Aqua MODIS daytime granules from April 2005 is selected for investigating cloud phase sensitivity, and a subset of these granules that has similar EPIC sun-view geometry is selected for investigating COT uncertainties. EPIC COT retrievals are simulated with the same algorithm as the operational MODIS cloud products (MOD06), except using fixed phase-dependent CER values. Uncertainty estimates are derived by comparing the single channel COT retrievals with the baseline bi-spectral MODIS retrievals. Results show that a single channel COT retrieval is feasible for EPIC. For ice clouds, single channel retrieval errors are minimal (< 2%) due to the particle size insensitivity of the assumed ice crystal (i.e., severely roughened aggregate of hexagonal columns) scattering properties at visible wavelengths, while for liquid clouds the error is mostly limited to within 10%, although for thin clouds (COT < 2) the error can be higher. Potential uncertainties in EPIC cloud masking and cloud temperature retrievals are not considered in this study.

A high capacity data centre network: simultaneous 4-PAM data at 20 Gbps and 2 GHz phase modulated RF clock signal over a single VCSEL carrier

NASA Astrophysics Data System (ADS)

Isoe, G. M.; Wassin, S.; Gamatham, R. R. G.; Leitch, A. W. R.; Gibbon, T. B.

2017-11-01

Optical fibre communication technologies are playing important roles in data centre networks (DCNs). Techniques for increasing capacity and flexibility for the inter-rack/pod communications in data centres have drawn remarkable attention in recent years. In this work, we propose a low complexity, reliable, alternative technique for increasing DCN capacity and flexibility through multi-signal modulation onto a single mode VCSEL carrier. A 20 Gbps 4-PAM data signal is directly modulated on a single mode 10 GHz bandwidth VCSEL carrier at 1310 nm, therefore, doubling the network bit rate. Carrier spectral efficiency is further maximized by modulating its phase attribute with a 2 GHz reference frequency (RF) clock signal. We, therefore, simultaneously transmit a 20 Gbps 4-PAM data signal and a phase modulated 2 GHz RF signal using a single mode 10 GHz bandwidth VCSEL carrier. It is the first time a single mode 10 GHz bandwidth VCSEL carrier is reported to simultaneously transmit a directly modulated 4-PAM data signal and a phase modulated RF clock signal. A receiver sensitivity of -10. 52 dBm was attained for a 20 Gbps 4-PAM VCSEL transmission. The 2 GHz phase modulated RF clock signal introduced a power budget penalty of 0.21 dB. Simultaneous distribution of both data and timing signals over shared infrastructure significantly increases the aggregated data rate at different optical network units within the DCN, without expensive optics investment. We further demonstrate on the design of a software-defined digital signal processing assisted receiver to efficiently recover the transmitted signal without employing costly receiver hardware.

Uncertainties in cloud phase and optical thickness retrievals from the Earth Polychromatic Imaging Camera (EPIC)

NASA Astrophysics Data System (ADS)

Meyer, Kerry; Yang, Yuekui; Platnick, Steven

2016-04-01

This paper presents an investigation of the expected uncertainties of a single-channel cloud optical thickness (COT) retrieval technique, as well as a simple cloud-temperature-threshold-based thermodynamic phase approach, in support of the Deep Space Climate Observatory (DSCOVR) mission. DSCOVR cloud products will be derived from Earth Polychromatic Imaging Camera (EPIC) observations in the ultraviolet and visible spectra. Since EPIC is not equipped with a spectral channel in the shortwave or mid-wave infrared that is sensitive to cloud effective radius (CER), COT will be inferred from a single visible channel with the assumption of appropriate CER values for liquid and ice phase clouds. One month of Aqua MODerate-resolution Imaging Spectroradiometer (MODIS) daytime granules from April 2005 is selected for investigating cloud phase sensitivity, and a subset of these granules that has similar EPIC Sun-view geometry is selected for investigating COT uncertainties. EPIC COT retrievals are simulated with the same algorithm as the operational MODIS cloud products (MOD06), except using fixed phase-dependent CER values. Uncertainty estimates are derived by comparing the single-channel COT retrievals with the baseline bi-spectral MODIS retrievals. Results show that a single-channel COT retrieval is feasible for EPIC. For ice clouds, single-channel retrieval errors are minimal (< 2 %) due to the particle size insensitivity of the assumed ice crystal (i.e., severely roughened aggregate of hexagonal columns) scattering properties at visible wavelengths, while for liquid clouds the error is mostly limited to within 10 %, although for thin clouds (COT < 2) the error can be higher. Potential uncertainties in EPIC cloud masking and cloud temperature retrievals are not considered in this study.

High-speed single-pixel digital holography

NASA Astrophysics Data System (ADS)

González, Humberto; Martínez-León, Lluís.; Soldevila, Fernando; Araiza-Esquivel, Ma.; Tajahuerce, Enrique; Lancis, Jesús

2017-06-01

The complete phase and amplitude information of biological specimens can be easily determined by phase-shifting digital holography. Spatial light modulators (SLMs) based on liquid crystal technology, with a frame-rate around 60 Hz, have been employed in digital holography. In contrast, digital micro-mirror devices (DMDs) can reach frame rates up to 22 kHz. A method proposed by Lee to design computer generated holograms (CGHs) permits the use of such binary amplitude modulators as phase-modulation devices. Single-pixel imaging techniques record images by sampling the object with a sequence of micro-structured light patterns and using a simple photodetector. Our group has reported some approaches combining single-pixel imaging and phase-shifting digital holography. In this communication, we review these techniques and present the possibility of a high-speed single-pixel phase-shifting digital holography system with phase-encoded illumination. This system is based on a Mach-Zehnder interferometer, with a DMD acting as the modulator for projecting the sampling patterns on the object and also being used for phase-shifting. The proposed sampling functions are phaseencoded Hadamard patterns generated through a Lee hologram approach. The method allows the recording of the complex amplitude distribution of an object at high speed on account of the high frame rates of the DMD. Reconstruction may take just a few seconds. Besides, the optical setup is envisaged as a true adaptive system, which is able to measure the aberration induced by the optical system in the absence of a sample object, and then to compensate the wavefront in the phasemodulation stage.

46 CFR 111.50-5 - Location of overcurrent protective devices.

Code of Federal Regulations, 2014 CFR

2014-10-01

... primary side of a single phase transformer (two wire with single-voltage secondary) also protects the... secondary conductor by the secondary to primary transformer voltage ratio, and this protection meets § 111...

46 CFR 111.50-5 - Location of overcurrent protective devices.

Code of Federal Regulations, 2011 CFR

2011-10-01

... primary side of a single phase transformer (two wire with single-voltage secondary) also protects the... secondary conductor by the secondary to primary transformer voltage ratio, and this protection meets § 111...

46 CFR 111.50-5 - Location of overcurrent protective devices.

Code of Federal Regulations, 2010 CFR

2010-10-01

... primary side of a single phase transformer (two wire with single-voltage secondary) also protects the... secondary conductor by the secondary to primary transformer voltage ratio, and this protection meets § 111...

46 CFR 111.50-5 - Location of overcurrent protective devices.

Code of Federal Regulations, 2013 CFR

2013-10-01

... primary side of a single phase transformer (two wire with single-voltage secondary) also protects the... secondary conductor by the secondary to primary transformer voltage ratio, and this protection meets § 111...

46 CFR 111.50-5 - Location of overcurrent protective devices.

Code of Federal Regulations, 2012 CFR

2012-10-01

... primary side of a single phase transformer (two wire with single-voltage secondary) also protects the... secondary conductor by the secondary to primary transformer voltage ratio, and this protection meets § 111...

Generation and the role of dislocations in single-crystalline phase-change In 2 Se 3 nanowires under electrical pulses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mafi, Elham; Tao, Xin; Zhu, Wenguang

2016-07-08

Using single crystalline In2Se3 nanowires as a platform, we have studied the RESET switching (from low to high electrical resistance) in this phase-change material under electric pulses. Particularly, we correlated the atomic-scale structural evolutions with local electrical resistance variations, by performing transmission electron microscopy and scanning Kelvin probe microscopy on the same nanowires. By coupling the experimental results with density functional theory calculations, we show that the immobile dislocations generated via vacancy condensations are responsible for the RESET switching and that the material maintains the single crystallinity during the process. This new mechanism is fundamentally different from the crystalline-amorphous transition,more » which is commonly understood as the underlying process for the RESET switching in similar phase-change materials.« less

Synthesis of formamidinium lead iodide perovskite bulk single crystal and its optical properties

NASA Astrophysics Data System (ADS)

Zheng, Hongge; Duan, Junjie; Dai, Jun

2017-07-01

Formamidinium lead iodide (FAPbI3) is a promising hybrid perovskite material for optoelectronic devices. We synthesized bulk single crystal FAPbI3 by a rapid solution crystallization method. X-ray diffraction (XRD) was performed to characterize the crystal structure. Temperature-dependent photoluminescence (PL) spectra of the bulk single crystal FAPbI3 were measured from 10 to 300 K to explain PL recombination mechanism. It shows that near band edge emission blueshifts with the temperature increasing from 10 to 120 K and from 140 K to room temperature, a sudden emission band redshift demonstrates near 140 K because of the phase transition from orthorhombic phase to cubic phase. From the temperature-dependent PL spectra, the temperature coefficients of the bandgap and thermal activation energies of FAPbI3 perovskite are fitted.

Computer Aided Design of Ni-Based Single Crystal Superalloy for Industrial Gas Turbine Blades

NASA Astrophysics Data System (ADS)

Wei, Xianping; Gong, Xiufang; Yang, Gongxian; Wang, Haiwei; Li, Haisong; Chen, Xueda; Gao, Zhenhuan; Xu, Yongfeng; Yang, Ming

The influence of molybdenum, tungsten and cobalt on stress-rupture properties of single crystal superalloy PWA1483 has been investigated using the simulated calculation of JMatPro software which ha s been widely used to develop single crystal superalloy, and the effect of alloying element on the stability of strengthening phase has been revealed by using the Thermo-Calc software. Those properties calculation results showed that the increasing of alloy content could facilitate the precipitation of TCP phases and increase the lattice misfit between γ and γ' phase, and the effect of molybdenum, tantalum was the strongest and that of cobalt was the weakest. Then the chemical composition was optimized, and the selected compositions showed excellent microstructure stability and stress-rupture properties by the confirmation of d-electrons concept and software calculation.

Shadow mechanism and the opposition effect of brightness of atmosphereless celestial bodies

NASA Astrophysics Data System (ADS)

Morozhenko, A. V.; Vidmachenko, A. P.

2013-09-01

We consider the Irvine-Yanovistkii modification of the shadow model developed by Hapke for the opposition effect of brightness. The relation between the single scattering albedo ω and the transparency coefficient of particles κ is suggested to be used in the form κ = (1 - ω) n, which allows the number of unknowns in the model to be reduced to two parameters (the packing density of particles g and ω) and the single-scattering phase function Ξ(α). The analysis of spectrophotometric measurements of the moon and Mars showed that the data on the observed opposition effect and the changes in the color index with the phase angle α well agree if the values of n = 0.25 and g = 0.4 (the moon) and 0.6 (Mars) are assumed in calculations. When being applied to asteroids of several types, this method also yielded a satisfactory agreement. For the E-type asteroids, the sets of parameters are [g = 0.6, ω = 0.6, A g = 0.21, and q = 0.83] or [g = 0.3, ω = 0.4, A g = 0.15, and q = 0.71] under the Martian single-scattering phase function; for the M-type asteroids, it is [g = 0.4, ω ≤ 0.1, A g ≤ 0.075, and q ≤ 0.42] under the lunar single-scattering phase function; for the S-type asteroids, it is [g = 0.4, ω = 0.4, A g = 0.28, and q = 0.49] under the lunar single-scattering phase function; and for the C-type asteroids, it is [g = 0.6, ω ≤ 0.1, A g ≤ 0.075, and q = 0.43] under the modified lunar single-scattering phase function. The polarization measurements fulfilled by Gehrels et al. (1964) for the bright feature on the lunar surface, Copernicus (L = -20°08', φ = +10°11'), at a phase angle α = 1.6° revealed the deviations in the position of the polarization plane from that typical for the negative branch. They were 22° and 12° in the G and I filters, respectively. At the same time, the deviation was within the error (±3° in the U filter and for the dark feature Plato (L = -10°32', φ = +51°25'), which can be caused by the coherent mechanism of the formation of the polarization peak.

Solid-phase single molecule biosensing using dual-color colocalization of fluorescent quantum dot nanoprobes

NASA Astrophysics Data System (ADS)

Liu, Jianbo; Yang, Xiaohai; Wang, Kemin; Wang, Qing; Liu, Wei; Wang, Dong

2013-10-01

The development of solid-phase surface-based single molecule imaging technology has attracted significant interest during the past decades. Here we demonstrate a sandwich hybridization method for highly sensitive detection of a single thrombin protein at a solid-phase surface based on the use of dual-color colocalization of fluorescent quantum dot (QD) nanoprobes. Green QD560-modified thrombin binding aptamer I (QD560-TBA I) were deposited on a positive poly(l-lysine) assembled layer, followed by bovine serum albumin blocking. It allowed the thrombin protein to mediate the binding of the easily detectable red QD650-modified thrombin binding aptamer II (QD650-TBA II) to the QD560-TBA I substrate. Thus, the presence of the target thrombin can be determined based on fluorescent colocalization measurements of the nanoassemblies, without target amplification or probe separation. The detection limit of this assay reached 0.8 pM. This fluorescent colocalization assay has enabled single molecule recognition in a separation-free detection format, and can serve as a sensitive biosensing platform that greatly suppresses the nonspecific adsorption false-positive signal. This method can be extended to other areas such as multiplexed immunoassay, single cell analysis, and real time biomolecule interaction studies.The development of solid-phase surface-based single molecule imaging technology has attracted significant interest during the past decades. Here we demonstrate a sandwich hybridization method for highly sensitive detection of a single thrombin protein at a solid-phase surface based on the use of dual-color colocalization of fluorescent quantum dot (QD) nanoprobes. Green QD560-modified thrombin binding aptamer I (QD560-TBA I) were deposited on a positive poly(l-lysine) assembled layer, followed by bovine serum albumin blocking. It allowed the thrombin protein to mediate the binding of the easily detectable red QD650-modified thrombin binding aptamer II (QD650-TBA II) to the QD560-TBA I substrate. Thus, the presence of the target thrombin can be determined based on fluorescent colocalization measurements of the nanoassemblies, without target amplification or probe separation. The detection limit of this assay reached 0.8 pM. This fluorescent colocalization assay has enabled single molecule recognition in a separation-free detection format, and can serve as a sensitive biosensing platform that greatly suppresses the nonspecific adsorption false-positive signal. This method can be extended to other areas such as multiplexed immunoassay, single cell analysis, and real time biomolecule interaction studies. Electronic supplementary information (ESI) available: Absorbance and fluorescence spectra of quantum dot nanoprobes, electrophoresis analysis, and experimental setup for fluorescence imaging with dual channels. See DOI: 10.1039/c3nr03291d

PI and repetitive control for single phase inverter based on virtual rotating coordinate system

NASA Astrophysics Data System (ADS)

Li, Mengqi; Tong, Yibin; Jiang, Jiuchun; Liang, Jiangang

2018-03-01

Microgrid technology developed rapidly and nonlinear loads were connected increasingly. A new control strategy was proposed for single phase inverter when connected nonlinear loads under island condition. PI and repetitive compound controller was realized under synchronous rotating coordinate system and acquired high quality sinusoidal voltage output without voltage spike when loads step changed. Validity and correctness were verified by simulation using MATLAB/Simulink.

Chirality-Controlled Growth of Single-Wall Carbon Nanotubes Using Vapor Phase Epitaxy: Mechanistic Understanding and Scalable Production

DTIC Science & Technology

2016-09-15

controlled synthesis of single-wall carbon nanotubes. Firstly, we have successfully demonstrated a vapor-phase-epitaxy-analogous general strategy for...preselected chirality. Moreover, we carried out systematic investigations of the chirality-dependent growth kinetics and termination mechanism for the... generally believed that the diameters of the nanotubes are determined by the size of the catalytic metal particles. Unfortunately, attempts to control

Phase transition in a multiferroic Ni-Mn-Ga single crystal

NASA Astrophysics Data System (ADS)

Veřtát, P.; Drahokoupil, J.; Perevertov, O.; Heczko, O.

2016-08-01

We studied martensitic phase transformation, crystal structure and twinned microstructure of resulting martensite of a Ni-Mn-Ga single crystal as essential conditions for magnetic shape memory effect. Thermal dependence of electric resistivity, magnetic susceptibility and dilatation measurements were measured to characterise kinetics of the transformation. With the help of XRD analysis and optical microscopy we evaluated the hierarchical twinning microstructure in the 10M martensite.

Parity-time–symmetric optoelectronic oscillator

PubMed Central

2018-01-01

An optoelectronic oscillator (OEO) is a hybrid microwave and photonic system incorporating an amplified positive feedback loop to enable microwave oscillation to generate a high-frequency and low–phase noise microwave signal. The low phase noise is ensured by the high Q factor of the feedback loop enabled by the use of a long and low-loss optical fiber. However, an OEO with a long fiber loop would have a small free spectral range, leading to a large number of closely spaced oscillation modes. To ensure single-mode oscillation, an ultranarrowband optical filter must be used, but such an optical filter is hard to implement and the stability is poor. Here, we use a novel concept to achieve single-mode oscillation without using an ultranarrowband optical filter. The single-mode operation is achieved based on parity-time (PT) symmetry by using two identical feedback loops, with one having a gain and the other having a loss of the same magnitude. The operation is analyzed theoretically and verified by an experiment. Stable single-mode oscillation at an ultralow phase noise is achieved without the use of an ultranarrowband optical filter. The use of PT symmetry in an OEO overcomes the long-existing mode-selection challenge that would greatly simplify the implementation of OEOs for ultralow–phase noise microwave generation. PMID:29888325

Substrate-induced phase of a [1]benzothieno[3,2-b]benzothiophene derivative and phase evolution by aging and solvent vapor annealing.

PubMed

Jones, Andrew O F; Geerts, Yves H; Karpinska, Jolanta; Kennedy, Alan R; Resel, Roland; Röthel, Christian; Ruzié, Christian; Werzer, Oliver; Sferrazza, Michele

2015-01-28

Substrate-induced phases (SIPs) are polymorphic phases that are found in thin films of a material and are different from the single crystal or "bulk" structure of a material. In this work, we investigate the presence of a SIP in the family of [1]benzothieno[3,2-b]benzothiophene (BTBT) organic semiconductors and the effect of aging and solvent vapor annealing on the film structure. Through extensive X-ray structural investigations of spin coated films, we find a SIP with a significantly different structure to that found in single crystals of the same material forms; the SIP has a herringbone motif while single crystals display layered π-π stacking. Over time, the structure of the film is found to slowly convert to the single crystal structure. Solvent vapor annealing initiates the same structural evolution process but at a greatly increased rate, and near complete conversion can be achieved in a short period of time. As properties such as charge transport capability are determined by the molecular structure, this work highlights the importance of understanding and controlling the structure of organic semiconductor films and presents a simple method to control the film structure by solvent vapor annealing.

Single-shot water-immersion microscopy platform for qualitative visualization and quantitative phase imaging of biosamples

NASA Astrophysics Data System (ADS)

Picazo-Bueno, José Ángel; Cojoc, Dan; Torre, Vincent; Micó, Vicente

2017-07-01

We present the combination of a single-shot water-immersion digital holographic microscopy with broadband illumination for simultaneous visualization of coherent and incoherent images using microbeads and different biosamples.

76 FR 67200 - Prospective Grant of Exclusive License: Electron Paramagnetic Resonance Devices and Systems for...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-31

... that is a unique combination of: (1) multi-gradient Single Point Imaging involving global phase...-encoding gradients. The combination approach of single point imaging with the spin-echo signal detection...

Multimode excitation-induced phase shifts in intrinsic Fabry-Perot interferometric fiber sensor spectra.

PubMed

Ma, Cheng; Wang, Anbo

2010-09-01

We report the modal analysis of optical fiber single-mode-multimode-single-mode intrinsic Fabry-Perot interferometer sensors. The multimode nature of the Fabry-Perot cavity gives rise to an additional phase term in the spectrogram due to intermodal dispersion-induced wavefront distortion, which could significantly affect the cavity length demodulation accuracy. By using an exact model to analyze the modal behavior, this phase term is explained by employing a rotating vector approach. Comparison of the theoretical analysis with experimental results is presented.

Field-induced phase transition in Ce3M4Sn13 with M = Co, Rh, and Ru

NASA Astrophysics Data System (ADS)

Ślebarski, Andrzej; Goraus, Jerzy

2018-05-01

Large electronic specific heat coefficient, C (T) / T , suggests that the family of Ce3M4Sn13 heavy-fermions (HF) is near a magnetic quantum critical point (QCP). We analyze the 4 f contribution to the specific heat in terms of the single-ion Kondo resonance model. An unexpected change in the Kondo temperature TK versus magnetic field B signals a field-induced phase transition between the magnetically correlated HF phase and a single-ion Kondo impurity state.

Determining single-ion and spatial exchange anisotropies by pulsed-field magnetometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Manson, J. L.; Villa, J. A.; Singleton, John

2017-02-13

The magnetic ground-state of the Q1D S = 1 antiferromagnetic (AFM) chain is sensitive to the single-ion anisotropy (D) and the relative strength of intra- (J) and interchain (J’) exchange interactions. The ratios D/J and J’/J dictate the material’s placement on the phase diagram for which three competing phases are known to theoretically exist: Haldane, XY and quantum paramagnetic. We identified [Ni(HF 2)(pyz) 2]SbF 6 (pyz = pyrazine) as a candidate in which to explore proximity to these phases.

Advanced Transformer Demonstration and Validation Project Summary Report Based on Experiences at NAS, North Island, San Diego, California

DTIC Science & Technology

1992-08-01

three existing 167 kVA PCB-filled, single phase , polemount transformers that were connected in a three phase bank and replacing them with a single 300...A-18 3.11.1 Insulated Phase Barriers .......................... A-lB 3.11.2 Undercoating ...................................... A-18 3.11.3 Warning...2.1 mezan Na, ý n al S I.and a r, 7nSt *u~e f’-^S. ANSI- C57 12.00 General Requirements for Liquid Immersed Distribution Power and Regulating

Advanced Transformer Demonstration And Validation Project Summary Report Based On Experiences At Nas, North Island, San Diego. California

DTIC Science & Technology

1992-08-01

MAXIMIUI• 0 P 8. ALL LIGHTS ARE LED"’ TORMAD TEM"ERATUE TO RESET 9. DIGITAL METER IS LE[in EMORY IETER WILL AUTOMATICALLY MAD PHASE WiTH HIGHEST...in place. 4.4 Building 379 The Building 379 installation consisted of removing three existing 167 kVA PCB-filled, single phase , polemount transformers...that were connected in a three phase bank and replacing them with a single 300 kVA Square D Company VPI dry-type transformer. This task also involved

Amount of fear extinction changes its underlying mechanisms.

PubMed

An, Bobae; Kim, Jihye; Park, Kyungjoon; Lee, Sukwon; Song, Sukwoon; Choi, Sukwoo

2017-07-03

There has been a longstanding debate on whether original fear memory is inhibited or erased after extinction. One possibility that reconciles this uncertainty is that the inhibition and erasure mechanisms are engaged in different phases (early or late) of extinction. In this study, using single-session extinction training and its repetition (multiple-session extinction training), we investigated the inhibition and erasure mechanisms in the prefrontal cortex and amygdala of rats, where neural circuits underlying extinction reside. The inhibition mechanism was prevalent with single-session extinction training but faded when single-session extinction training was repeated. In contrast, the erasure mechanism became prevalent when single-session extinction training was repeated. Moreover, ablating the intercalated neurons of amygdala, which are responsible for maintaining extinction-induced inhibition, was no longer effective in multiple-session extinction training. We propose that the inhibition mechanism operates primarily in the early phase of extinction training, and the erasure mechanism takes over after that.

Transmission electron microscopy study of the formation of epitaxial CoSi2/Si (111) by a room-temperature codeposition technique

NASA Technical Reports Server (NTRS)

D'Anterroches, Cecile; Yakupoglu, H. Nejat; Lin, T. L.; Fathauer, R. W.; Grunthaner, P. J.

1988-01-01

Co and Si have been codeposited on Si (111) substrates near room temperature in a stoichiometric 1:2 ratio in a molecular beam epitaxy system. Annealing of these deposits yields high-quality single-crystal CoSi2 layers. Transmission electron microscopy has been used to examine as-deposited layers and layers annealed at 300, 500, and 600 C. Single-crystal epitaxial grains of CoSi2 embedded in a matrix of amorphous Co/Si are observed in as-deposited samples, while the layer is predominantly single-crystal, inhomogeneously strained CoSi2 at 300 C. At 600 C, a homogeneously strained single-crystal layer with a high density of pinholes is observed. In contrast to other solid phase epitaxy techniques used to grow CoSi2 on Si (111), no intermediate silicide phases are observed prior to the formation of CoSi2.

Dynamics of lineage commitment revealed by single-cell transcriptomics of differentiating embryonic stem cells.

PubMed

Semrau, Stefan; Goldmann, Johanna E; Soumillon, Magali; Mikkelsen, Tarjei S; Jaenisch, Rudolf; van Oudenaarden, Alexander

2017-10-23

Gene expression heterogeneity in the pluripotent state of mouse embryonic stem cells (mESCs) has been increasingly well-characterized. In contrast, exit from pluripotency and lineage commitment have not been studied systematically at the single-cell level. Here we measure the gene expression dynamics of retinoic acid driven mESC differentiation from pluripotency to lineage commitment, using an unbiased single-cell transcriptomics approach. We find that the exit from pluripotency marks the start of a lineage transition as well as a transient phase of increased susceptibility to lineage specifying signals. Our study reveals several transcriptional signatures of this phase, including a sharp increase of gene expression variability and sequential expression of two classes of transcriptional regulators. In summary, we provide a comprehensive analysis of the exit from pluripotency and lineage commitment at the single cell level, a potential stepping stone to improved lineage manipulation through timing of differentiation cues.

Guidelines for the formulation of Lagrangian stochastic models for particle simulations of single-phase and dispersed two-phase turbulent flows

NASA Astrophysics Data System (ADS)

Minier, Jean-Pierre; Chibbaro, Sergio; Pope, Stephen B.

2014-11-01

In this paper, we establish a set of criteria which are applied to discuss various formulations under which Lagrangian stochastic models can be found. These models are used for the simulation of fluid particles in single-phase turbulence as well as for the fluid seen by discrete particles in dispersed turbulent two-phase flows. The purpose of the present work is to provide guidelines, useful for experts and non-experts alike, which are shown to be helpful to clarify issues related to the form of Lagrangian stochastic models. A central issue is to put forward reliable requirements which must be met by Lagrangian stochastic models and a new element brought by the present analysis is to address the single- and two-phase flow situations from a unified point of view. For that purpose, we consider first the single-phase flow case and check whether models are fully consistent with the structure of the Reynolds-stress models. In the two-phase flow situation, coming up with clear-cut criteria is more difficult and the present choice is to require that the single-phase situation be well-retrieved in the fluid-limit case, elementary predictive abilities be respected and that some simple statistical features of homogeneous fluid turbulence be correctly reproduced. This analysis does not address the question of the relative predictive capacities of different models but concentrates on their formulation since advantages and disadvantages of different formulations are not always clear. Indeed, hidden in the changes from one structure to another are some possible pitfalls which can lead to flaws in the construction of practical models and to physically unsound numerical calculations. A first interest of the present approach is illustrated by considering some models proposed in the literature and by showing that these criteria help to assess whether these Lagrangian stochastic models can be regarded as acceptable descriptions. A second interest is to indicate how future developments can be safely built, which is also relevant for stochastic subgrid models for particle-laden flows in the context of Large Eddy Simulations.

Guidelines for the formulation of Lagrangian stochastic models for particle simulations of single-phase and dispersed two-phase turbulent flows

DOE Office of Scientific and Technical Information (OSTI.GOV)

Minier, Jean-Pierre, E-mail: Jean-Pierre.Minier@edf.fr; Chibbaro, Sergio; Pope, Stephen B.

In this paper, we establish a set of criteria which are applied to discuss various formulations under which Lagrangian stochastic models can be found. These models are used for the simulation of fluid particles in single-phase turbulence as well as for the fluid seen by discrete particles in dispersed turbulent two-phase flows. The purpose of the present work is to provide guidelines, useful for experts and non-experts alike, which are shown to be helpful to clarify issues related to the form of Lagrangian stochastic models. A central issue is to put forward reliable requirements which must be met by Lagrangianmore » stochastic models and a new element brought by the present analysis is to address the single- and two-phase flow situations from a unified point of view. For that purpose, we consider first the single-phase flow case and check whether models are fully consistent with the structure of the Reynolds-stress models. In the two-phase flow situation, coming up with clear-cut criteria is more difficult and the present choice is to require that the single-phase situation be well-retrieved in the fluid-limit case, elementary predictive abilities be respected and that some simple statistical features of homogeneous fluid turbulence be correctly reproduced. This analysis does not address the question of the relative predictive capacities of different models but concentrates on their formulation since advantages and disadvantages of different formulations are not always clear. Indeed, hidden in the changes from one structure to another are some possible pitfalls which can lead to flaws in the construction of practical models and to physically unsound numerical calculations. A first interest of the present approach is illustrated by considering some models proposed in the literature and by showing that these criteria help to assess whether these Lagrangian stochastic models can be regarded as acceptable descriptions. A second interest is to indicate how future developments can be safely built, which is also relevant for stochastic subgrid models for particle-laden flows in the context of Large Eddy Simulations.« less

Temperature induced phase transformations and negative electrocaloric effect in (Pb,La)(Zr,Sn,Ti)O3 antiferroelectric single crystal

NASA Astrophysics Data System (ADS)

Zhuo, Fangping; Li, Qiang; Yan, Qingfeng; Zhang, Yiling; Wu, Hong-Hui; Xi, Xiaoqing; Chu, Xiangcheng; Cao, Wenwu

2017-10-01

Temperature induced phase transitions and electrocaloric effect (ECE) of (Pb,La)(Zr,Sn,Ti)O3 (PLZST) single crystals have been comprehensively studied. Based on the in situ evolution of domain structures and dielectric properties of the PLZST crystals, the phase transitions during heating are in the sequence of orthorhombic antiferroelectric → rhombohedral ferroelectric → cubic paraelectric. Coexistence of the negative and positive ECEs has been achieved in the PLZST single crystals. A negative ECE value of -1.26 °C and enhanced electrocaloric strength of -0.21 K mm/kV near the Curie temperature have been obtained. A modified Landau model gives a satisfactory description of the experimentally observed unusual ECE. Moreover, a temperature-electric field phase diagram is also established based on theoretical analysis. Our results will help people understand better the electrocaloric family, particularly on the negative and/or positive effect in antiferroelectrics and ferroelectrics.

An equivalent dipole analysis of PZT ceramics and lead-free piezoelectric single crystals

NASA Astrophysics Data System (ADS)

Bell, Andrew J.

2016-04-01

The recently proposed Equivalent Dipole Model for describing the electromechanical properties of ionic solids in terms of 3 ions and 2 bonds has been applied to PZT ceramics and lead-free single crystal piezoelectric materials, providing analysis in terms of an effective ionic charge and the asymmetry of the interatomic force constants. For PZT it is shown that, as a function of composition across the morphotropic phase boundary, the dominant bond compliance peaks at 52% ZrO2. The stiffer of the two bonds shows little composition dependence with no anomaly at the phase boundary. The effective charge has a maximum value at 50% ZrO2, decreasing across the phase boundary region, but becoming constant in the rhombohedral phase. The single crystals confirm that both the asymmetry in the force constants and the magnitude of effective charge are equally important in determining the values of the piezoelectric charge coefficient and the electromechanical coupling coefficient. Both are apparently temperature dependent, increasing markedly on approaching the Curie temperature.

The effectiveness of environmental strategies on noise reduction in a pediatric intensive care unit: creation of single-patient bedrooms and reducing noise sources.

PubMed

Kol, Emine; Aydın, Perihan; Dursun, Oguz

2015-07-01

Noise is a substantial problem for both patients and healthcare workers in hospitals. This study aimed to determine the effectiveness of environmental strategies (creating single-patient rooms and reducing noise sources) in noise reduction in a pediatric intensive care unit. Noise measurement in the unit was conducted in two phases. In the first phase, measurements aimed at determining the unit's present level of noise were performed over 4 weeks in December 2013. During the month following the first measurement phase, the intensive care unit (ICU) was moved to a new location and noise-reducing strategies were implemented. The second phase, in May 2014, measured noise levels in the newly constructed environment. The noise levels before and after environmental changes were statistically significant at 72.6 dB-A and 56 dB-A, respectively (p < .05). Single-patient rooms and noise-reducing strategies can be effective in controlling environmental noise in the ICU. © 2015, Wiley Periodicals, Inc.

Optical properties of single and bilayer arsenene phases

NASA Astrophysics Data System (ADS)

Kecik, Deniz; Ciraci, Salim; Durgun, Engin

An extensive investigation of the optical properties of single-layer buckled and washboard arsenene and their bilayers was performed, starting from layered three-dimensional (3D) crystalline phase of arsenic using density functional and many-body perturbation theories combined with Random Phase Approximation. Electron-hole interactions were taken into account by solving the Bethe-Salpeter equation, suggesting first bound exciton energies on the order of 0.7 eV. Thus, many-body effects were found to be crucial for altering the optical properties of arsenene. The light absorption of single layer and bilayer arsenene structures in general falls within the visible-ultraviolet (UV) spectral regime. Moreover, directional anisotropy, varying the number of layers and applying homogeneous or uniaxial in-plane tensile strain were found to modify the optical properties of two-dimensional (2D) arsenene phases, which could be useful for diverse photovoltaic and optoelectronic applications. This work was supported by the Scientific and Technological Research Council of Turkey (TUBITAK) under Project No 115F088.

Quantitative x-ray phase-contrast imaging using a single grating of comparable pitch to sample feature size.

PubMed

Morgan, Kaye S; Paganin, David M; Siu, Karen K W

2011-01-01

The ability to quantitatively retrieve transverse phase maps during imaging by using coherent x rays often requires a precise grating or analyzer-crystal-based setup. Imaging of live animals presents further challenges when these methods require multiple exposures for image reconstruction. We present a simple method of single-exposure, single-grating quantitative phase contrast for a regime in which the grating period is much greater than the effective pixel size. A grating is used to create a high-visibility reference pattern incident on the sample, which is distorted according to the complex refractive index and thickness of the sample. The resolution, along a line parallel to the grating, is not restricted by the grating spacing, and the detector resolution becomes the primary determinant of the spatial resolution. We present a method of analysis that maps the displacement of interrogation windows in order to retrieve a quantitative phase map. Application of this analysis to the imaging of known phantoms shows excellent correspondence.

In Situ Observation of Single-Phase Lithium Intercalation in Sub-25-nm Nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhong, Li; Liu, Yang; Han, Wei-Qiang

Although a non-equilibrium single-phase reaction, with the absence of nucleation and growth of a second phase, is believed to be a key factor for high-rate performance of lithium-ion batteries, it is thermodynamically unfavorable and usually proceeds in electrode materials with small particle sizes (tens of nanometers). Unfortunately, the phase evolutions inside such small particles are often shrouded by the macroscopic inhomogeneous reactions of electrodes containing millions of particles, leading to intensive debate over the size-dependent microscopic reaction mechanisms. Here, we provide a generally applicable methodology based on in-situ electron diffraction study on a multi-particle system to track the lithiation pathwaysmore » in individual nanoparticles, and unambiguously reveal that lithiation of anatase TiO 2, previously long believed to be biphasic, converts to a single-phase reaction when the particle size is below ~25 nm. Our results imply the prevalence of such a size-dependent transition in lithiation mechanism among intercalation compounds whose lithium miscibility gaps are associated with a prominent size effect, and therefore provide important guidelines for designing high-power electrodes, especially cathodes.« less

X-ray diffraction tomography of polycrystalline materials: present and future (Conference Presentation)

NASA Astrophysics Data System (ADS)

Stock, Stuart R.; Almer, Jonathan D.; Birkedal, Henrik

2016-10-01

Scattered x-radiation can be used for computed tomographic reconstruction of the distribution of crystallographic phases within the interior of specimens, and diffraction patterns can be measured for each volume element (voxel) within a reconstructed slice. This modality has been applied to systems as diverse as mineralized tissues and inorganic composites. Use of high energy x-rays (E < 40 keV) offers advantages including the ability to study volumes deep with specimens and to sample large ranges of reciprocal space, i.e., many reflections. The bases of diffraction tomography are reviewed, and the power of the technique is illustrated by the results obtained for specimens containing: a) different materials (SiC/Al composite), b) different polytypes (calcite/aragonite in a bivalve attachment system); c) mixtures of nanocrystalline and amorphous phases; d) a single phase, but volumes with different lattice parameters (hydroxyapatite, hAp, the mineral in bone and tooth); e) a single phase containing a spatial distribution of crystallographic texture (bone); a single phase with a spatial distribution of strains produced by in situ loading (bone). Finally, challenges and future directions are discussed.

In Situ Observation of Single-Phase Lithium Intercalation in Sub-25-nm Nanoparticles

DOE PAGES

Zhong, Li; Liu, Yang; Han, Wei-Qiang; ...

2017-05-05

Although a non-equilibrium single-phase reaction, with the absence of nucleation and growth of a second phase, is believed to be a key factor for high-rate performance of lithium-ion batteries, it is thermodynamically unfavorable and usually proceeds in electrode materials with small particle sizes (tens of nanometers). Unfortunately, the phase evolutions inside such small particles are often shrouded by the macroscopic inhomogeneous reactions of electrodes containing millions of particles, leading to intensive debate over the size-dependent microscopic reaction mechanisms. Here, we provide a generally applicable methodology based on in-situ electron diffraction study on a multi-particle system to track the lithiation pathwaysmore » in individual nanoparticles, and unambiguously reveal that lithiation of anatase TiO 2, previously long believed to be biphasic, converts to a single-phase reaction when the particle size is below ~25 nm. Our results imply the prevalence of such a size-dependent transition in lithiation mechanism among intercalation compounds whose lithium miscibility gaps are associated with a prominent size effect, and therefore provide important guidelines for designing high-power electrodes, especially cathodes.« less

Coherently coupled high-power fiber arrays

NASA Astrophysics Data System (ADS)

Anderegg, Jesse; Brosnan, Stephen; Cheung, Eric; Epp, Paul; Hammons, Dennis; Komine, Hiroshi; Weber, Mark; Wickham, Michael

2006-02-01

A four-element fiber array has demonstrated 470 watts of coherently phased, linearly polarized light energy in a single far-field spot. Each element consists of a single-mode fiber-amplifier chain. Phase control of each element is achieved with a Lithium-Niobate phase modulator. A master laser provides a linearly polarized, narrow linewidth signal that is split into five channels. Four channels are individually amplified using polarization maintaining fiber power amplifiers. The fifth channel is used as a reference arm. It is frequency shifted and then combined interferometrically with a portion of each channel's signal. Detectors sense the heterodyne modulation signal, and an electronics circuit measures the relative phase for each channel. Compensating adjustments are then made to each channel's phase modulator. This effort represents the results of a multi-year effort to achieve high power from a single element fiber amplifier and to understand the important issues involved in coherently combining many individual elements to obtain sufficient optical power for directed energy weapons. Northrop Grumman Corporation and the High Energy Laser Joint Technology Office jointly sponsored this work.

Successive Phase Transitions and Magnetic Fluctuation in a Double-Perovskite NdBaMn2O6 Single Crystal

NASA Astrophysics Data System (ADS)

Yamada, S.; Sagayama, H.; Sugimoto, K.; Arima, T.

2018-03-01

We have succeeded in growing large high-quality single crystals of double-perovskite NdBaMn2O6 with c-axis aligned. Curie-Weiss paramagnetism and metallic conduction are observed above 290 K (TMI ). The magnetic susceptibility suddenly drops at TMI accompanied by a metal-insulator transition. Pervious studies using polycrystalline samples proposed that this material undergoes a ferromagnetic phase transition near 300K, and that the magnetic anomaly at TMI should be ascribed to layered antiferromagnetic phase transition. However, single-crystalline samples do not show any anomaly that indicates the ferromagnetic phase transition above TMI . We assign the onset of magnetic anisotropy at 235 K as antiferromagnetic transition temperature TN . Though the magnetization just above TMI shows the ferromagnetic-like magnetic-field dependence, the magnetization does not saturate under 70kOe at 300K. The magnetization behavior implies ferromagnetic fluctuation in the paramagnetic phase. The ferromagnetic fluctuation are also observed just below TMI . Because a metamagnetic transition is observed at a higher magnetic field, the ferromagnetic fluctuation competes with antiferromagnetic fluctuation in this temperature range.

Single-crystal diffraction instrument TriCS at SINQ

NASA Astrophysics Data System (ADS)

Schefer, J.; Könnecke, M.; Murasik, A.; Czopnik, A.; Strässle, Th; Keller, P.; Schlumpf, N.

2000-03-01

The single-crystal diffractometer TriCS at the Swiss Continuous Spallation Source (SINQ) is presently in the commissioning phase. A two-dimensional wire detector produced by EMBL was delivered in March 1999. The instrument is presently tested with a single detector. First measurements on magnetic structures have been performed. The instrument is remotely controlled using JAVA-based software and a UNIX DEC-α host computer.

Real time quantitative phase microscopy based on single-shot transport of intensity equation (ssTIE) method

NASA Astrophysics Data System (ADS)

Yu, Wei; Tian, Xiaolin; He, Xiaoliang; Song, Xiaojun; Xue, Liang; Liu, Cheng; Wang, Shouyu

2016-08-01

Microscopy based on transport of intensity equation provides quantitative phase distributions which opens another perspective for cellular observations. However, it requires multi-focal image capturing while mechanical and electrical scanning limits its real time capacity in sample detections. Here, in order to break through this restriction, real time quantitative phase microscopy based on single-shot transport of the intensity equation method is proposed. A programmed phase mask is designed to realize simultaneous multi-focal image recording without any scanning; thus, phase distributions can be quantitatively retrieved in real time. It is believed the proposed method can be potentially applied in various biological and medical applications, especially for live cell imaging.

Single-Cycle Terahertz Pulse Generation from OH1 Crystal via Cherenkov Phase Matching

NASA Astrophysics Data System (ADS)

Uchida, Hirohisa; Oota, Kengo; Okimura, Koutarou; Kawase, Kodo; Takeya, Kei

2018-06-01

OH1 crystal is an organic nonlinear optical crystal with a large nonlinear optical constant. However, it has dispersion of refractive indices in the terahertz (THz) frequency. This limits the frequencies that satisfy the phase matching conditions for THz wave generation. In this study, we addressed the phase matching conditions for THz wave generation by combining an OH1 crystal with prism-coupled Cherenkov phase matching. We observed the generation of single-cycle THz pulses with a spectrum covering a frequency range of 3 THz. These results prove that combining prism-coupled Cherenkov phase matching with nonlinear optical crystals yields a THz wave generation method that is insusceptible to crystal dispersion.

Single-Cycle Terahertz Pulse Generation from OH1 Crystal via Cherenkov Phase Matching

NASA Astrophysics Data System (ADS)

Uchida, Hirohisa; Oota, Kengo; Okimura, Koutarou; Kawase, Kodo; Takeya, Kei

2018-03-01

OH1 crystal is an organic nonlinear optical crystal with a large nonlinear optical constant. However, it has dispersion of refractive indices in the terahertz (THz) frequency. This limits the frequencies that satisfy the phase matching conditions for THz wave generation. In this study, we addressed the phase matching conditions for THz wave generation by combining an OH1 crystal with prism-coupled Cherenkov phase matching. We observed the generation of single-cycle THz pulses with a spectrum covering a frequency range of 3 THz. These results prove that combining prism-coupled Cherenkov phase matching with nonlinear optical crystals yields a THz wave generation method that is insusceptible to crystal dispersion.

Quaternion-valued single-phase model for three-phase power system

NASA Astrophysics Data System (ADS)

Gou, Xiaoming; Liu, Zhiwen; Liu, Wei; Xu, Yougen; Wang, Jiabin

2018-03-01

In this work, a quaternion-valued model is proposed in lieu of the Clarke's α, β transformation to convert three-phase quantities to a hypercomplex single-phase signal. The concatenated signal can be used for harmonic distortion detection in three-phase power systems. In particular, the proposed model maps all the harmonic frequencies into frequencies in the quaternion domain, while the Clarke's transformation-based methods will fail to detect the zero sequence voltages. Based on the quaternion-valued model, the Fourier transform, the minimum variance distortionless response (MVDR) algorithm and the multiple signal classification (MUSIC) algorithm are presented as examples to detect harmonic distortion. Simulations are provided to demonstrate the potentials of this new modeling method.

Single-reactor process for producing liquid-phase organic compounds from biomass

DOEpatents

Dumesic, James A.; Simonetti, Dante A.; Kunkes, Edward L.

2015-12-08

Disclosed is a method for preparing liquid fuel and chemical intermediates from biomass-derived oxygenated hydrocarbons. The method includes the steps of reacting in a single reactor an aqueous solution of a biomass-derived, water-soluble oxygenated hydrocarbon reactant, in the presence of a catalyst comprising a metal selected from the group consisting of Cr, Mn, Fe, Co, Ni, Cu, Mo, Tc, Ru, Rh, Pd, Ag, W, Re, Os, Ir, Pt, and Au, at a temperature, and a pressure, and for a time sufficient to yield a self-separating, three-phase product stream comprising a vapor phase, an organic phase containing linear and/or cyclic mono-oxygenated hydrocarbons, and an aqueous phase.

Single-reactor process for producing liquid-phase organic compounds from biomass

DOEpatents

Dumesic, James A [Verona, WI; Simonetti, Dante A [Middleton, WI; Kunkes, Edward L [Madison, WI

2011-12-13

Disclosed is a method for preparing liquid fuel and chemical intermediates from biomass-derived oxygenated hydrocarbons. The method includes the steps of reacting in a single reactor an aqueous solution of a biomass-derived, water-soluble oxygenated hydrocarbon reactant, in the presence of a catalyst comprising a metal selected from the group consisting of Cr, Mn, Fe, Co, Ni, Cu, Mo, Tc, Ru, Rh, Pd, Ag, W, Re, Os, Ir, Pt, and Au, at a temperature, and a pressure, and for a time sufficient to yield a self-separating, three-phase product stream comprising a vapor phase, an organic phase containing linear and/or cyclic mono-oxygenated hydrocarbons, and an aqueous phase.

Electrical heating of soils using high efficiency electrode patterns and power phases

DOEpatents

Buettner, Harley M.

1999-01-01

Powerline-frequency electrical (joule) heating of soils using a high efficiency electrode configuration and power phase arrangement. The electrode configuration consists of several heating or current injection electrodes around the periphery of a volume of soil to be heated, all electrodes being connected to one phase of a multi-phase or a single-phase power system, and a return or extraction electrode or electrodes located inside the volume to be heated being connected to the remaining phases of the multi-phase power system or to the neutral side of the single-phase power source. This electrode configuration and power phase arrangement can be utilized anywhere where powerline frequency soil heating is applicable and thus has many potential uses including removal of volatile organic compounds such as gasoline and tricholorethylene (TCE) from contaminated areas.

Temperature-phased anaerobic digestion of food waste: A comparison with single-stage digestions based on performance and energy balance.

PubMed

Xiao, Benyi; Qin, Yu; Zhang, Wenzhe; Wu, Jing; Qiang, Hong; Liu, Junxin; Li, Yu-You

2018-02-01

The temperature-phased anaerobic digestion (TPAD) of food waste was studied for the purpose of comparing with single-stage mesophilic and thermophilic anaerobic digestion. The biogas and methane yields in the TPAD during the steady period were 0.759 ± 0.115 L/g added VS and 0.454 ± 0.201 L/g added VS, which were lower than those in the two single-stage anaerobic digestion. The improper sludge retention time may be the reason for the lower biogas and methane production in TPAD. The removal of volatile solids in the TPAD was 78.55 ± 4.59% and the lowest among the three anaerobic digestion processes. The reaction ratios of the four anaerobic digestion steps in the TPAD were all lower than those in the two single-stage anaerobic digestion. The energy conversion efficiency of the degraded substrate in the TPAD was similar with those in single-stage mesophilic and thermophilic anaerobic digestion systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Using the Image Analysis Method for Describing Soil Detachment by a Single Water Drop Impact

PubMed Central

Ryżak, Magdalena; Bieganowski, Andrzej

2012-01-01

The aim of the present work was to develop a method based on image analysis for describing soil detachment caused by the impact of a single water drop. The method consisted of recording tracks made by splashed particles on blotting paper under an optical microscope. The analysis facilitated division of the recorded particle tracks on the paper into drops, “comets” and single particles. Additionally, the following relationships were determined: (i) the distances of splash; (ii) the surface areas of splash tracks into relation to distance; (iii) the surface areas of the solid phase transported over a given distance; and (iv) the ratio of the solid phase to the splash track area in relation to distance. Furthermore, the proposed method allowed estimation of the weight of soil transported by a single water drop splash in relation to the distance of the water drop impact. It was concluded that the method of image analysis of splashed particles facilitated analysing the results at very low water drop energy and generated by single water drops.

Simultaneous measurement of chromatin accessibility, DNA methylation, and nucleosome phasing in single cells

PubMed Central

Pott, Sebastian

2017-01-01

Gaining insights into the regulatory mechanisms that underlie the transcriptional variation observed between individual cells necessitates the development of methods that measure chromatin organization in single cells. Here I adapted Nucleosome Occupancy and Methylome-sequencing (NOMe-seq) to measure chromatin accessibility and endogenous DNA methylation in single cells (scNOMe-seq). scNOMe-seq recovered characteristic accessibility and DNA methylation patterns at DNase hypersensitive sites (DHSs). An advantage of scNOMe-seq is that sequencing reads are sampled independently of the accessibility measurement. scNOMe-seq therefore controlled for fragment loss, which enabled direct estimation of the fraction of accessible DHSs within individual cells. In addition, scNOMe-seq provided high resolution of chromatin accessibility within individual loci which was exploited to detect footprints of CTCF binding events and to estimate the average nucleosome phasing distances in single cells. scNOMe-seq is therefore well-suited to characterize the chromatin organization of single cells in heterogeneous cellular mixtures. DOI: http://dx.doi.org/10.7554/eLife.23203.001 PMID:28653622

Coherent diffractive imaging of single helium nanodroplets with a high harmonic generation source.

PubMed

Rupp, Daniela; Monserud, Nils; Langbehn, Bruno; Sauppe, Mario; Zimmermann, Julian; Ovcharenko, Yevheniy; Möller, Thomas; Frassetto, Fabio; Poletto, Luca; Trabattoni, Andrea; Calegari, Francesca; Nisoli, Mauro; Sander, Katharina; Peltz, Christian; J Vrakking, Marc; Fennel, Thomas; Rouzée, Arnaud

2017-09-08

Coherent diffractive imaging of individual free nanoparticles has opened routes for the in situ analysis of their transient structural, optical, and electronic properties. So far, single-shot single-particle diffraction was assumed to be feasible only at extreme ultraviolet and X-ray free-electron lasers, restricting this research field to large-scale facilities. Here we demonstrate single-shot imaging of isolated helium nanodroplets using extreme ultraviolet pulses from a femtosecond-laser-driven high harmonic source. We obtain bright wide-angle scattering patterns, that allow us to uniquely identify hitherto unresolved prolate shapes of superfluid helium droplets. Our results mark the advent of single-shot gas-phase nanoscopy with lab-based short-wavelength pulses and pave the way to ultrafast coherent diffractive imaging with phase-controlled multicolor fields and attosecond pulses.Diffraction imaging studies of free individual nanoparticles have so far been restricted to XUV and X-ray free - electron laser facilities. Here the authors demonstrate the possibility of using table-top XUV laser sources to image prolate shapes of superfluid helium droplets.

Landing mechanics during single hop for distance in females following anterior cruciate ligament reconstruction compared to healthy controls.

PubMed

Trigsted, Stephanie M; Post, Eric G; Bell, David R

2017-05-01

To determine possible differences in single-hop kinematics and kinetics in females with anterior cruciate ligament reconstruction compared to healthy controls. A second purpose was to make comparisons between the healthy and reconstructed limbs. Subjects were grouped based on surgical status (33 ACLR patients and 31 healthy controls). 3D motion capture synchronized with force plates was used to capture the landing phase of three successful trials of single hop for distance during a single data collection session. Peak values during the loading phase were analysed. Subjects additionally completed three successful trials of the triple hop for distance Tegner activity scale and International Knee Document Committee 2000 (IKDC). Controls demonstrated greater peak knee flexion and greater internal knee extension moment and hip extension moment than ACLR subjects. Within the ACLR group, the healthy limb exhibited greater peak knee flexion, hip flexion, hip extension moment, single hop and triple hops for distance and normalized quadriceps strength. Patients who undergo anterior cruciate ligament reconstruction land in a more extended posture when compared to healthy controls and compared to their healthy limb. III.

Bandwidth broadening of a graphene-based circular polarization converter by phase compensation.

PubMed

Gao, Xi; Yang, Wanli; Cao, Weiping; Chen, Ming; Jiang, Yannan; Yu, Xinhua; Li, Haiou

2017-10-02

We present a broadband tunable circular polarization converter composed of a single graphene sheet patterned with butterfly-shaped holes, a dielectric spacer, and a 7-layer graphene ground plane. It can convert a linearly polarized wave into a circularly polarized wave in reflection mode. The polarization converter can be dynamically tuned by varying the Fermi energy of the single graphene sheet. Furthermore, the 7-layer graphene acting as a ground plane can modulate the phase of its reflected wave by controlling the Femi energy, which provides constructive interference condition at the surface of the single graphene sheet in a broad bandwidth and therefore significantly broadens the tunable bandwidth of the proposed polarization converter.

Shot-noise-limited monitoring and phase locking of the motion of a single trapped ion.

PubMed

Bushev, P; Hétet, G; Slodička, L; Rotter, D; Wilson, M A; Schmidt-Kaler, F; Eschner, J; Blatt, R

2013-03-29

We perform a high-resolution real-time readout of the motion of a single trapped and laser-cooled Ba+ ion. By using an interferometric setup, we demonstrate a shot-noise-limited measurement of thermal oscillations with a resolution of 4 times the standard quantum limit. We apply the real-time monitoring for phase control of the ion motion through a feedback loop, suppressing the photon recoil-induced phase diffusion. Because of the spectral narrowing in the phase-locked mode, the coherent ion oscillation is measured with a resolution of about 0.3 times the standard quantum limit.

Designing scattering-free isotropic index profiles using phase-amplitude equations

NASA Astrophysics Data System (ADS)

King, C. G.; Horsley, S. A. R.; Philbin, T. G.

2018-05-01

The Helmholtz equation can be written as coupled equations for the amplitude and phase. By considering spatial phase distributions corresponding to reflectionless wave propagation in the plane and solving for the amplitude in terms of this phase, we designed two-dimensional graded-index media which do not scatter light. We give two illustrative examples, the first of which is a periodic grating for which diffraction is completely suppressed at a single frequency at normal incidence to the periodicity. The second example is a medium which behaves as a "beam shifter" at a single frequency; acting to laterally shift a plane wave, or sufficiently wide beam, without reflection.

Emerging single-phase state in small manganite nanodisks

DOE PAGES

Shao, Jian; Liu, Hao; Zhang, Kai; ...

2016-08-01

In complex oxides systems such as manganites, electronic phase separation (EPS), a consequence of strong electronic correlations, dictates the exotic electrical and magnetic properties of these materials. A fundamental yet unresolved issue is how EPS responds to spatial confinement; will EPS just scale with size of an object, or will the one of the phases be pinned? Understanding this behavior is critical for future oxides electronics and spintronics because scaling down of the system is unavoidable for these applications. In this work, we use La 0.325Pr 0.3Ca 0.375MnO 3 (LPCMO) single crystalline disks to study the effect of spatial confinementmore » on EPS. The EPS state featuring coexistence of ferromagnetic metallic and charge order insulating phases appears to be the low-temperature ground state in bulk, thin films, and large disks, a previously unidentified ground state (i.e., a single ferromagnetic phase state emerges in smaller disks). The critical size is between 500 nm and 800 nm, which is similar to the characteristic length scale of EPS in the LPCMO system. The ability to create a pure ferromagnetic phase in manganite nanodisks is highly desirable for spintronic applications.« less

Molecular ways to nanoscale particles and films

NASA Astrophysics Data System (ADS)

Shen, H.; Mathur, S.

2002-06-01

Chemical routes for the synthesis of nanoparticles and films are proving to be highly efficient and versatile in tailoring the elemental combination and intrinsic properties of the target materials. The use of molecular compounds allows a controlled interaction of atoms or molecules, when compared to the solid-state methods, resulting in the formation of compositionally homogeneous deposits or uniform solid particles. Assembling all the elements forming the material in a single molecular compound, the so-called single-source approach augments the formation of nanocrystalline phases at low temperatures with atomically precise structures. To this end, we have shown that predefined reaction (decomposition) chemistry of precursors enforces a molecular level homogeneity in the obtained materials. Following the single-step conversions of appropriate molecular sources, we have obtained films and nanoparticles of oxides (Fe3O4, BaTiO3, ZnAl2O4, CoAl2O4), metal/oxide composites (Ge/GeO2) and ceramic-ceramic composites (LnAIO3/AI2O3; Ln = Pr, Nd). For a comparative evaluation, CoAl2O4 nanoparticles were prepared by both single- and multi-component routes; whereas the single-source approach yielded monophasic high purity spinels, phase contamination, due to monometal phases, was observed in the ceramic obtained from multicomponent mixture. An account of the size-controlled synthesis and characterisation of the new ceramics and composites is presented.

Single-particle structure determination by correlations of snapshot X-ray diffraction patterns (CXIDB ID 20)

DOE Data Explorer

Starodub, D.

2013-03-25

This deposition includes the diffraction images generated by the paired polystyrene spheres in random orientations. These images were used to determine and phase the single particle diffraction volume from their autocorrelation functions.

Single-phase dual-energy CT allows for characterization of renal masses as benign or malignant.

PubMed

Graser, Anno; Becker, Christoph R; Staehler, Michael; Clevert, Dirk A; Macari, Michael; Arndt, Niko; Nikolaou, Konstantin; Sommer, Wieland; Stief, Christian; Reiser, Maximilian F; Johnson, Thorsten R C

2010-07-01

To evaluate the diagnostic accuracy of dual-energy CT (DECT) in renal mass characterization using a single-phase acquisition. A total of 202 patients (148 males, 54 females; 63 +/- 13 years) with ultrasound-based suspicion of a renal mass underwent unenhanced single energy and nephrographic phase DECT on a dual source scanner (Siemens Somatom Definition Dual Source, n = 174; Somatom Definition Flash, n = 28). Scan parameters for DECT were: tube potential, 80/100 and 100/Sn140 kVp; exposure, 404/300 and 96/232 effective mAs; collimation, 14 x 1.2/32 x 0.6 mm. Two abdominal radiologists assessed DECT and SECT image quality and noise on a 5-point visual analogue scale. Using solely the DE acquisition including virtual nonenhanced (VNE) and color coded iodine images that enable direct visualization of iodine, masses were characterized as benign or malignant. In a second reading session after 34 to 72 (average: 55) days, the same assessment was again performed using both the true nonenhanced (TNE) and nephrographic phase scans thereby simulating conventional single-energy CT. Sensitivities, specificities, diagnostic accuracies, and interpretation times and were recorded for both reading paradigms. Dose reduction of a single-phase over a dual-phase protocol was calculated. Results were tested for statistical significance using the paired Wilcoxon signed rank test and student t test. Differences in sensitivities were tested for significance using the McNemar test. Of the 202 patients, 115 (56.9%) underwent surgical resection of renal masses. Histopathology showed malignancy in 99 and benign tumors in 18 patients, in 48 patients (23.7%), follow-up imaging showed size stability of lesions diagnosed as benign, and 37 patients (18.3%) had no mass. Based on DECT only, 95/99 (96.0%) patients with malignancy and 96/103 (93.2%) patients without malignancy were correctly identified, for an overall accuracy of 94.6%. The dual-phase approach identified 96/99 (97.0%) and 98/103 (95.1%), accuracy 96.0%, P > 0.05 for both. Mean interpretation time was 2.2 +/- 0.8 minutes for DECT, and 3.5 +/- 1.0 minutes for the dual-phase protocol, P < 0.001. Mean VNE/TNE image quality was 1.68 +/- 0.65/1.30 +/- 0.59, noise was 2.03 +/- 0.57/1.18 +/- 0.29, P < 0.001 for both. Omission of the true unenhanced phase lead to a 48.9 +/- 7.0% dose reduction. DECT allows for fast and accurate characterization of renal masses in a single-phase acquisition. Interpretation of color coded images significantly reduces interpretation time. Omission of a nonenhanced acquisition can reduce radiation exposure by almost 50%.

Auditory-nerve single-neuron thresholds to electrical stimulation from scala tympani electrodes.

PubMed

Parkins, C W; Colombo, J

1987-12-31

Single auditory-nerve neuron thresholds were studied in sensory-deafened squirrel monkeys to determine the effects of electrical stimulus shape and frequency on single-neuron thresholds. Frequency was separated into its components, pulse width and pulse rate, which were analyzed separately. Square and sinusoidal pulse shapes were compared. There were no or questionably significant threshold differences in charge per phase between sinusoidal and square pulses of the same pulse width. There was a small (less than 0.5 dB) but significant threshold advantage for 200 microseconds/phase pulses delivered at low pulse rates (156 pps) compared to higher pulse rates (625 pps and 2500 pps). Pulse width was demonstrated to be the prime determinant of single-neuron threshold, resulting in strength-duration curves similar to other mammalian myelinated neurons, but with longer chronaxies. The most efficient electrical stimulus pulse width to use for cochlear implant stimulation was determined to be 100 microseconds/phase. This pulse width delivers the lowest charge/phase at threshold. The single-neuron strength-duration curves were compared to strength-duration curves of a computer model based on the specific anatomy of auditory-nerve neurons. The membrane capacitance and resulting chronaxie of the model can be varied by altering the length of the unmyelinated termination of the neuron, representing the unmyelinated portion of the neuron between the habenula perforata and the hair cell. This unmyelinated segment of the auditory-nerve neuron may be subject to aminoglycoside damage. Simulating a 10 micron unmyelinated termination for this model neuron produces a strength-duration curve that closely fits the single-neuron data obtained from aminoglycoside deafened animals. Both the model and the single-neuron strength-duration curves differ significantly from behavioral threshold data obtained from monkeys and humans with cochlear implants. This discrepancy can best be explained by the involvement of higher level neurologic processes in the behavioral responses. These findings suggest that the basic principles of neural membrane function must be considered in developing or analyzing electrical stimulation strategies for cochlear prostheses if the appropriate stimulation of frequency specific populations of auditory-nerve neurons is the objective.

Disappearance of the force-free current configuration at the first order vortex lattice phase transition in YBa 2Cu 3O 7-δ single crystals

NASA Astrophysics Data System (ADS)

van der Beek, C. J.; Indenbom, M. V.; Berseth, V.; Benoit, W.; Erb, A.; Flükiger, R.

1997-08-01

The anisotropy in the transverse AC susceptibility of YBa2Cu3O7-δ single crystals, induced by the periodic appearance of a force-free current configuration upon rotation of a superimposed DC field in the crystal plane, disappears at the vortex phase transition, indicating the loss of the vortex lines' stability against mutual cutting.

Permanent split capacitor single phase electric motor system

DOEpatents

Kirschbaum, Herbert S.

1984-01-01

A permanent split capacitor single phase electric motor achieves balanced operation at more than one operating point by adjusting the voltage supplied to the main and auxiliary windings and adjusting the capacitance in the auxiliary winding circuit. An intermediate voltage tap on an autotransformer supplies voltage to the main winding for low speed operation while a capacitive voltage divider is used to adjust the voltage supplied to the auxiliary winding for low speed operation.

TNT Metabolites in Animal Tissues

DTIC Science & Technology

1991-06-01

bonded to the silica surface contained both a C18 (reversed-phase function) and a secondary amine (anioni exchange function) incorporated into a single ...contains both a C18, (reversed-phase function) and a secondary amine, (anion exchange function) incorporated into a single ligand in a 1:1 ratio. The...and store at 4°C. 4. Dosing of Mice with [14CITNT Young adult mice (Swiss Webster outbred strain) of both sexes weighing approximately 30 grams each

Geometric relationships for homogenization in single-phase binary alloy systems

NASA Technical Reports Server (NTRS)

Unnam, J.; Tenney, D. R.; Stein, B. A.

1978-01-01

A semiempirical relationship is presented which describes the extent of interaction between constituents in single-phase binary alloy systems having planar, cylindrical, or spherical interfaces. This relationship makes possible a quick estimate of the extent of interaction without lengthy numerical calculations. It includes two parameters which are functions of mean concentration and interface geometry. Experimental data for the copper-nickel system are included to demonstrate the usefulness of this relationship.

Electrically Driven Single Phase Thermal Management: STP-H5 EHD Experiment

NASA Technical Reports Server (NTRS)

Didion, Jeffrey R.

2016-01-01

The Electrically Driven Single Phase Thermal Management: STP-H5 iEHDS Experiment is a technology demonstration of prototype proof of concept hardware to establish the feasilibilty and long term operation of this hardware. This is a structural thermal plate that will operate continuous as part of the STP-H5 ISEM experiment for up to 18 months. This presentation discusses the design, fabrication and environmental operational paramertes of the experiment hardware.

Use of TCSR with Split Windings for Shortening the Spar Cycle Time in 500 kV Lines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matinyan, A. M., E-mail: al-drm@mail.ru; Peshkov, M. V.; Karpov, V. N.

The arc-fault recharge phenomenon in single-phase automatic reclosure (SPAR) of a line is examined. Abrief description is given of the design of a 500 kV thyristor controlled shunt reactor (TCSR) with split valve-side windings. This type of TCSR is shown to effectively quench a single-phase arc fault in a power transmission line and shortens the SPAR cycle time.

Phase-shifting point diffraction interferometer mask designs

DOEpatents

Goldberg, Kenneth Alan

2001-01-01

In a phase-shifting point diffraction interferometer, different image-plane mask designs can improve the operation of the interferometer. By keeping the test beam window of the mask small compared to the separation distance between the beams, the problem of energy from the reference beam leaking through the test beam window is reduced. By rotating the grating and mask 45.degree., only a single one-dimensional translation stage is required for phase-shifting. By keeping two reference pinholes in the same orientation about the test beam window, only a single grating orientation, and thus a single one-dimensional translation stage, is required. The use of a two-dimensional grating allows for a multiplicity of pinholes to be used about the pattern of diffracted orders of the grating at the mask. Orientation marks on the mask can be used to orient the device and indicate the position of the reference pinholes.

High Zn Content Single-phase RS-MgZnO Suitable for Solar-blind Frequency Applications

NASA Astrophysics Data System (ADS)

Liang, H. L.; Mei, Z. X.; Liu, Z. L.; Guo, Y.; Azarov, A. Yu.; Kuznetsov, A. Yu.; Hallen, A.; Du, X. L.

2010-11-01

Single-phase rock-salt MgZnO films with high Zn content were successfully fabricated on the templates of MgO (111)/α-sapphire (0001) by radio-frequency plasma assisted molecular beam epitaxy. The influence of growth temperature on epitaxy of MgZnO alloy films was investigated by the combined studies of crystal structures, compositions, and optical properties. It is found that the incorporation of Zn atoms into the rock-salt MgZnO films is greatly enhanced at low temperature, confirmed by in-situ reflection high-energy electron diffraction observations and ex-situ X-ray diffraction characterization. Zn fraction in the single-phase rock-salt Mg0.53Zn0.47O film was determined by Rutherford backscattering spectrometry. Optical properties of the films were investigated by transmittance spectroscopy and reflectance spectroscopy, both of which demonstrate the solar-blind band gap and its dependence on Zn content.

Expandable and reconfigurable instrument node arrays

NASA Technical Reports Server (NTRS)

Hilliard, Lawrence M. (Inventor); Deshpande, Manohar (Inventor)

2012-01-01

An expandable and reconfigurable instrument node includes a feature detection means and a data processing portion in communication with the feature detection means, the data processing portion configured and disposed to process feature information. The instrument node further includes a phase locked loop (PLL) oscillator in communication with the data processing portion, the PLL oscillator configured and disposed to provide PLL information to the processing portion. The instrument node further includes a single tone transceiver and a pulse transceiver in communication with the PLL oscillator, the single tone transceiver configured and disposed to transmit or receive a single tone for phase correction of the PLL oscillator and the pulse transceiver configured and disposed to transmit and receive signals for phase correction of the PLL oscillator. The instrument node further includes a global positioning (GPA) receiver in communication with the processing portion, the GPS receiver configured and disposed to establish a global position of the instrument node.

Friction and Wear Modifiers Using Solvent Partitioning of Hydrophilic Surface-interactive Chemicals Contained in Boundary Layer-targeted Emulsions

NASA Technical Reports Server (NTRS)

Richmond, Robert Chafee (Inventor); Schramm, Jr., Harry F. (Inventor); Defalco, Francis G. (Inventor)

2013-01-01

A wear and/or friction reducing additive for a lubricating fluid in which the additive is a combination of a moderately hydrophilic single-phase compound and an anti-wear and/or anti-friction aqueous salt solution. The aqueous salt solution produces a coating on boundary layer surfaces. The lubricating fluid can be an emulsion-free hydrophobic oil, hydraulic fluid, antifreeze, or water. Preferably, the moderately hydrophilic single-phase compound is sulfonated castor oil and the aqueous salt solution additionally contains boric acid and zinc oxide. The emulsions produced by the aqueous salt solutions, the moderately hydrophilic single-phase compounds, or the combination thereof provide targeted boundary layer organizers that significantly enhance the anti-wear and/or anti-friction properties of the base lubricant by decreasing wear and/or friction of sliding and/or rolling surfaces at boundary layers.

Single-phase and well-dispersed Cu1.75S nanocrystals by ambient pressure diethylene glycol solution synthesis

NASA Astrophysics Data System (ADS)

Zheng, Xuerong; Jin, Zhengguo; Liu, Hui; Wang, Yueqiu; Wang, Xin; Du, Haiyan

2013-02-01

Single-phase, well-dispersed Cu1.75S nanocrystals were synthesized by an ambient pressure, hydrazine hydrate and ethylenediamine co-assisted diethylene glycol based solution chemical process using copper chloride and thioacetamide as precursors at the temperature range from 180 to 210 °C. Influence of hydrazine hydrate and ethylenediamine adding amounts, synthetic temperature on crystal growth, size distribution and optical properties of the synthesized Cu1.75S nanocrystals were investigated by XRD, TEM, HRTEM, EDX and UV-vis measurements. The synthetic reaction at above 200 °C grew flaky-shaped nanocrystals with relatively narrow size distribution. The formation of single-phase Cu1.75S nanocrystals in the diethylene glycol based solution process might be involved in the presence of intermediate [Cu(en)n]1+ and [Cu(NH3)4]2+ complexes in reaction solution, providing a stable Cu(I) and Cu(II) valent-mixed precursor.

Liquid Acquisition Device Testing with Sub-Cooled Liquid Oxygen

NASA Technical Reports Server (NTRS)

Jurns, John M.; McQuillen, John B.

2008-01-01

When transferring propellant in space, it is most efficient to transfer single phase liquid from a propellant tank to an engine. In earth s gravity field or under acceleration, propellant transfer is fairly simple. However, in low gravity, withdrawing single-phase fluid becomes a challenge. A variety of propellant management devices (PMD) are used to ensure single-phase flow. One type of PMD, a liquid acquisition device (LAD) takes advantage of capillary flow and surface tension to acquire liquid. Previous experimental test programs conducted at NASA have collected LAD data for a number of cryogenic fluids, including: liquid nitrogen (LN2), liquid oxygen (LOX), liquid hydrogen (LH2), and liquid methane (LCH4). The present work reports on additional testing with sub-cooled LOX as part of NASA s continuing cryogenic LAD development program. Test results extend the range of LOX fluid conditions examined, and provide insight into factors affecting predicting LAD bubble point pressures.

Fourier phase retrieval with a single mask by Douglas-Rachford algorithms.

PubMed

Chen, Pengwen; Fannjiang, Albert

2018-05-01

The Fourier-domain Douglas-Rachford (FDR) algorithm is analyzed for phase retrieval with a single random mask. Since the uniqueness of phase retrieval solution requires more than a single oversampled coded diffraction pattern, the extra information is imposed in either of the following forms: 1) the sector condition on the object; 2) another oversampled diffraction pattern, coded or uncoded. For both settings, the uniqueness of projected fixed point is proved and for setting 2) the local, geometric convergence is derived with a rate given by a spectral gap condition. Numerical experiments demonstrate global, power-law convergence of FDR from arbitrary initialization for both settings as well as for 3 or more coded diffraction patterns without oversampling. In practice, the geometric convergence can be recovered from the power-law regime by a simple projection trick, resulting in highly accurate reconstruction from generic initialization.

Performance of Four-Leg VSC based DSTATCOM using Single Phase P-Q Theory

NASA Astrophysics Data System (ADS)

Jampana, Bangarraju; Veramalla, Rajagopal; Askani, Jayalaxmi

2017-02-01

This paper presents single-phase P-Q theory for four-leg VSC based distributed static compensator (DSTATCOM) in the distribution system. The proposed DSTATCOM maintains unity power factor at source, zero voltage regulation, eliminates current harmonics, load balancing and neutral current compensation. The advantage of using four-leg VSC based DSTATCOM is to eliminate isolated/non-isolated transformer connection at point of common coupling (PCC) for neutral current compensation. The elimination of transformer connection at PCC with proposed topology will reduce cost of DSTATCOM. The single-phase P-Q theory control algorithm is used to extract fundamental component of active and reactive currents for generation of reference source currents which is based on indirect current control method. The proposed DSTATCOM is modelled and the results are validated with various consumer loads under unity power factor and zero voltage regulation modes in the MATLAB R2013a environment using simpower system toolbox.

Gradient polymer-disposed liquid crystal single layer of large nematic droplets for modulation of laser light.

PubMed

Hadjichristov, Georgi B; Marinov, Yordan G; Petrov, Alexander G

2011-06-01

The light modulating ability of gradient polymer-disposed liquid crystal (PDLC) single layer of large droplets formed by nematic E7 in UV-cured polymer NOA65 is studied. Operating at relatively low voltages, such PDLC film with a of thickness 10-25 μm and droplet size up to 50 μm exhibits a good contrast ratio and is capable of producing a large phase shift for the propagating coherent light. For a linearly polarized He-Ne laser (λ=633 nm), an electrically commanded phase shift as large as π/2 can be obtained by the large-droplet region of the film. The electrically produced phase shift and its spatial profile controlled by the thickness of the gradient PDLC single layers of large nematic droplets can be useful for tunable spatial light modulators and other devices for active control of laser light.

Friction and Wear Modifiers Using Solvent Partitioning of Hydrophilic Surface-Interactive Chemicals Contained in Boundary Layer-Targeted Emulsions

NASA Technical Reports Server (NTRS)

Defalco, Francis G. (Inventor); Richmond, Robert Chaffee (Inventor); Schramm, Jr., Harry F. (Inventor)

2017-01-01

A wear and/or friction reducing additive for a lubricating fluid in which the additive is a combination of a moderately hydrophilic single-phase compound and an anti-wear and/or anti-friction aqueous salt solution. The aqueous salt solution produces a coating on boundary layer surfaces. The lubricating fluid can be an emulsion-free hydrophobic oil, hydraulic fluid, antifreeze, water, or a water-based lubricant. Preferably, the moderately hydrophilic single-phase compound is sulfonated castor oil and the aqueous salt solution additionally contains boric acid and zinc oxide. The emulsions produced by the aqueous salt solutions, the moderately hydrophilic single-phase compounds, or the combination thereof provide targeted boundary layer organizers that significantly enhance the anti-wear and/or anti-friction properties of the base lubricant by decreasing wear and/or friction of sliding and/or rolling surfaces at boundary layers.

Friction and Wear Modifiers Using Solvent Partitioning of Hydrophilic Surface-Interactive Chemicals Contained in Boundary Layer-Targeted Emulsions

NASA Technical Reports Server (NTRS)

Defalco, Francis G. (Inventor); Richmond, Robert Chaffee (Inventor); Schramm, Harry F., Jr. (Inventor)

2016-01-01

A wear and/or friction reducing additive for a lubricating fluid in which the additive is a combination of a moderately hydrophilic single-phase compound and an anti-wear and/or anti-friction aqueous salt solution. The aqueous salt solution produces a coating on boundary layer surfaces. The lubricating fluid can be an emulsion-free hydrophobic oil, hydraulic fluid, antifreeze, or water. Preferably, the moderately hydrophilic single-phase compound is sulfonated castor oil and the aqueous salt solution additionally contains boric acid and zinc oxide. The emulsions produced by the aqueous salt solutions, the moderately hydrophilic single-phase compounds, or the combination thereof provide targeted boundary layer organizers that significantly enhance the anti-wear and/or anti-friction properties of the base lubricant by decreasing wear and/or friction of sliding and/or rolling surfaces at boundary layers.

A High Power Density Single-Phase PWM Rectifier With Active Ripple Energy Storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Ruxi; Wang, Fei; Boroyevich, Dushan

It is well known that single-phase pulse width modulation rectifiers have second-order harmonic currents and corresponding ripple voltages on the dc bus. The low-frequency harmonic current is normally filtered using a bulk capacitor in the bus, which results in low power density. However, pursuing high power density in converter design is a very important goal in the aerospace applications. This paper studies methods for reducing the energy storage capacitor for single-phase rectifiers. The minimum ripple energy storage requirement is derived independently of a specific topology. Based on theminimum ripple energy requirement, the feasibility of the active capacitor s reduction schemesmore » is verified. Then, we propose a bidirectional buck boost converter as the ripple energy storage circuit, which can effectively reduce the energy storage capacitance. The analysis and design are validated by simulation and experimental results.« less

Determination of the stacking fault density in highly defective single GaAs nanowires by means of coherent diffraction imaging

NASA Astrophysics Data System (ADS)

Davtyan, Arman; Biermanns, Andreas; Loffeld, Otmar; Pietsch, Ullrich

2016-06-01

Coherent x-ray diffraction imaging is used to measure diffraction patterns from individual highly defective nanowires, showing a complex speckle pattern instead of well-defined Bragg peaks. The approach is tested for nanowires of 500 nm diameter and 500 nm height predominately composed by zinc-blende (ZB) and twinned zinc-blende (TZB) phase domains. Phase retrieval is used to reconstruct the measured 2-dimensional intensity patterns recorded from single nanowires with 3.48 nm and 0.98 nm spatial resolution. Whereas the speckle amplitudes and distribution are perfectly reconstructed, no unique solution could be obtained for the phase structure. The number of phase switches is found to be proportional to the number of measured speckles and follows a narrow number distribution. Using data with 0.98 nm spatial resolution the mean number of phase switches is in reasonable agreement with estimates taken from TEM. However, since the resolved phase domain still is 3-4 times larger than a single GaAs bilayer we explain the non-ambiguous phase reconstruction by the fact that depending on starting phase and sequence of subroutines used during the phase retrieval the retrieved phase domain host a different sequence of randomly stacked bilayers. Modelling possible arrangements of bilayer sequences within a phase domain demonstrate that the complex speckle patterns measured can indeed be explained by the random arrangement of the ZB and TZB phase domains.

Self-referenced locking of optical coherence by single-detector electronic-frequency tagging

NASA Astrophysics Data System (ADS)

Shay, T. M.; Benham, Vincent; Spring, Justin; Ward, Benjamin; Ghebremichael, F.; Culpepper, Mark A.; Sanchez, Anthony D.; Baker, J. T.; Pilkington, D.; Berdine, Richard

2006-02-01

We report a novel coherent beam combining technique. This is the first actively phase locked optical fiber array that eliminates the need for a separate reference beam. In addition, only a single photodetector is required. The far-field central spot of the array is imaged onto the photodetector to produce the phase control loop signals. Each leg of the fiber array is phase modulated with a separate RF frequency, thus tagging the optical phase shift for each leg by a separate RF frequency. The optical phase errors for the individual array legs are separated in the electronic domain. In contrast with the previous active phase locking techniques, in our system the reference beam is spatially overlapped with all the RF modulated fiber leg beams onto a single detector. The phase shift between the optical wave in the reference leg and in the RF modulated legs is measured separately in the electronic domain and the phase error signal is feedback to the LiNbO 3 phase modulator for that leg to minimize the phase error for that leg relative to the reference leg. The advantages of this technique are 1) the elimination of the reference beam and beam combination optics and 2) the electronic separation of the phase error signals without any degradation of the phase locking accuracy. We will present the first theoretical model for self-referenced LOCSET and describe experimental results for a 3 x 3 array.

Preliminary Two-Phase Terry Turbine Nozzle Models for RCIC Off-Design Operation Conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Haihua; O'Brien, James

This report presents the effort to extend the single-phase analytical Terry turbine model to cover two-phase off-design conditions. The work includes: (1) adding well-established two-phase choking models – the Isentropic Homogenous Equilibrium Model (IHEM) and Moody’s model, and (2) theoretical development and implementation of a two-phase nozzle expansion model. The two choking models provide bounding cases for the two-phase choking mass flow rate. The new two-phase Terry turbine model uses the choking models to calculate the mass flow rate, the critical pressure at the nozzle throat, and steam quality. In the divergent stage, we only consider the vapor phase withmore » a similar model for the single-phase case by assuming that the liquid phase would slip along the wall with a much slower speed and will not contribute the impulse on the rotor. We also modify the stagnation conditions according to two-phase choking conditions at the throat and the cross-section areas for steam flow at the nozzle throat and at the nozzle exit. The new two-phase Terry turbine model was benchmarked with the same steam nozzle test as for the single-phase model. Better agreement with the experimental data is observed than from the single-phase model. We also repeated the Terry turbine nozzle benchmark work against the Sandia CFD simulation results with the two-phase model for the pure steam inlet nozzle case. The RCIC start-up tests were simulated and compared with the single-phase model. Similar results are obtained. Finally, we designed a new RCIC system test case to simulate the self-regulated Terry turbine behavior observed in Fukushima accidents. In this test, a period inlet condition for the steam quality varying from 1 to 0 is applied. For the high quality inlet period, the RCIC system behaves just like the normal operation condition with a high pump injection flow rate and a nominal steam release rate through the turbine, with the net addition of water to the primary system; for the low quality inlet period, the RCIC turbine shaft work dramatically decreases and results in a much reduced pump injection flow rate, and the mixture flow rate through the turbine increases due to the high liquid phase flow rate. The net effect for this period is net removal of coolant from the primary loop. With the periodic addition and removal of coolant to the primary loop, the self-regulation mode of the RCIC system can be maintained for a quite long time. Both the IHEM and Moody’s models generate similar phenomena; however noticeable differences can be observed.« less

Single-dose palonosetron for prevention of chemotherapy-induced nausea and vomiting in patients with aggressive non-Hodgkin's lymphoma receiving moderately emetogenic chemotherapy containing steroids: results of a phase II study from the Gruppo Italiano per lo Studio dei Linfomi (GISL).

PubMed

Di Renzo, Nicola; Montanini, Antonella; Mannina, Donato; Dondi, Alessandra; Muci, Stefania; Mancuso, Salvatrice; De Paolis, M Rosaria; Plati, Caterina; Stelitano, Caterina; Patti, Catia; Olivieri, Attilio; Liardo, Eliana; Buda, Gabriele; Cantaffa, Renato; Federico, Massimo

2011-10-01

The control of nausea and vomiting induced by chemotherapy is paramount for overall treatment success in cancer patients. Antiemetic therapy during chemotherapy in lymphoma patients generally consists of anti-serotoninergic drugs and dexamethasone. The aim of this trial was to evaluate the efficacy of a single dose of palonosetron, a second-generation serotonin type 3 (5-HT(3)) receptor antagonist, in patients with aggressive non-Hodgkin's lymphoma receiving moderately emetogenic chemotherapy (MEC) containing steroids. Patients received a single intravenous bolus of palonosetron (0.25 mg) before administration of chemotherapy. Complete response (CR) defined as no vomiting and no rescue therapy during overall phase (0-120 h) was the primary endpoint. Complete control (CC) defined as CR and only mild nausea was a secondary endpoint. Eighty-six evaluable patients entered in the study. A CR was observed in 74 patients (86.0%) during the overall phase; the CR during the acute (0-24 h) and delayed (24-120 h) phases was 90.7% and 88.4%, respectively. CC was 89.5% during the acute and 84.9% during the delayed phase; the overall CC was 82.6%. This was the first trial, which demonstrated the efficacy of a single dose of palonosetron in control CINV in patients with aggressive non-Hodgkin's lymphoma receiving MEC regimen containing steroids.

Effect of Magnesium Content and Processing Conditions on Phase Formation and Stability in Mg2+ δ Si0.3Sn0.7

NASA Astrophysics Data System (ADS)

Goyal, Gagan K.; Dasgupta, T.

2018-03-01

Mg2+ δ Si0.3Sn0.7 compositions with nominal Mg content of δ = 0, 0.2 are synthesized using a single-step quartz tube reaction method with different heating rates and holding times. The resulting powders are sintered using a uniaxial induction hot press under similar conditions to produce near-dense compacts. The effect of Mg content and processing conditions on the phase formation and its stability are studied using x-ray diffraction measurements, scanning electron microscopy (SEM) with elemental mapping and compositional analysis using energy dispersive spectroscopy (EDS). Results indicate that with sufficient Mg content and shorter synthesis time, the powder remains single phasic; however, prolonged heat treatment during synthesis results in Mg loss and causes the system to become biphasic. Compaction results in single-phase formation in all the specimens. This is attributed to the removal of the low-melting secondary Sn-rich phases present in the system. The decomposition of the specimens depends on the Mg content after the compaction step with a δ around - 0.15 necessary to preserve the single phase. The decomposition also results in Mg enrichment of the matrix (due to formation of elemental Sn), thereby acting as a self-healing mechanism. Annealing the dense products at 773 K for 24 h in static vacuum is carried out. Progressive Mg loss is observed resulting in degradation of the specimen.

Evolution dynamics of a model for gene duplication under adaptive conflict

NASA Astrophysics Data System (ADS)

Ancliff, Mark; Park, Jeong-Man

2014-06-01

We present and solve the dynamics of a model for gene duplication showing escape from adaptive conflict. We use a Crow-Kimura quasispecies model of evolution where the fitness landscape is a function of Hamming distances from two reference sequences, which are assumed to optimize two different gene functions, to describe the dynamics of a mixed population of individuals with single and double copies of a pleiotropic gene. The evolution equations are solved through a spin coherent state path integral, and we find two phases: one is an escape from an adaptive conflict phase, where each copy of a duplicated gene evolves toward subfunctionalization, and the other is a duplication loss of function phase, where one copy maintains its pleiotropic form and the other copy undergoes neutral mutation. The phase is determined by a competition between the fitness benefits of subfunctionalization and the greater mutational load associated with maintaining two gene copies. In the escape phase, we find a dynamics of an initial population of single gene sequences only which escape adaptive conflict through gene duplication and find that there are two time regimes: until a time t* single gene sequences dominate, and after t* double gene sequences outgrow single gene sequences. The time t* is identified as the time necessary for subfunctionalization to evolve and spread throughout the double gene sequences, and we show that there is an optimum mutation rate which minimizes this time scale.

Phase diagram and electronic indication of high-temperature superconductivity at 65 K in single-layer FeSe films.

PubMed

He, Shaolong; He, Junfeng; Zhang, Wenhao; Zhao, Lin; Liu, Defa; Liu, Xu; Mou, Daixiang; Ou, Yun-Bo; Wang, Qing-Yan; Li, Zhi; Wang, Lili; Peng, Yingying; Liu, Yan; Chen, Chaoyu; Yu, Li; Liu, Guodong; Dong, Xiaoli; Zhang, Jun; Chen, Chuangtian; Xu, Zuyan; Chen, Xi; Ma, Xucun; Xue, Qikun; Zhou, X J

2013-07-01

The recent discovery of possible high-temperature superconductivity in single-layer FeSe films has generated significant experimental and theoretical interest. In both the cuprate and the iron-based high-temperature superconductors, superconductivity is induced by doping charge carriers into the parent compound to suppress the antiferromagnetic state. It is therefore important to establish whether the superconductivity observed in the single-layer sheets of FeSe--the essential building blocks of the Fe-based superconductors--is realized by undergoing a similar transition. Here we report the phase diagram for an FeSe monolayer grown on a SrTiO3 substrate, by tuning the charge carrier concentration over a wide range through an extensive annealing procedure. We identify two distinct phases that compete during the annealing process: the electronic structure of the phase at low doping (N phase) bears a clear resemblance to the antiferromagnetic parent compound of the Fe-based superconductors, whereas the superconducting phase (S phase) emerges with the increase in doping and the suppression of the N phase. By optimizing the carrier concentration, we observe strong indications of superconductivity with a transition temperature of 65±5 K. The wide tunability of the system across different phases makes the FeSe monolayer ideal for investigating not only the physics of superconductivity, but also for studying novel quantum phenomena more generally.

Yuwipi

ERIC Educational Resources Information Center

Kemnitzer, Luis S.

1978-01-01

Analyzing the Yuwipi ceremony of the Dakota Sioux, this article describes a single performance and then discusses the Yuwipi in terms of its general meaning (light phase, dark phase, marginal phase, and feast). (JC)

Shock and Microstructural Characterization of the α-ω Phase Transition in Titanium Crystals

NASA Astrophysics Data System (ADS)

Morrow, Benjamin M.; Rigg, Paulo A.; Jones, David R.; Addessio, Francis L.; Trujillo, Carl P.; Saavedra, Ramon A.; Martinez, Daniel T.; Cerreta, Ellen K.

2017-12-01

A multicrystal comprised of a small number of large crystals of high-purity titanium and a [0001] oriented high-purity single crystal titanium sample were shock loaded using gas gun plate impact experiments. Tests were performed at stresses above the α {-}ω phase transition stress (for high-purity polycrystalline specimens) to observe the behavior of oriented crystals under similar conditions. Post-mortem characterization of the shocked microstructure was conducted on the single crystal sample to measure textures, and quantify phases and twinning. The apparent activation of plastic and transformation mechanisms was dependent upon crystal orientation. Specifically, the [0001] crystal showed a higher Hugoniot elastic limit than the [10\\bar{1}0] or [3\\bar{1}\\bar{4}4] orientations. The slope of velocity as a function of time was lower in the [0001] orientation than the other orientations during plastic deformation, indicating sluggish transformation kinetics for the α to ω phase transition for the [0001] oriented crystal. Microtexture measurements of a recovered [0001] oriented single crystal revealed the presence of retained ω phase after unloading, with orientations of the constituent phase fractions indicative of the forward α → ω transition, rather than the reverse ω → α transition, suggesting that the material never achieved a state of 100% ω phase.

Assembly and diploid architecture of an individual human genome via single-molecule technologies

PubMed Central

Pendleton, Matthew; Sebra, Robert; Pang, Andy Wing Chun; Ummat, Ajay; Franzen, Oscar; Rausch, Tobias; Stütz, Adrian M; Stedman, William; Anantharaman, Thomas; Hastie, Alex; Dai, Heng; Fritz, Markus Hsi-Yang; Cao, Han; Cohain, Ariella; Deikus, Gintaras; Durrett, Russell E; Blanchard, Scott C; Altman, Roger; Chin, Chen-Shan; Guo, Yan; Paxinos, Ellen E; Korbel, Jan O; Darnell, Robert B; McCombie, W Richard; Kwok, Pui-Yan; Mason, Christopher E; Schadt, Eric E; Bashir, Ali

2015-01-01

We present the first comprehensive analysis of a diploid human genome that combines single-molecule sequencing with single-molecule genome maps. Our hybrid assembly markedly improves upon the contiguity observed from traditional shotgun sequencing approaches, with scaffold N50 values approaching 30 Mb, and we identified complex structural variants (SVs) missed by other high-throughput approaches. Furthermore, by combining Illumina short-read data with long reads, we phased both single-nucleotide variants and SVs, generating haplotypes with over 99% consistency with previous trio-based studies. Our work shows that it is now possible to integrate single-molecule and high-throughput sequence data to generate de novo assembled genomes that approach reference quality. PMID:26121404

Ordered array of CoPc-vacancies filled with single-molecule rotors

NASA Astrophysics Data System (ADS)

Xie, Zheng-Bo; Wang, Ya-Li; Tao, Min-Long; Sun, Kai; Tu, Yu-Bing; Yuan, Hong-Kuan; Wang, Jun-Zhong

2018-05-01

We report the highly ordered array of CoPc-vacancies and the single-molecule rotors inside the vacancies. When CoPc molecules are deposited on Cd(0001) at low-temperature, three types of molecular vacancies appeared randomly in the CoPc monolayer. Annealing the sample to higher temperature leads to the spontaneous phase separation and self-organized arrangement of the vacancies. Highly ordered arrays of two-molecule vacancies and single-molecule vacancies have been obtained. In particular, there is a rotating CoPc molecule inside each single-molecule vacancy, which constitutes the array of single-molecule rotors. These results provide a new routine to fabricate the nano-machines on a large scale.

Assembly and diploid architecture of an individual human genome via single-molecule technologies.

PubMed

Pendleton, Matthew; Sebra, Robert; Pang, Andy Wing Chun; Ummat, Ajay; Franzen, Oscar; Rausch, Tobias; Stütz, Adrian M; Stedman, William; Anantharaman, Thomas; Hastie, Alex; Dai, Heng; Fritz, Markus Hsi-Yang; Cao, Han; Cohain, Ariella; Deikus, Gintaras; Durrett, Russell E; Blanchard, Scott C; Altman, Roger; Chin, Chen-Shan; Guo, Yan; Paxinos, Ellen E; Korbel, Jan O; Darnell, Robert B; McCombie, W Richard; Kwok, Pui-Yan; Mason, Christopher E; Schadt, Eric E; Bashir, Ali

2015-08-01

We present the first comprehensive analysis of a diploid human genome that combines single-molecule sequencing with single-molecule genome maps. Our hybrid assembly markedly improves upon the contiguity observed from traditional shotgun sequencing approaches, with scaffold N50 values approaching 30 Mb, and we identified complex structural variants (SVs) missed by other high-throughput approaches. Furthermore, by combining Illumina short-read data with long reads, we phased both single-nucleotide variants and SVs, generating haplotypes with over 99% consistency with previous trio-based studies. Our work shows that it is now possible to integrate single-molecule and high-throughput sequence data to generate de novo assembled genomes that approach reference quality.

Room-temperature ultrafast nonlinear spectroscopy of a single molecule

NASA Astrophysics Data System (ADS)

Liebel, Matz; Toninelli, Costanza; van Hulst, Niek F.

2018-01-01

Single-molecule spectroscopy aims to unveil often hidden but potentially very important contributions of single entities to a system's ensemble response. Albeit contributing tremendously to our ever growing understanding of molecular processes, the fundamental question of temporal evolution, or change, has thus far been inaccessible, thus painting a static picture of a dynamic world. Here, we finally resolve this dilemma by performing ultrafast time-resolved transient spectroscopy on a single molecule. By tracing the femtosecond evolution of excited electronic state spectra of single molecules over hundreds of nanometres of bandwidth at room temperature, we reveal their nonlinear ultrafast response in an effective three-pulse scheme with fluorescence detection. A first excitation pulse is followed by a phase-locked de-excitation pulse pair, providing spectral encoding with 25 fs temporal resolution. This experimental realization of true single-molecule transient spectroscopy demonstrates that two-dimensional electronic spectroscopy of single molecules is experimentally within reach.

Effects of the single-ion anisotropy on magnetic and thermodynamic properties of a ferrimagnetic mixed-spin (1, 3/2) cylindrical Ising nanowire

NASA Astrophysics Data System (ADS)

Wang, Wei; Bi, Jiang-lin; Liu, Rui-jia; Chen, Xu; Liu, Jin-ping

2016-10-01

Monte Carlo simulation has been performed in detail to study magnetic and thermodynamic properties of a ferrimagnetic mixed-spin (1, 3/2) cylindrical Ising nanowire with core-shell structure. The ground phase diagrams are obtained for different single-ion anisotropies. The system can display rich phase transitions such as the second- and first-order phase transitions, the tricritical points and the compensation points. Especially, emphasis has been given to the effects of the single-ion anisotropy and the temperate on the magnetization, the internal energy, the specific heat, the compensation points and hysteresis loops of the system as well as two sublattices. A number of characteristic phenomena such as such as various types of magnetization curves and triple, duadruple as well as quintuple hysteresis loops behaviors have been observed for certain physical parameters, originating from the competitions among the anisotropies, temperature and the longitudinal magnetic field. It is found that the single-ion anisotropy and the temperature strongly affect the coercivity and the remanence of the system. A satisfactory agreement can be achieved from comparisons between our results and previous theoretical and experimental works.

Single-Ion Solvation Free Energies and the Normal Hydrogen Electrode Potential in Methanol, Acetonitrile, and Dimethyl Sulfoxide

PubMed Central

Kelly, Casey P.; Cramer, Christopher J.; Truhlar, Donald G.

2008-01-01

The division of thermodynamic solvation free energies of electrolytes into ionic constituents is conventionally accomplished by using the single-ion solvation free energy of one reference ion, conventionally the proton, to set the single-ion scales. Thus the determination of the free energy of solvation of the proton in various solvents is a fundamental issue of central importance in solution chemistry. In the present article, relative solvation free energies of ions and ion-solvent clusters in methanol, acetonitrile, and dimethyl sulfoxide (DMSO) have been determined using a combination of experimental and theoretical gas-phase free energies of formation, solution-phase reduction potentials and acid dissociation constants, and gas-phase clustering free energies. Applying the cluster pair approximation to differences between these relative solvation free energies leads to values of −263.5, −260.2, and −273.3 kcal/mol for the absolute solvation free energy of the proton in methanol, acetonitrile, and DMSO, respectively. The final absolute proton solvation free energies are used to assign absolute values for the normal hydrogen electrode potential and the solvation free energies of other single ions in the above solvents. PMID:17214493

Tailoring the optical characteristics of microsized InP nanoneedles directly grown on silicon.

PubMed

Li, Kun; Sun, Hao; Ren, Fan; Ng, Kar Wei; Tran, Thai-Truong D; Chen, Roger; Chang-Hasnain, Connie J

2014-01-08

Nanoscale self-assembly offers a pathway to realize heterogeneous integration of III-V materials on silicon. However, for III-V nanowires directly grown on silicon, dislocation-free single-crystal quality could only be attained below certain critical dimensions. We recently reported a new approach that overcomes this size constraint, demonstrating the growth of single-crystal InGaAs/GaAs and InP nanoneedles with the base diameters exceeding 1 μm. Here, we report distinct optical characteristics of InP nanoneedles which are varied from mostly zincblende, zincblende/wurtzite-mixed, to pure wurtzite crystalline phase. We achieved, for the first time, pure single-crystal wurtzite-phase InP nanoneedles grown on silicon with bandgaps of 80 meV larger than that of zincblende-phase InP. Being able to attain excellent material quality while scaling up in size promises outstanding device performance of these nanoneedles. At room temperature, a high internal quantum efficiency of 25% and optically pumped lasing are demonstrated for single nanoneedle as-grown on silicon substrate. Recombination dynamics proves the excellent surface quality of the InP nanoneedles, which paves the way toward achieving multijunction photovoltaic cells, long-wavelength heterostructure lasers, and advanced photonic integrated circuits.

Analyser-based mammography using single-image reconstruction.

PubMed

Briedis, Dahliyani; Siu, Karen K W; Paganin, David M; Pavlov, Konstantin M; Lewis, Rob A

2005-08-07

We implement an algorithm that is able to decode a single analyser-based x-ray phase-contrast image of a sample, converting it into an equivalent conventional absorption-contrast radiograph. The algorithm assumes the projection approximation for x-ray propagation in a single-material object embedded in a substrate of approximately uniform thickness. Unlike the phase-contrast images, which have both directional bias and a bias towards edges present in the sample, the reconstructed images are directly interpretable in terms of the projected absorption coefficient of the sample. The technique was applied to a Leeds TOR[MAM] phantom, which is designed to test mammogram quality by the inclusion of simulated microcalcifications, filaments and circular discs. This phantom was imaged at varying doses using three modalities: analyser-based synchrotron phase-contrast images converted to equivalent absorption radiographs using our algorithm, slot-scanned synchrotron imaging and imaging using a conventional mammography unit. Features in the resulting images were then assigned a quality score by volunteers. The single-image reconstruction method achieved higher scores at equivalent and lower doses than the conventional mammography images, but no improvement of visualization of the simulated microcalcifications, and some degradation in image quality at reduced doses for filament features.

Phase-factor-dependent symmetries and quantum phases in a three-level cavity QED system.

PubMed

Fan, Jingtao; Yu, Lixian; Chen, Gang; Jia, Suotang

2016-05-03

Unlike conventional two-level particles, three-level particles may support some unitary-invariant phase factors when they interact coherently with a single-mode quantized light field. To gain a better understanding of light-matter interaction, it is thus necessary to explore the phase-factor-dependent physics in such a system. In this report, we consider the collective interaction between degenerate V-type three-level particles and a single-mode quantized light field, whose different components are labeled by different phase factors. We mainly establish an important relation between the phase factors and the symmetry or symmetry-broken physics. Specifically, we find that the phase factors affect dramatically the system symmetry. When these symmetries are breaking separately, rich quantum phases emerge. Finally, we propose a possible scheme to experimentally probe the predicted physics of our model. Our work provides a way to explore phase-factor-induced nontrivial physics by introducing additional particle levels.

Thermal Vibrational Convection in a Two-phase Stratified Liquid

NASA Technical Reports Server (NTRS)

Chang, Qingming; Alexander, J. Iwan D.

2007-01-01

The response of a two-phase stratified liquid system subject to a vibration parallel to an imposed temperature gradient is analyzed using a hybrid thermal lattice Boltzmann method (HTLB). The vibrations considered correspond to sinusoidal translations of a rigid cavity at a fixed frequency. The layers are thermally and mechanically coupled. Interaction between gravity-induced and vibration-induced thermal convection is studied. The ability of applied vibration to enhance the flow, heat transfer and interface distortion is investigated. For the range of conditions investigated, the results reveal that the effect of vibrational Rayleigh number and vibrational frequency on a two-phase stratified fluid system is much different than that for a single-phase fluid system. Comparisons of the response of a two-phase stratified fluid system with a single-phase fluid system are discussed.

Broadband microwave photonic fully tunable filter using a single heterogeneously integrated III-V/SOI-microdisk-based phase shifter.

PubMed

Lloret, Juan; Morthier, Geert; Ramos, Francisco; Sales, Salvador; Van Thourhout, Dries; Spuesens, Thijs; Olivier, Nicolas; Fédéli, Jean-Marc; Capmany, José

2012-05-07

A broadband microwave photonic phase shifter based on a single III-V microdisk resonator heterogeneously integrated on and coupled to a nanophotonic silicon-on-insulator waveguide is reported. The phase shift tunability is accomplished by modifying the effective index through carrier injection. A comprehensive semi-analytical model aiming at predicting its behavior is formulated and confirmed by measurements. Quasi-linear and continuously tunable 2π phase shifts at radiofrequencies greater than 18 GHz are experimentally demonstrated. The phase shifter performance is also evaluated when used as a key element in tunable filtering schemes. Distortion-free and wideband filtering responses with a tuning range of ~100% over the free spectral range are obtained.

Effect of a High Magnetic Field on γ' Phase for Ni-Based Single Crystal Superalloy During Directional Solidification

NASA Astrophysics Data System (ADS)

Xuan, Weidong; Lan, Jian; Zhao, Dengke; Li, Chuanjun; Shang, Xingfu; Zhong, Yunbo; Li, Xi; Ren, Zhongming

2018-05-01

The effect of a high magnetic field on the γ' phase of Ni-based single crystal superalloy during directional solidification is investigated experimentally. The results clearly indicate that the magnetic field significantly reduces the γ' phase size. Further, the quenching experiment is carried out, and the results found that the length of mushy zone is obviously decreased under a high magnetic field. Based on both experimental results and nucleation mechanism, it is found that the decrease of γ' phase size should be attributed to the fact that a high magnetic field causes the increase of temperature gradient in front of solid/liquid interface and leads to the increase of undercooling of γ' phase.

Solid-state carrier-envelope phase stabilization via quantum interference control of injected photocurrents.

PubMed

Roos, P A; Li, Xiaoqin; Smith, R P; Pipis, Jessica A; Fortier, T M; Cundiff, S T

2005-04-01

We demonstrate carrier-envelope phase stabilization of a mode-locked Ti:sapphire laser by use of quantum interference control of injected photocurrents in a semiconductor. No harmonic generation is required for this stabilization technique. Instead, interference between coexisting single- and two-photon absorption pathways in the semiconductor provides a phase comparison between different spectral components. The phase comparison, and the detection of the photocurrent that it produces, both occur within a single low-temperature-grown gallium arsenide sample. The carrier-envelope offset beat note fidelity is 30 dB in a 10-kHz resolution bandwidth. The out-of-loop phase-noise level is essentially identical to the best previous measurements with the standard self-referencing technique.

Laser pyrolysis fabrication of ferromagnetic gamma'-Fe4N and FeC nanoparticles

NASA Technical Reports Server (NTRS)

Grimes, C. A.; Qian, D.; Dickey, E. C.; Allen, J. L.; Eklund, P. C.

2000-01-01

Using the laser pyrolysis method, single phase gamma'-Fe4N nanoparticles were prepared by a two step method involving preparation of nanoscale iron oxide and a subsequent gas-solid nitridation reaction. Single phase Fe3C and Fe7C3 could be prepared by laser pyrolysis from Fe(CO)5 and 3C2H4 directly. Characterization techniques such as XRD, TEM and vibrating sample magnetometer were used to measure phase structure, particle size and magnetic properties of these nanoscale nitride and carbide particles. c2000 American Journal of Physics.

A MPPT Algorithm Based PV System Connected to Single Phase Voltage Controlled Grid

NASA Astrophysics Data System (ADS)

Sreekanth, G.; Narender Reddy, N.; Durga Prasad, A.; Nagendrababu, V.

2012-10-01

Future ancillary services provided by photovoltaic (PV) systems could facilitate their penetration in power systems. In addition, low-power PV systems can be designed to improve the power quality. This paper presents a single-phase PV systemthat provides grid voltage support and compensation of harmonic distortion at the point of common coupling thanks to a repetitive controller. The power provided by the PV panels is controlled by a Maximum Power Point Tracking algorithm based on the incremental conductance method specifically modified to control the phase of the PV inverter voltage. Simulation and experimental results validate the presented solution.

Noise-cancelling quadrature magnetic position, speed and direction sensor

DOEpatents

Preston, Mark A.; King, Robert D.

1996-01-01

An array of three magnetic sensors in a single package is employed with a single bias magnet for sensing shaft position, speed and direction of a motor in a high magnetic noise environment. Two of the three magnetic sensors are situated in an anti-phase relationship (i.e., 180.degree. out-of-phase) with respect to the relationship between the other of the two sensors and magnetically salient target, and the third magnetic sensor is situated between the anti-phase sensors. The result is quadrature sensing with noise immunity for accurate relative position, speed and direction measurements.

Holonomic Quantum Control by Coherent Optical Excitation in Diamond.

PubMed

Zhou, Brian B; Jerger, Paul C; Shkolnikov, V O; Heremans, F Joseph; Burkard, Guido; Awschalom, David D

2017-10-06

Although geometric phases in quantum evolution are historically overlooked, their active control now stimulates strategies for constructing robust quantum technologies. Here, we demonstrate arbitrary single-qubit holonomic gates from a single cycle of nonadiabatic evolution, eliminating the need to concatenate two separate cycles. Our method varies the amplitude, phase, and detuning of a two-tone optical field to control the non-Abelian geometric phase acquired by a nitrogen-vacancy center in diamond over a coherent excitation cycle. We demonstrate the enhanced robustness of detuned gates to excited-state decoherence and provide insights for optimizing fast holonomic control in dissipative quantum systems.

Thermodynamic Analysis and Growth of Zirconium Carbide by Chemical Vapor Deposition

NASA Astrophysics Data System (ADS)

Wei, Sun; Hua, Hao Zheng; Xiang, Xiong

Equilibrium calculations were used to optimize conditions for the chemical vapor deposition of zirconium carbide from zirconium halide + CxHy+H2+Ar system. The results show the CVD-ZrC phase diagram is divided into ZrC+C, ZrC and ZrC+Zr zones by C, Zr generating lines. For the same mole of ZrCl4 reactant, it needs higher concentration of CH4 to generate single ZrC phase than that of C3H6. Using these calculations as a guide, single-phase cubic zirconium carbide coatings were deposited onto graphite substrate.

Structure of interfaces at phase coexistence. Theory and numerics

NASA Astrophysics Data System (ADS)

Delfino, Gesualdo; Selke, Walter; Squarcini, Alessio

2018-05-01

We compare results of the exact field theory of phase separation in two dimensions with Monte Carlo simulations for the q-state Potts model with boundary conditions producing an interfacial region separating two pure phases. We confirm in particular the theoretical predictions that below critical temperature the surplus of non-boundary colors appears in drops along a single interface, while for q  >  4 at critical temperature there is formation of two interfaces enclosing a macroscopic disordered layer. These qualitatively different structures of the interfacial region can be discriminated through a measurement at a single point for different system sizes.

A Riemann solver for single-phase and two-phase shallow flow models based on relaxation. Relations with Roe and VFRoe solvers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pelanti, Marica, E-mail: Marica.Pelanti@ens.f; Bouchut, Francois, E-mail: francois.bouchut@univ-mlv.f; Mangeney, Anne, E-mail: mangeney@ipgp.jussieu.f

2011-02-01

We present a Riemann solver derived by a relaxation technique for classical single-phase shallow flow equations and for a two-phase shallow flow model describing a mixture of solid granular material and fluid. Our primary interest is the numerical approximation of this two-phase solid/fluid model, whose complexity poses numerical difficulties that cannot be efficiently addressed by existing solvers. In particular, we are concerned with ensuring a robust treatment of dry bed states. The relaxation system used by the proposed solver is formulated by introducing auxiliary variables that replace the momenta in the spatial gradients of the original model systems. The resultingmore » relaxation solver is related to Roe solver in that its Riemann solution for the flow height and relaxation variables is formally computed as Roe's Riemann solution. The relaxation solver has the advantage of a certain degree of freedom in the specification of the wave structure through the choice of the relaxation parameters. This flexibility can be exploited to handle robustly vacuum states, which is a well known difficulty of standard Roe's method, while maintaining Roe's low diffusivity. For the single-phase model positivity of flow height is rigorously preserved. For the two-phase model positivity of volume fractions in general is not ensured, and a suitable restriction on the CFL number might be needed. Nonetheless, numerical experiments suggest that the proposed two-phase flow solver efficiently models wet/dry fronts and vacuum formation for a large range of flow conditions. As a corollary of our study, we show that for single-phase shallow flow equations the relaxation solver is formally equivalent to the VFRoe solver with conservative variables of Gallouet and Masella [T. Gallouet, J.-M. Masella, Un schema de Godunov approche C.R. Acad. Sci. Paris, Serie I, 323 (1996) 77-84]. The relaxation interpretation allows establishing positivity conditions for this VFRoe method.« less

Interference Confocal Microscope Integrated with Spatial Phase Shifter.

PubMed

Wang, Weibo; Gu, Kang; You, Xiaoyu; Tan, Jiubin; Liu, Jian

2016-08-24

We present an interference confocal microscope (ICM) with a new single-body four-step simultaneous phase-shifter device designed to obtain high immunity to vibration. The proposed ICM combines the respective advantages of simultaneous phase shifting interferometry and bipolar differential confocal microscopy to obtain high axis resolution, large dynamic range, and reduce the sensitivity to vibration and reflectance disturbance seamlessly. A compact single body spatial phase shifter is added to capture four phase-shifted interference signals simultaneously without time delay and construct a stable and space-saving simplified interference confocal microscope system. The test result can be obtained by combining the interference phase response and the bipolar property of differential confocal microscopy without phase unwrapping. Experiments prove that the proposed microscope is capable of providing stable measurements with 1 nm of axial depth resolution for either low- or high-numerical aperture objective lenses.

Permanent split capacitor single phase electric motor system

DOEpatents

Kirschbaum, H.S.

1984-08-14

A permanent split capacitor single phase electric motor achieves balanced operation at more than one operating point by adjusting the voltage supplied to the main and auxiliary windings and adjusting the capacitance in the auxiliary winding circuit. An intermediate voltage tap on an autotransformer supplies voltage to the main winding for low speed operation while a capacitive voltage divider is used to adjust the voltage supplied to the auxiliary winding for low speed operation. 4 figs.

High performance mode locking characteristics of single section quantum dash lasers.

PubMed

Rosales, Ricardo; Murdoch, S G; Watts, R T; Merghem, K; Martinez, Anthony; Lelarge, Francois; Accard, Alain; Barry, L P; Ramdane, Abderrahim

2012-04-09

Mode locking features of single section quantum dash based lasers are investigated. Particular interest is given to the static spectral phase profile determining the shape of the mode locked pulses. The phase profile dependence on cavity length and injection current is experimentally evaluated, demonstrating the possibility of efficiently using the wide spectral bandwidth exhibited by these quantum dash structures for the generation of high peak power sub-picosecond pulses with low radio frequency linewidths.

SPM and XPM crosstalk in WDM systems with DRA: Channel spacing and attenuation effects

NASA Astrophysics Data System (ADS)

Morsy, Emadeldeen; Fayed, Heba A.; Abd El Aziz, Ahmed; Aly, Moustafa H.

2018-06-01

This paper presents a theoretical analysis of a closed formula for nonlinear crosstalk due to self-phase modulation (SPM) and cross phase modulation (XPM) in wavelength division multiplexing (WDM) systems. The influence of channel spacing and attenuation on the system behavior is modeled and investigated. The system under consideration is a standard single-mode fiber (SSMF) with a single-span distributed Raman amplifier (DRA) and is operating at 100 Gbps.

Low-Cost, Single-Frequency Sources for Spectroscopy using Conventional Fabry-Perot Diode Lasers

NASA Technical Reports Server (NTRS)

Duerksen, Gary L.; Krainak, Michael A.

1999-01-01

Commercial (uncoated) Fabry-Perot laser diodes are converted to single-frequency spectroscopy sources by passively locking the laser frequency to the band edge of a fiber Bragg grating, which phase-locks the laser oscillations through self-injection seeding.

Low-Cost, Single-Frequency Sources for Spectroscopy Using Conventional Fabry-Perot Diode Lasers

NASA Technical Reports Server (NTRS)

Krainak, Michael A.; Duerksen, Gary L.

1999-01-01

Commercial (uncoated) Fabry-Perot laser diodes are converted to single-frequency spectroscopy sources by passively locking the laser frequency to the band edge of a fiber Bragg grating, which phase-locks the laser oscillations through self-injection seeding.

Standards for single span prefabricated bridges : phase I - concept development.

DOT National Transportation Integrated Search

2014-07-01

In coordination with a Technical Advisory Committee (TAC) consisting of County : Engineers and Iowa DOT representatives, the Iowa DOT has proposed to develop a set : of standards for a single span prefabricated bridge system for use on the local road...

Layover and shadow detection based on distributed spaceborne single-baseline InSAR

NASA Astrophysics Data System (ADS)

Huanxin, Zou; Bin, Cai; Changzhou, Fan; Yun, Ren

2014-03-01

Distributed spaceborne single-baseline InSAR is an effective technique to get high quality Digital Elevation Model. Layover and Shadow are ubiquitous phenomenon in SAR images because of geometric relation of SAR imaging. In the signal processing of single-baseline InSAR, the phase singularity of Layover and Shadow leads to the phase difficult to filtering and unwrapping. This paper analyzed the geometric and signal model of the Layover and Shadow fields. Based on the interferometric signal autocorrelation matrix, the paper proposed the signal number estimation method based on information theoretic criteria, to distinguish Layover and Shadow from normal InSAR fields. The effectiveness and practicability of the method proposed in the paper are validated in the simulation experiments and theoretical analysis.

Single-shot digital holography by use of the fractional Talbot effect.

PubMed

Martínez-León, Lluís; Araiza-E, María; Javidi, Bahram; Andrés, Pedro; Climent, Vicent; Lancis, Jesús; Tajahuerce, Enrique

2009-07-20

We present a method for recording in-line single-shot digital holograms based on the fractional Talbot effect. In our system, an image sensor records the interference between the light field scattered by the object and a properly codified parallel reference beam. A simple binary two-dimensional periodic grating is used to codify the reference beam generating a periodic three-step phase distribution over the sensor plane by fractional Talbot effect. This provides a method to perform single-shot phase-shifting interferometry at frame rates only limited by the sensor capabilities. Our technique is well adapted for dynamic wavefront sensing applications. Images of the object are digitally reconstructed from the digital hologram. Both computer simulations and experimental results are presented.

Rapid calculation of acoustic fields from arbitrary continuous-wave sources.

PubMed

Treeby, Bradley E; Budisky, Jakub; Wise, Elliott S; Jaros, Jiri; Cox, B T

2018-01-01

A Green's function solution is derived for calculating the acoustic field generated by phased array transducers of arbitrary shape when driven by a single frequency continuous wave excitation with spatially varying amplitude and phase. The solution is based on the Green's function for the homogeneous wave equation expressed in the spatial frequency domain or k-space. The temporal convolution integral is solved analytically, and the remaining integrals are expressed in the form of the spatial Fourier transform. This allows the acoustic pressure for all spatial positions to be calculated in a single step using two fast Fourier transforms. The model is demonstrated through several numerical examples, including single element rectangular and spherically focused bowl transducers, and multi-element linear and hemispherical arrays.

Narrow linewidth power scaling and phase stabilization of 2-μm thulium fiber lasers

NASA Astrophysics Data System (ADS)

Goodno, Gregory D.; Book, Lewis D.; Rothenberg, Joshua E.; Weber, Mark E.; Benjamin Weiss, S.

2011-11-01

Thulium-doped fiber lasers (TFLs) emitting retina-safe 2-μm wavelengths offer substantial power-scaling advantages over ytterbium-doped fiber lasers for narrow linewidth, single-mode operation. This article reviews the design and performance of a pump-limited, 600 W, single-mode, single-frequency TFL amplifier chain that balances thermal limitations against those arising from stimulated Brillouin scattering (SBS). A simple analysis of thermal and SBS limits is anchored with measurements on kilowatt class Tm and Yb fiber lasers to highlight the scaling advantage of Tm for narrow linewidth operation. We also report recent results on active phase-locking of a TFL amplifier to an optical reference as a precursor to further parallel scaling via coherent beam combining.

Spatial layout affects speed discrimination

NASA Technical Reports Server (NTRS)

Verghese, P.; Stone, L. S.

1997-01-01

We address a surprising result in a previous study of speed discrimination with multiple moving gratings: discrimination thresholds decreased when the number of stimuli was increased, but remained unchanged when the area of a single stimulus was increased [Verghese & Stone (1995). Vision Research, 35, 2811-2823]. In this study, we manipulated the spatial- and phase relationship between multiple grating patches to determine their effect on speed discrimination thresholds. In a fusion experiment, we merged multiple stimulus patches, in stages, into a single patch. Thresholds increased as the patches were brought closer and their phase relationship was adjusted to be consistent with a single patch. Thresholds increased further still as these patches were fused into a single patch. In a fission experiment, we divided a single large patch into multiple patches by superimposing a cross with luminance equal to that of the background. Thresholds decreased as the large patch was divided into quadrants and decreased further as the quadrants were maximally separated. However, when the cross luminance was darker than the background, it was perceived as an occluder and thresholds, on average, were unchanged from that for the single large patch. A control experiment shows that the observed trend in discrimination thresholds is not due to the differences in perceived speed of the stimuli. These results suggest that the parsing of the visual image into entities affects the combination of speed information across space, and that each discrete entity effectively provides a single independent estimate of speed.

Optics & Opto-Electronic Systems

DTIC Science & Technology

1988-06-01

its reflection by the 13 cavity boundaries, and its reabsorption by the atom. Multimode corrections to the single-mode Jaynes - Cummings model are...walls. Transients in the Micromaser C. R. Stroud, Jr. The Jaynes - Cummings model of a single two-lev3l atom interacting with a single field mode of a...increasing laser intensity and to be as large as 22 bits/sec. A standard model of self- pumped phase conjugation due to four- wave mixing has been

Synthesis of a mesoporous single crystal Ga2O3 nanoplate with improved photoluminescence and high sensitivity in detecting CO.

PubMed

Yan, Shicheng; Wan, Lijuan; Li, Zhaosheng; Zhou, Yong; Zou, Zhigang

2010-09-14

A new approach is proposed to synthesize a mesoporous single crystal Ga(2)O(3) nanoplate by heating a single crystal nanoplate of GaOOH, which involves an ion exchange between KGaO(2) and CH(3)COOH at room temperature for the formation of GaOOH and pseudomorphic and topotactic phase transformation from GaOOH to Ga(2)O(3).

Automated Support for da Vinci Surgical System

DTIC Science & Technology

2011-05-01

MScore, which provides objective assessment measuring robotic surgery skills across all computed metrics (Figure 7). In addition to viewing single ...holding an object. Data Collection & Analysis (Task 5)  Preliminary Experiments  During the first phase of data collection, a single performance of...a single task (anastomosis) trial was recorded from six different users – three each for the da Vinci and the dV-Trainer platforms. On each platform

Ni-Mn-Ga Single Crystal Exhibiting Multiple Magnetic Shape Memory Effects

NASA Astrophysics Data System (ADS)

Heczko, Oleg; Veřtát, Petr; Vronka, Marek; Kopecky, Vít; Perevertov, Oleksiy

2016-09-01

Both magnetically induced phase transformation and magnetically induced reorientation (MIR) effects were observed in one Ni50Mn28Ga22 single crystal sample by direct measurement of the magnetic field-induced strain. We investigated various twinning microstructures ranged from single twin interface to fine twinning and crossing twins to evaluate what controls the apparent twinning stress crucial for MIR. The main challenges for the applications of these effects are outlined.

Comparison of vapor formation of water at the solid/water interface to colloidal solutions using optically excited gold nanostructures.

PubMed

Baral, Susil; Green, Andrew J; Livshits, Maksim Y; Govorov, Alexander O; Richardson, Hugh H

2014-02-25

The phase transformation properties of liquid water to vapor is characterized by optical excitation of the lithographically fabricated single gold nanowrenches and contrasted to the phase transformation properties of gold nanoparticles located and optically excited in a bulk solution system [two and three dimensions]. The 532 nm continuous wave excitation of a single gold nanowrench results in superheating of the water to the spinodal decomposition temperature of 580 ± 20 K with bubble formation below the spinodal decomposition temperature being a rare event. Between the spinodal decomposition temperature and the boiling point liquid water is trapped into a metastable state because a barrier to vapor nucleation exists that must be overcome before the thermodynamically stable state is realized. The phase transformation for an optically heated single gold nanowrench is different from the phase transformation of optically excited colloidal gold nanoparticles solution where collective heating effects dominates and leads to the boiling of the solution exactly at the boiling point. In the solution case, the optically excited ensemble of nanoparticles collectively raises the ambient temperature of water to the boiling point where liquid is converted into vapor. The striking difference in the boiling properties of the single gold nanowrench and the nanoparticle solution system can be explained in terms of the vapor-nucleation mechanism, the volume of the overheated liquid, and the collective heating effect. The interpretation of the observed regimes of heating and vaporization is consistent with our theoretical modeling. In particular, we explain with our theory why the boiling with the collective heating in a solution requires 3 orders of magnitude less intensity compared to the case of optically driven single nanowrench.

Zr 2Ir 6B with an eightfold superstructure of the cubic perovskite-like boride ZrIr 3B 0.5: Synthesis, crystal structure and bonding analysis

NASA Astrophysics Data System (ADS)

Hermus, Martin; Fokwa, Boniface P. T.

2010-04-01

Single phase powder samples and single crystals of Zr 2Ir 6B were successfully synthesized by arc-melting the elements in a water-cooled copper crucible under an argon atmosphere. Superstructure reflections were observed both on powder and on single crystal diffraction data, leading to an eightfold superstructure of ZrIr 3B x phase. The new phase, which has a metallic luster, crystallizes in space group Fm3¯m (no. 225) with the lattice parameters a=7.9903(4) Å, V=510.14(4) Å 3. Its crystal structure was refined on the basis of powder as well as single crystal data. The single crystal refinement converged to R1=0.0239 and w R2=0.0624 for all 88 unique reflections and 6 parameters. Zr 2Ir 6B is isotypic to Ti 2Rh 6B and its structure can be described as a defect double perovskite, A2BB' O6, where the A site is occupied by zirconium, the B site by boron, the O site by iridium but the B' site is vacant, leading to the formation of empty and boron-filled octahedral Ir 6 clusters. According to the result of tight-binding electronic structure calculations, Ir-B and Ir-Zr interactions are mainly responsible for the structural stability of the phase. According to COHP bonding analysis, the strongest bonding occurs for the Ir-B contacts, and the Ir-Ir bonding within the empty clusters is two times stronger than that in the BIr 6 octahedra.

Resolution of Conflicting Signals at the Single-Cell Level in the Regulation of Cyanobacterial Photosynthesis and Nitrogen Fixation.

PubMed

Mohr, Wiebke; Vagner, Tomas; Kuypers, Marcel M M; Ackermann, Martin; Laroche, Julie

2013-01-01

Unicellular, diazotrophic cyanobacteria temporally separate dinitrogen (N2) fixation and photosynthesis to prevent inactivation of the nitrogenase by oxygen. This temporal segregation is regulated by a circadian clock with oscillating activities of N2 fixation in the dark and photosynthesis in the light. On the population level, this separation is not always complete, since the two processes can overlap during transitions from dark to light. How do single cells avoid inactivation of nitrogenase during these periods? One possibility is that phenotypic heterogeneity in populations leads to segregation of the two processes. Here, we measured N2 fixation and photosynthesis of individual cells using nanometer-scale secondary ion mass spectrometry (nanoSIMS) to assess both processes in a culture of the unicellular, diazotrophic cyanobacterium Crocosphaera watsonii during a dark-light and a continuous light phase. We compared single-cell rates with bulk rates and gene expression profiles. During the regular dark and light phases, C. watsonii exhibited the temporal segregation of N2 fixation and photosynthesis commonly observed. However, N2 fixation and photosynthesis were concurrently measurable at the population level during the subjective dark phase in which cells were kept in the light rather than returned to the expected dark phase. At the single-cell level, though, cells discriminated against either one of the two processes. Cells that showed high levels of photosynthesis had low nitrogen fixing activities, and vice versa. These results suggest that, under ambiguous environmental signals, single cells discriminate against either photosynthesis or nitrogen fixation, and thereby might reduce costs associated with running incompatible processes in the same cell.

Resolution of Conflicting Signals at the Single-Cell Level in the Regulation of Cyanobacterial Photosynthesis and Nitrogen Fixation

PubMed Central

Mohr, Wiebke; Vagner, Tomas; Kuypers, Marcel M. M.; Ackermann, Martin; LaRoche, Julie

2013-01-01

Unicellular, diazotrophic cyanobacteria temporally separate dinitrogen (N2) fixation and photosynthesis to prevent inactivation of the nitrogenase by oxygen. This temporal segregation is regulated by a circadian clock with oscillating activities of N2 fixation in the dark and photosynthesis in the light. On the population level, this separation is not always complete, since the two processes can overlap during transitions from dark to light. How do single cells avoid inactivation of nitrogenase during these periods? One possibility is that phenotypic heterogeneity in populations leads to segregation of the two processes. Here, we measured N2 fixation and photosynthesis of individual cells using nanometer-scale secondary ion mass spectrometry (nanoSIMS) to assess both processes in a culture of the unicellular, diazotrophic cyanobacterium Crocosphaera watsonii during a dark-light and a continuous light phase. We compared single-cell rates with bulk rates and gene expression profiles. During the regular dark and light phases, C. watsonii exhibited the temporal segregation of N2 fixation and photosynthesis commonly observed. However, N2 fixation and photosynthesis were concurrently measurable at the population level during the subjective dark phase in which cells were kept in the light rather than returned to the expected dark phase. At the single-cell level, though, cells discriminated against either one of the two processes. Cells that showed high levels of photosynthesis had low nitrogen fixing activities, and vice versa. These results suggest that, under ambiguous environmental signals, single cells discriminate against either photosynthesis or nitrogen fixation, and thereby might reduce costs associated with running incompatible processes in the same cell. PMID:23805199

Atom-atom entanglement by single-photon detection.

PubMed

Slodička, L; Hétet, G; Röck, N; Schindler, P; Hennrich, M; Blatt, R

2013-02-22

A scheme for entangling distant atoms is realized, as proposed in the seminal paper by [C. Cabrillo et al., Phys. Rev. A 59, 1025 (1999)]. The protocol is based on quantum interference and detection of a single photon scattered from two effectively one meter distant laser cooled and trapped atomic ions. The detection of a single photon heralds entanglement of two internal states of the trapped ions with high rate and with a fidelity limited mostly by atomic motion. Control of the entangled state phase is demonstrated by changing the path length of the single-photon interferometer.

An Overview of the Effects of Alloying Elements on the Properties of Lightweight Fe-(15-35) Mn-(5-12) Al-(0.3-1.2) C Steel

NASA Astrophysics Data System (ADS)

Xing, Jia; Wei, Yinghui; Hou, Lifeng

2018-06-01

In this review, the influences of alloying elements on the phase constitution, density, and stacking fault energy of Fe-(15-35) Mn-(5-12) Al-(0.3-1.2) C lightweight steel are discussed. The mechanical properties of austenite single-phase and austenite-ferrite dual-phase Fe-Mn-Al-C steels processed by different procedures are also statistically analyzed. The austenite single-phase steel was found to possess superior strength and plasticity. Three reasonable explanations for the mechanism of plastic deformation are presented, namely, shear band-induced plasticity, microband-induced plasticity, and slip band refinement-induced plasticity.

Universal holonomic single quantum gates over a geometric spin with phase-modulated polarized light.

PubMed

Ishida, Naoki; Nakamura, Takaaki; Tanaka, Touta; Mishima, Shota; Kano, Hiroki; Kuroiwa, Ryota; Sekiguchi, Yuhei; Kosaka, Hideo

2018-05-15

We demonstrate universal non-adiabatic non-abelian holonomic single quantum gates over a geometric electron spin with phase-modulated polarized light and 93% average fidelity. This allows purely geometric rotation around an arbitrary axis by any angle defined by light polarization and phase using a degenerate three-level Λ-type system in a negatively charged nitrogen-vacancy center in diamond. Since the control light is completely resonant to the ancillary excited state, the demonstrated holonomic gate not only is fast with low power, but also is precise without the dynamical phase being subject to control error and environmental noise. It thus allows pulse shaping for further fidelity.

Ultra-low noise dual-frequency VECSEL at telecom wavelength using fully correlated pumping.

PubMed

Liu, Hui; Gredat, Gregory; De, Syamsundar; Fsaifes, Ihsan; Ly, Aliou; Vatré, Rémy; Baili, Ghaya; Bouchoule, Sophie; Goldfarb, Fabienne; Bretenaker, Fabien

2018-04-15

An ultra-low intensity and beatnote phase noise dual-frequency vertical-external-cavity surface-emitting laser is built at telecom wavelength. The pump laser is realized by polarization combining two single-mode fibered laser diodes in a single-mode fiber, leading to a 100% in-phase correlation of the pump noises for the two modes. The relative intensity noise is lower than -140  dB/Hz, and the beatnote phase noise is suppressed by 30 dB, getting close to the spontaneous emission limit. The role of the imperfect cancellation of the thermal effect resulting from unbalanced pumping of the two modes in the residual phase noise is evidenced.

EIT-based all-optical switching and cross-phase modulation under the influence of four-wave mixing.

PubMed

Lee, Meng-Jung; Chen, Yi-Hsin; Wang, I-Chung; Yu, Ite A

2012-05-07

All-optical switching (AOS) or cross-phase modulation (XPM) based on the effect of electromagnetically induced transparency (EIT) makes one photon switched or phase-modulated by another possible. The existence of four-wave mixing (FWM) process greatly diminishes the switching or phase-modulation efficiency and hinders the single-photon operation. We proposed and experimentally demonstrated an idea that with an optimum detuning the EIT-based AOS can be completely intact even under the influence of FWM. The results of the work can be directly applied to the EIT-based XPM. Our work makes the AOS and XPM schemes more flexible and the single-photon operation possible in FWM-allowed systems.

An Overview of the Effects of Alloying Elements on the Properties of Lightweight Fe-(15-35) Mn-(5-12) Al-(0.3-1.2) C Steel

NASA Astrophysics Data System (ADS)

Xing, Jia; Wei, Yinghui; Hou, Lifeng

2018-04-01

In this review, the influences of alloying elements on the phase constitution, density, and stacking fault energy of Fe-(15-35) Mn-(5-12) Al-(0.3-1.2) C lightweight steel are discussed. The mechanical properties of austenite single-phase and austenite-ferrite dual-phase Fe-Mn-Al-C steels processed by different procedures are also statistically analyzed. The austenite single-phase steel was found to possess superior strength and plasticity. Three reasonable explanations for the mechanism of plastic deformation are presented, namely, shear band-induced plasticity, microband-induced plasticity, and slip band refinement-induced plasticity.

Shock-Induced phase transition of single crystal copper

NASA Astrophysics Data System (ADS)

Neogi, Anupam; Mitra, Nilanjan

2017-05-01

We have carried out a series of multi-million atoms non-equilibrium molecular dynamics simulations to investigate the effect of crystal orientation over the shock induced plasticity and phase transformation in single crystal copper. Crystallographic orientation of [100], [110] and [111] has been studied for various intensity of shock ranging from 1.0 km/s to 3.0 km/s. During shock wave propagation along <100> and <110>, a FCC-to-BCC phase transformation has been observed to occur behind the shock front at higher intensity of shock. Nucleated body centered phase is identified through common neighbor analysis, polyhedral matching template method, radial distribution function and also from the energetic of the particles.

Features of structure formation in the low modulus quasi-single crystal from Zr-25%Nb alloy at cold rolling

NASA Astrophysics Data System (ADS)

Isaenkova, M.; Perlovich, Yu.; Fesenko, V.; Babich, Y.; Zaripova, M.; Krapivka, N.

2018-05-01

The paper presents the results of investigation of the regularities of the structure and texture formation during rolling of single crystals of Zr-25%Nb alloy differing in their initial orientations relative to the external principal directions in the rolled plate: normal (ND) and rolling directions (RD). The features of rolled single crystals with initial orientations of planes {001}, {011} or {111} parallel to the rolling plane and different crystallographic directions along RD are considered. A comparison of the peculiarities of plastic deformation in a polycrystalline alloy of the same composition is made. For the samples studied, a decrease in the lattice parameter of the β-phase has been recorded, the minimum of the parameter being observed for different degrees of deformation, varying from 20 to 50%. Observed decrease in the unit cell parameter can be connected with the precipitation of the α(α')-Zr phase from the deformed nonequilibrium β-phase of the Zr-25%Nb alloy, i.e. change in the composition of the solid solution. Distributions of the increase in the dimensions of the deformed single crystal along RD and the transverse direction (TD) with its deformation up to 30% in thickness, which indicate the anisotropy of the plasticity of single crystals during their rolling, are constructed on stereographic projection. It is shown, that the deformation of single crystals occurs practically without increasing of their dimensions in the <110> direction with a total thickness deformation of up to 30%. Direction <110> is characterized by maximum hardening (microhardness) with indentation along it, which causes low plasticity of deformed and annealed foils from Zr-25%Nb alloy at the stretching along and across RD, that is connected with the features of their crystallographic texture.

Temporal and Spatial Evolution Characteristics of Disturbance Wave in a Hypersonic Boundary Layer due to Single-Frequency Entropy Disturbance

PubMed Central

Lv, Hongqing; Shi, Jianqiang

2014-01-01

By using a high-order accurate finite difference scheme, direct numerical simulation of hypersonic flow over an 8° half-wedge-angle blunt wedge under freestream single-frequency entropy disturbance is conducted; the generation and the temporal and spatial nonlinear evolution of boundary layer disturbance waves are investigated. Results show that, under the freestream single-frequency entropy disturbance, the entropy state of boundary layer is changed sharply and the disturbance waves within a certain frequency range are induced in the boundary layer. Furthermore, the amplitudes of disturbance waves in the period phase are larger than that in the response phase and ablation phase and the frequency range in the boundary layer in the period phase is narrower than that in these two phases. In addition, the mode competition, dominant mode transformation, and disturbance energy transfer exist among different modes both in temporal and in spatial evolution. The mode competition changes the characteristics of nonlinear evolution of the unstable waves in the boundary layer. The development of the most unstable mode along streamwise relies more on the motivation of disturbance waves in the upstream than that of other modes on this motivation. PMID:25143983

Temporal and spatial evolution characteristics of disturbance wave in a hypersonic boundary layer due to single-frequency entropy disturbance.

PubMed

Wang, Zhenqing; Tang, Xiaojun; Lv, Hongqing; Shi, Jianqiang

2014-01-01

By using a high-order accurate finite difference scheme, direct numerical simulation of hypersonic flow over an 8° half-wedge-angle blunt wedge under freestream single-frequency entropy disturbance is conducted; the generation and the temporal and spatial nonlinear evolution of boundary layer disturbance waves are investigated. Results show that, under the freestream single-frequency entropy disturbance, the entropy state of boundary layer is changed sharply and the disturbance waves within a certain frequency range are induced in the boundary layer. Furthermore, the amplitudes of disturbance waves in the period phase are larger than that in the response phase and ablation phase and the frequency range in the boundary layer in the period phase is narrower than that in these two phases. In addition, the mode competition, dominant mode transformation, and disturbance energy transfer exist among different modes both in temporal and in spatial evolution. The mode competition changes the characteristics of nonlinear evolution of the unstable waves in the boundary layer. The development of the most unstable mode along streamwise relies more on the motivation of disturbance waves in the upstream than that of other modes on this motivation.

Crystal viscoplasticity model for the creep-fatigue interactions in single-crystal Ni-base superalloy CMSX-8

DOE Office of Scientific and Technical Information (OSTI.GOV)

Estrada Rodas, Ernesto A.; Neu, Richard W.

A crystal viscoplasticity (CVP) model for the creep-fatigue interactions of nickel-base superalloy CMSX-8 is proposed. At the microstructure scale of relevance, the superalloys are a composite material comprised of a γ phase and a γ' strengthening phase with unique deformation mechanisms that are highly dependent on temperature. Considering the differences in the deformation of the individual material phases is paramount to predicting the deformation behavior of superalloys at a wide range of temperatures. In this work, we account for the relevant deformation mechanisms that take place in both material phases by utilizing two additive strain rates to model the deformationmore » on each material phase. The model is capable of representing the creep-fatigue interactions in single-crystal superalloys for realistic 3-dimensional components in an Abaqus User Material Subroutine (UMAT). Using a set of material parameters calibrated to superalloy CMSX-8, the model predicts creep-fatigue, fatigue and thermomechanical fatigue behavior of this single-crystal superalloy. In conclusion, a sensitivity study of the material parameters is done to explore the effect on the deformation due to changes in the material parameters relevant to the microstructure.« less

Crystal viscoplasticity model for the creep-fatigue interactions in single-crystal Ni-base superalloy CMSX-8

DOE PAGES

Estrada Rodas, Ernesto A.; Neu, Richard W.

2017-09-11

A crystal viscoplasticity (CVP) model for the creep-fatigue interactions of nickel-base superalloy CMSX-8 is proposed. At the microstructure scale of relevance, the superalloys are a composite material comprised of a γ phase and a γ' strengthening phase with unique deformation mechanisms that are highly dependent on temperature. Considering the differences in the deformation of the individual material phases is paramount to predicting the deformation behavior of superalloys at a wide range of temperatures. In this work, we account for the relevant deformation mechanisms that take place in both material phases by utilizing two additive strain rates to model the deformationmore » on each material phase. The model is capable of representing the creep-fatigue interactions in single-crystal superalloys for realistic 3-dimensional components in an Abaqus User Material Subroutine (UMAT). Using a set of material parameters calibrated to superalloy CMSX-8, the model predicts creep-fatigue, fatigue and thermomechanical fatigue behavior of this single-crystal superalloy. In conclusion, a sensitivity study of the material parameters is done to explore the effect on the deformation due to changes in the material parameters relevant to the microstructure.« less

A single-phase Ba{sub 9}Lu{sub 2}Si{sub 6}O{sub 24}:Eu{sup 2+}, Ce{sup 3+}, Mn{sup 2+} phosphor with tunable full-color emission for NUV-based white LED applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Changhua; Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201; Liu, Yongfu, E-mail: liuyongfu@nimte.ac.cn

Highlights: • A single phase Ba{sub 9}Lu{sub 2}Si{sub 6}O{sub 24}:Eu{sup 2+}, Ce{sup 3+}, Mn{sup 2+} phosphor with full-color emission was obtained by solid-state reactions. • Eu{sup 2+}, Ce{sup 3+}, and Mn{sup 2+} acts as blue, green, and red luminescence centers, respectively. • The BLS:Eu{sup 2+}, Ce{sup 3+}, Mn{sup 2+} phosphor shows a high quantum efficient of ∼62% and a good color stability. • Combining this single phosphor with a 395 nm NUV-chip, an ideal white LED with a high CRI of 85 and a CCT of 6300 K was obtained. - Abstract: We obtained a single phase BLS:Eu{sup 2+}, Ce{supmore » 3+}, Mn{sup 2+} phosphor by solid-state reactions. Eu{sup 2+}, Ce{sup 3+}, and Mn{sup 2+} gives rise to the blue, green, and red emission, respectively. The Mn{sup 2+} red emission can be effectively enhanced via energy transfers from both Eu{sup 2+} and Ce{sup 3+}. Thus a tunable full color emission from 410 to 750 nm was realized in this single phosphor. The Eu{sup 2+} → Mn{sup 2+} energy transfer mechanism was investigated by the fluorescence decay curves. This single phosphor exhibits an efficient excitation band covering from 390 to 410 nm, which matches well with the emission light of the efficient NUV chips. The optimized BLS:Eu{sup 2+}, Ce{sup 3+}, Mn{sup 2+} phosphor shows a high quantum efficient of ∼62% and a good color stability. When this single phosphor was combined with a 395 nm NUV-chip, an ideal white LED with a high color render index (CRI) of 85 and a correlated color temperature (CCT) of 6300 K was obtained. This demonstrates the promising application of the BLS:Eu{sup 2+}, Ce{sup 3+}, Mn{sup 2+} single phosphor for the NUV-based white LEDs.« less

Multi-susceptibile Single-Phased Ceramics with Both Considerable Magnetic and Dielectric Properties by Selectively Doping

PubMed Central

Liu, Chuyang; Zhang, Yujing; Jia, Jingguo; Sui, Qiang; Ma, Ning; Du, Piyi

2015-01-01

Multiferroic ceramics with extraordinary susceptibilities coexisting are vitally important for the multi-functionality and integration of electronic devices. However, multiferroic composites, as the most potential candidates, will introduce inevitable interface deficiencies and thus dielectric loss from dissimilar phases. In this study, single-phased ferrite ceramics with considerable magnetic and dielectric performances appearing simultaneously were fabricated by doping target ions in higher valence than that of Fe3+, such as Ti4+, Nb5+ and Zr4+, into BaFe12O19. In terms of charge balance, Fe3+/Fe2+ pair dipoles are produced through the substitution of Fe3+ by high-valenced ions. The electron hopping between Fe3+ and Fe2+ ions results in colossal permittivity. Whilst the single-phased ceramics doped by target ions exhibit low dielectric loss naturally due to the diminishment of interfacial polarization and still maintain typical magnetic properties. This study provides a convenient method to attain practicable materials with both outstanding magnetic and dielectric properties, which may be of interest to integration and multi-functionality of electronic devices. PMID:25835175

Multi-susceptibile single-phased ceramics with both considerable magnetic and dielectric properties by selectively doping.

PubMed

Liu, Chuyang; Zhang, Yujing; Jia, Jingguo; Sui, Qiang; Ma, Ning; Du, Piyi

2015-04-02

Multiferroic ceramics with extraordinary susceptibilities coexisting are vitally important for the multi-functionality and integration of electronic devices. However, multiferroic composites, as the most potential candidates, will introduce inevitable interface deficiencies and thus dielectric loss from dissimilar phases. In this study, single-phased ferrite ceramics with considerable magnetic and dielectric performances appearing simultaneously were fabricated by doping target ions in higher valence than that of Fe(3+), such as Ti(4+), Nb(5+) and Zr(4+), into BaFe12O19. In terms of charge balance, Fe(3+)/Fe(2+) pair dipoles are produced through the substitution of Fe(3+) by high-valenced ions. The electron hopping between Fe(3+) and Fe(2+) ions results in colossal permittivity. Whilst the single-phased ceramics doped by target ions exhibit low dielectric loss naturally due to the diminishment of interfacial polarization and still maintain typical magnetic properties. This study provides a convenient method to attain practicable materials with both outstanding magnetic and dielectric properties, which may be of interest to integration and multi-functionality of electronic devices.

Multi-susceptibile Single-Phased Ceramics with Both Considerable Magnetic and Dielectric Properties by Selectively Doping

NASA Astrophysics Data System (ADS)

Liu, Chuyang; Zhang, Yujing; Jia, Jingguo; Sui, Qiang; Ma, Ning; Du, Piyi

2015-04-01

Multiferroic ceramics with extraordinary susceptibilities coexisting are vitally important for the multi-functionality and integration of electronic devices. However, multiferroic composites, as the most potential candidates, will introduce inevitable interface deficiencies and thus dielectric loss from dissimilar phases. In this study, single-phased ferrite ceramics with considerable magnetic and dielectric performances appearing simultaneously were fabricated by doping target ions in higher valence than that of Fe3+, such as Ti4+, Nb5+ and Zr4+, into BaFe12O19. In terms of charge balance, Fe3+/Fe2+ pair dipoles are produced through the substitution of Fe3+ by high-valenced ions. The electron hopping between Fe3+ and Fe2+ ions results in colossal permittivity. Whilst the single-phased ceramics doped by target ions exhibit low dielectric loss naturally due to the diminishment of interfacial polarization and still maintain typical magnetic properties. This study provides a convenient method to attain practicable materials with both outstanding magnetic and dielectric properties, which may be of interest to integration and multi-functionality of electronic devices.

Adaptable Single Active Loop Thermal Control System (TCS) for Future Space Missions

NASA Technical Reports Server (NTRS)

Mudawar, Issam; Lee, Seunghyun; Hasan, Mohammad

2015-01-01

This presentation will examine the development of a thermal control system (TCS) for future space missions utilizing a single active cooling loop. The system architecture enables the TCS to be reconfigured during the various mission phases to respond, not only to varying heat load, but to heat rejection temperature as well. The system will consist of an accumulator, pump, cold plates (evaporators), condenser radiator, and compressor, in addition to control, bypass and throttling valves. For cold environments, the heat will be rejected by radiation, during which the compressor will be bypassed, reducing the system to a simple pumped loop that, depending on heat load, can operate in either a single-phase liquid mode or two-phase mode. For warmer environments, the pump will be bypassed, enabling the TCS to operate as a heat pump. This presentation will focus on recent findings concerning two-phase flow regimes, pressure drop, and heat transfer coefficient trends in the cabin and avionics micro-channel heat exchangers when using the heat pump mode. Also discussed will be practical implications of using micro-channel evaporators for the heat pump.

Design of new face-centered cubic high entropy alloys by thermodynamic calculation

NASA Astrophysics Data System (ADS)

Choi, Won-Mi; Jung, Seungmun; Jo, Yong Hee; Lee, Sunghak; Lee, Byeong-Joo

2017-09-01

A new face-centered cubic (fcc) high entropy alloy system with non-equiatomic compositions has been designed by utilizing a CALculation of PHAse Diagram (CALPHAD) - type thermodynamic calculation technique. The new alloy system is based on the representative fcc high entropy alloy, the Cantor alloy which is an equiatomic Co- Cr-Fe-Mn-Ni five-component alloy, but fully or partly replace the cobalt by vanadium and is of non-equiatomic compositions. Alloy compositions expected to have an fcc single-phase structure between 700 °C and melting temperatures are proposed. All the proposed alloys are experimentally confirmed to have the fcc single-phase during materials processes (> 800 °C), through an X-ray diffraction analysis. It is shown that there are more chances to find fcc single-phase high entropy alloys if paying attention to non-equiatomic composition regions and that the CALPHAD thermodynamic calculation can be an efficient tool for it. An alloy design technique based on thermodynamic calculation is demonstrated and the applicability and limitation of the approach as a design tool for high entropy alloys is discussed.

An ensemble and single-molecule fluorescence microscopy investigation of phase-separated monolayer films stained with Nile Red.

PubMed

Lu, Yin; Porterfield, Robyn; Thunder, Terri; Paige, Matthew F

2011-01-01

Phase-separated Langmuir-Blodgett monolayer films prepared from mixtures of arachidic acid (C19H39COOH) and perfluorotetradecanoic acid (C13F27COOH) were stained via spin-casting with the polarity sensitive phenoxazine dye Nile Red, and characterized using a combination of ensemble and single-molecule fluorescence microscopy measurements. Ensemble fluorescence microscopy and spectromicroscopy showed that Nile Red preferentially associated with the hydrogenated domains of the phase-separated films, and was strongly fluorescent in these areas of the film. These measurements, in conjunction with single-molecule fluorescence imaging experiments, also indicated that a small sub-population of dye molecules localizes on the perfluorinated regions of the sample, but that this sub-population is spectroscopically indistinguishable from that associated with the hydrogenated domains. The relative importance of selective dye adsorption and local polarity sensitivity of Nile Red for staining applications in phase-separated LB films as well as in cellular environments is discussed in context of the experimental results. Copyright © 2010 Elsevier B.V. All rights reserved.

Communication: Two-dimensional gas-phase coherent anti-Stokes Raman spectroscopy (2D-CARS): Simultaneous planar imaging and multiplex spectroscopy in a single laser shot

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bohlin, Alexis; Kliewer, Christopher J.

2013-01-01

Coherent anti-Stokes Raman spectroscopy (CARS) has been widely used as a powerful tool for chemical sensing, molecular dynamics measurements, and rovibrational spectroscopy since its development over 30 years ago, finding use in fields of study as diverse as combustion diagnostics, cell biology, plasma physics, and the standoff detection of explosives. The capability for acquiring resolved CARS spectra in multiple spatial dimensions within a single laser shot has been a long-standing goal for the study of dynamical processes, but has proven elusive because of both phase-matching and detection considerations. Here, by combining new phase matching and detection schemes with the highmore » efficiency of femtosecond excitation of Raman coherences, we introduce a technique for single-shot two-dimensional (2D) spatial measurements of gas phase CARS spectra. We demonstrate a spectrometer enabling both 2D plane imaging and spectroscopy simultaneously, and present the instantaneous measurement of 15, 000 spatially correlated rotational CARS spectra in N 2 and air over a 2D field of 40 mm 2.« less

All-optical single-sideband frequency upconversion utilizing the XPM effect in an SOA-MZI.

PubMed

Kim, Doo-Ho; Lee, Joo-Young; Choi, Hyung-June; Song, Jong-In

2016-09-05

An all-optical single sideband (OSSB) frequency upconverter based on the cross-phase modulation (XPM) effect is proposed and experimentally demonstrated to overcome the power fading problem caused by the chromatic dispersion of fiber in radio-over-fiber systems. The OSSB frequency upconverter consists of an arrayed waveguide grating (AWG) and a semiconductor optical amplifier Mach-Zehnder interferometer (SOA-MZI) and does not require an extra delay line used for phase noise compensation. The generated OSSB radio frequency (RF) signal transmitted over single-mode fibers up to 20 km shows a flat electrical RF power response as a function of the fiber length. The upconverted electrical RF signal at 48 GHz shows negligible degradation of the phase noise even without an extra delay line. The measured phase noise of the upconverted RF signal (48 GHz) is -74.72 dBc/Hz at an offset frequency of 10 kHz. The spurious free dynamic range (SFDR) measured by a two-tone test to estimate the linearity of the OSSB frequency upconverter is 72.5 dB·Hz^2/3.

Conventional sample enrichment strategies combined with high-performance liquid chromatography-solid phase extraction-nuclear magnetic resonance analysis allows analyte identification from a single minuscule Corydalis solida plant tuber.

PubMed

Sturm, Sonja; Seger, Christoph; Godejohann, Markus; Spraul, Manfred; Stuppner, Hermann

2007-09-07

Identification of putative biomarker molecules within the genus Corydalis (Papaveraceae) was pursued by combining conventional off-line sample enrichment with high-performance liquid chromatography-solid phase extraction-nuclear magnetic resonance (HPLC-SPE-NMR) based structure elucidation. Off-line reversed phase solid phase extraction (SPE) was used to enrich the desired analytes from a methanolic extract (93 mg dry weight) of a miniscule single tuber (233 mg dry weight) of C. solida. An aliquot of the SPE fraction (2.1 mg) was subjected to separation in the HPLC-SPE-NMR hyphenation. Chromatographic peaks bearing the metabolites under investigation were trapped in the SPE device in a single experiment and transferred to a 600 MHz NMR spectrometer equipped with a 30 microl cryofit insert fed into a 3 mm cryoprobe. Recorded homo- and heteronuclear 1D and 2D NMR data allowed the identification of the three analytes under investigation as protopine, allocryptopine, and N-methyl-laudanidinium acetate. The latter is a rare alkaloid, which has been isolated only once before.

Microstructure and pinning properties of hexagonal-disc shaped single crystalline MgB2

NASA Astrophysics Data System (ADS)

Jung, C. U.; Kim, J. Y.; Chowdhury, P.; Kim, Kijoon H.; Lee, Sung-Ik; Koh, D. S.; Tamura, N.; Caldwell, W. A.; Patel, J. R.

2002-11-01

We synthesized hexagonal-disc-shaped MgB2 single crystals under high-pressure conditions and analyzed the microstructure and pinning properties. The lattice constants and the Laue pattern of the crystals from x-ray micro-diffraction showed the crystal symmetry of MgB2. A thorough crystallographic mapping within a single crystal showed that the edge and c axis of hexagonal-disc shape exactly matched the [101¯0] and the [0001] directions of the MgB2 phase. Thus, these well-shaped single crystals may be the best candidates for studying the direction dependences of the physical properties. The magnetization curve and the magnetic hysteresis curve for these single crystals showed the existence of a wide reversible region and weak pinning properties, which supported our single crystals being very clean.

Arrhenius Behavior of the Bulk Na-Ion Conductivity in Na3Sc2(PO4)3 Single Crystals Observed by Microcontact Impedance Spectroscopy.

PubMed

Rettenwander, Daniel; Redhammer, Günther J; Guin, Marie; Benisek, Artur; Krüger, Hannes; Guillon, Olivier; Wilkening, Martin; Tietz, Frank; Fleig, Jürgen

2018-03-13

NASICON-based solid electrolytes with exceptionally high Na-ion conductivities are considered to enable future all solid-state Na-ion battery technologies. Despite 40 years of research the interrelation between crystal structure and Na-ion conduction is still controversially discussed and far from being fully understood. In this study, microcontact impedance spectroscopy combined with single crystal X-ray diffraction, and differential scanning calorimetry is applied to tackle the question how bulk Na-ion conductivity σ bulk of sub-mm-sized flux grown Na 3 Sc 2 (PO 4 ) 3 (NSP) single crystals is influenced by supposed phase changes (α, β, and γ phase) discussed in literature. Although we found a smooth structural change at around 140 °C, which we assign to the β → γ phase transition, our conductivity data follow a single Arrhenius law from room temperature (RT) up to 220 °C. Obviously, the structural change, being mainly related to decreasing Na-ion ordering with increasing temperature, does not cause any jumps in Na-ion conductivity or any discontinuities in activation energies E a . Bulk ion dynamics in NSP have so far rarely been documented; here, under ambient conditions, σ bulk turned out to be as high as 3 × 10 -4 S cm -1  at RT ( E a, bulk = 0.39 eV) when directly measured with microcontacts for individual small single crystals.

Arrhenius Behavior of the Bulk Na-Ion Conductivity in Na3Sc2(PO4)3 Single Crystals Observed by Microcontact Impedance Spectroscopy

PubMed Central

2018-01-01

NASICON-based solid electrolytes with exceptionally high Na-ion conductivities are considered to enable future all solid-state Na-ion battery technologies. Despite 40 years of research the interrelation between crystal structure and Na-ion conduction is still controversially discussed and far from being fully understood. In this study, microcontact impedance spectroscopy combined with single crystal X-ray diffraction, and differential scanning calorimetry is applied to tackle the question how bulk Na-ion conductivity σbulk of sub-mm-sized flux grown Na3Sc2(PO4)3 (NSP) single crystals is influenced by supposed phase changes (α, β, and γ phase) discussed in literature. Although we found a smooth structural change at around 140 °C, which we assign to the β → γ phase transition, our conductivity data follow a single Arrhenius law from room temperature (RT) up to 220 °C. Obviously, the structural change, being mainly related to decreasing Na-ion ordering with increasing temperature, does not cause any jumps in Na-ion conductivity or any discontinuities in activation energies Ea. Bulk ion dynamics in NSP have so far rarely been documented; here, under ambient conditions, σbulk turned out to be as high as 3 × 10–4 S cm–1 at RT (Ea, bulk = 0.39 eV) when directly measured with microcontacts for individual small single crystals. PMID:29606799

A Two-length Scale Turbulence Model for Single-phase Multi-fluid Mixing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schwarzkopf, J. D.; Livescu, D.; Baltzer, J. R.

2015-09-08

A two-length scale, second moment turbulence model (Reynolds averaged Navier-Stokes, RANS) is proposed to capture a wide variety of single-phase flows, spanning from incompressible flows with single fluids and mixtures of different density fluids (variable density flows) to flows over shock waves. The two-length scale model was developed to address an inconsistency present in the single-length scale models, e.g. the inability to match both variable density homogeneous Rayleigh-Taylor turbulence and Rayleigh-Taylor induced turbulence, as well as the inability to match both homogeneous shear and free shear flows. The two-length scale model focuses on separating the decay and transport length scales,more » as the two physical processes are generally different in inhomogeneous turbulence. This allows reasonable comparisons with statistics and spreading rates over such a wide range of turbulent flows using a common set of model coefficients. The specific canonical flows considered for calibrating the model include homogeneous shear, single-phase incompressible shear driven turbulence, variable density homogeneous Rayleigh-Taylor turbulence, Rayleigh-Taylor induced turbulence, and shocked isotropic turbulence. The second moment model shows to compare reasonably well with direct numerical simulations (DNS), experiments, and theory in most cases. The model was then applied to variable density shear layer and shock tube data and shows to be in reasonable agreement with DNS and experiments. Additionally, the importance of using DNS to calibrate and assess RANS type turbulence models is highlighted.« less

Electro-optic routing of photons from a single quantum dot in photonic integrated circuits

NASA Astrophysics Data System (ADS)

Midolo, Leonardo; Hansen, Sofie L.; Zhang, Weili; Papon, Camille; Schott, Rüdiger; Ludwig, Arne; Wieck, Andreas D.; Lodahl, Peter; Stobbe, Søren

2017-12-01

Recent breakthroughs in solid-state photonic quantum technologies enable generating and detecting single photons with near-unity efficiency as required for a range of photonic quantum technologies. The lack of methods to simultaneously generate and control photons within the same chip, however, has formed a main obstacle to achieving efficient multi-qubit gates and to harness the advantages of chip-scale quantum photonics. Here we propose and demonstrate an integrated voltage-controlled phase shifter based on the electro-optic effect in suspended photonic waveguides with embedded quantum emitters. The phase control allows building a compact Mach-Zehnder interferometer with two orthogonal arms, taking advantage of the anisotropic electro-optic response in gallium arsenide. Photons emitted by single self-assembled quantum dots can be actively routed into the two outputs of the interferometer. These results, together with the observed sub-microsecond response time, constitute a significant step towards chip-scale single-photon-source de-multiplexing, fiber-loop boson sampling, and linear optical quantum computing.

Watching conformational- and photo-dynamics of single fluorescent proteins in solution.

PubMed

Goldsmith, Randall H; Moerner, W E

2010-03-01

Observing the dynamics of single biomolecules over prolonged time periods is difficult to achieve without significantly altering the molecule through immobilization. It can, however, be accomplished using the Anti-Brownian ELectrokinetic (ABEL) Trap, which allows extended investigation of solution-phase biomolecules - without immobilization -through real-time electrokinetic feedback. Here we apply the ABEL trap to study an important photosynthetic antenna protein, Allophycocyanin (APC). The technique allows the observation of single molecules of solution-phase APC for more than one second. We observe a complex relationship between fluorescence intensity and lifetime that cannot be explained by simple static kinetic models. Light-induced conformational changes are shown to occur and evidence is obtained for fluctuations in the spontaneous emission lifetime, which is typically assumed to be constant. Our methods provide a new window into the dynamics of fluorescent proteins and the observations are relevant for the interpretation of in vivo single-molecule imaging experiments, bacterial photosynthetic regulation, and biomaterials for solar energy harvesting.

Time-dependent behavior in a transport-barrier model for the quasi-single helcity state

NASA Astrophysics Data System (ADS)

Terry, P. W.; Whelan, G. G.

2014-09-01

Time-dependent behavior that follows from a recent theory of the quasi-single-helicity (QSH) state of the reversed field pinch is considered. The theory (Kim and Terry 2012 Phys. Plasmas 19 122304) treats QSH as a core fluctuation structure tied to a tearing mode of the same helicity, and shows that strong magnetic and velocity shears in the structure suppress the nonlinear interaction with other fluctuations. By summing the multiple helicity fluctuation energies over wavenumber, we reduce the theory to a predator-prey model. The suppression of the nonlinear interaction is governed by the single helicity energy, which, for fixed radial structure, controls the magnetic and velocity shearing rates. It is also controlled by plasma current which, in the theory, sets the shearing threshold for suppression. The model shows a limit cycle oscillation in which the system toggles between QSH and multiple helicity states, with the single helicity phase becoming increasingly long-lived relative to the multiple helicity phase as plasma current increases.

Amount of fear extinction changes its underlying mechanisms

PubMed Central

An, Bobae; Kim, Jihye; Park, Kyungjoon; Lee, Sukwon; Song, Sukwoon; Choi, Sukwoo

2017-01-01

There has been a longstanding debate on whether original fear memory is inhibited or erased after extinction. One possibility that reconciles this uncertainty is that the inhibition and erasure mechanisms are engaged in different phases (early or late) of extinction. In this study, using single-session extinction training and its repetition (multiple-session extinction training), we investigated the inhibition and erasure mechanisms in the prefrontal cortex and amygdala of rats, where neural circuits underlying extinction reside. The inhibition mechanism was prevalent with single-session extinction training but faded when single-session extinction training was repeated. In contrast, the erasure mechanism became prevalent when single-session extinction training was repeated. Moreover, ablating the intercalated neurons of amygdala, which are responsible for maintaining extinction-induced inhibition, was no longer effective in multiple-session extinction training. We propose that the inhibition mechanism operates primarily in the early phase of extinction training, and the erasure mechanism takes over after that. DOI: http://dx.doi.org/10.7554/eLife.25224.001 PMID:28671550

Interior radiances in optically deep absorbing media. III Scattering from Haze L

NASA Technical Reports Server (NTRS)

Kattawar, G. W.; Plass, G. N.

1975-01-01

The interior radiances are calculated within an optically deep absorbing medium scattering according to the Haze L phase function. The dependence on the solar zenith angle, the single scattering albedo, and the optical depth within the medium is calculated by the matrix operator method. The development of the asymptotic angular distribution of the radiance in the diffusion region is illustrated through a number of examples; it depends only on the single scattering albedo and on the phase function for single scattering. The exact values of the radiance in the diffusion region are compared with values calculated from the approximate equations proposed by Van de Hulst. The variation of the radiance near the lower boundary of an optically thick medium is illustrated with examples. The attenuation length is calculated for various single scattering albedos and compared with the corresponding values for Rayleigh scattering. The ratio of the upward to the downward flux is found to be remarkably constant within the medium.

The effect of single-horn glaze ice on the vortex structures in the wake of a horizontal axis wind turbine

NASA Astrophysics Data System (ADS)

Jin, Zhe-Yan; Dong, Qiao-Tian; Yang, Zhi-Gang

2015-02-01

The present study experimentally investigated the effect of a simulated single-horn glaze ice accreted on rotor blades on the vortex structures in the wake of a horizontal axis wind turbine by using the stereoscopic particle image velocimetry (Stereo-PIV) technique. During the experiments, four horizontal axis wind turbine models were tested, and both "free-run" and "phase-locked" Stereo-PIV measurements were carried out. Based on the "free-run" measurements, it was found that because of the simulated single-horn glaze ice, the shape, vorticity, and trajectory of tip vortices were changed significantly, and less kinetic energy of the airflow could be harvested by the wind turbine. In addition, the "phase-locked" results indicated that the presence of simulated single-horn glaze ice resulted in a dramatic reduction of the vorticity peak of the tip vortices. Moreover, as the length of the glaze ice increased, both root and tip vortex gaps were found to increase accordingly.

Watching conformational- and photo-dynamics of single fluorescent proteins in solution

PubMed Central

Goldsmith, Randall H.

2010-01-01

Observing the dynamics of single biomolecules over prolonged time periods is difficult to achieve without significantly altering the molecule through immobilization. It can, however, be accomplished using the Anti-Brownian ELectrokinetic (ABEL) Trap, which allows extended investigation of solution-phase biomolecules - without immobilization -through real-time electrokinetic feedback. Here we apply the ABEL trap to study an important photosynthetic antenna protein, Allophycocyanin (APC). The technique allows the observation of single molecules of solution-phase APC for more than one second. We observe a complex relationship between fluorescence intensity and lifetime that cannot be explained by simple static kinetic models. Light-induced conformational changes are shown to occur and evidence is obtained for fluctuations in the spontaneous emission lifetime, which is typically assumed to be constant. Our methods provide a new window into the dynamics of fluorescent proteins and the observations are relevant for the interpretation of in vivo single-molecule imaging experiments, bacterial photosynthetic regulation, and biomaterials for solar energy harvesting. PMID:20625479

Watching conformational- and photodynamics of single fluorescent proteins in solution

NASA Astrophysics Data System (ADS)

Goldsmith, Randall H.; Moerner, W. E.

2010-03-01

Observing the dynamics of single biomolecules over prolonged time periods is difficult to achieve without significantly altering the molecule through immobilization. It can, however, be accomplished using the anti-Brownian electrokinetic trap, which allows extended investigation of solution-phase biomolecules-without immobilization-through real-time electrokinetic feedback. Here we apply the trap to study an important photosynthetic antenna protein, allophycocyanin. The technique allows the observation of single molecules of solution-phase allophycocyanin for more than one second. We observe a complex relationship between fluorescence intensity and lifetime that cannot be explained by simple static kinetic models. Light-induced conformational changes are shown to occur and evidence is obtained for fluctuations in the spontaneous emission lifetime, which is typically assumed to be constant. Our methods provide a new window into the dynamics of fluorescent proteins and the observations are relevant for the interpretation of in vivo single-molecule imaging experiments, bacterial photosynthetic regulation and biomaterials for solar energy harvesting.

Reversible adapting layer produces robust single-crystal electrocatalyst for oxygen evolution.

PubMed

Tung, Ching-Wei; Hsu, Ying-Ya; Shen, Yen-Ping; Zheng, Yixin; Chan, Ting-Shan; Sheu, Hwo-Shuenn; Cheng, Yuan-Chung; Chen, Hao Ming

2015-08-28

Electrochemically converting water into oxygen/hydrogen gas is ideal for high-density renewable energy storage in which robust electrocatalysts for efficient oxygen evolution play crucial roles. To date, however, electrocatalysts with long-term stability have remained elusive. Here we report that single-crystal Co3O4 nanocube underlay with a thin CoO layer results in a high-performance and high-stability electrocatalyst in oxygen evolution reaction. An in situ X-ray diffraction method is developed to observe a strong correlation between the initialization of the oxygen evolution and the formation of active metal oxyhydroxide phase. The lattice of skin layer adapts to the structure of the active phase, which enables a reversible facile structural change that facilitates the chemical reactions without breaking the scaffold of the electrocatalysts. The single-crystal nanocube electrode exhibits stable, continuous oxygen evolution for >1,000 h. This robust stability is attributed to the complementary nature of defect-free single-crystal electrocatalyst and the reversible adapting layer.

Strong anisotropy and magnetostriction in the two-dimensional Stoner ferromagnet Fe 3 GeTe 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhuang, Houlong L.; Kent, P. R. C.; Hennig, Richard G.

Comore » mputationally characterizing magnetic properies of novel two-dimensional (2D) materials serves as an important first step of exploring possible applications. Using density-functional theory, we show that single-layer Fe 3 GeTe 2 is a potential 2D material with sufficiently low formation energy to be synthesized by mechanical exfoliation from the bulk phase with a van der Waals layered structure. In addition, we calculated the phonon dispersion demonstrating that single-layer Fe 3 GeTe 2 is dynamically stable. Furthermore, we find that similar to the bulk phase, 2D Fe 3 GeTe 2 exhibits amagnetic moment that originates from a Stoner instability. In contrast to other 2D materials, we find that single-layer Fe 3 GeTe 2 exhibits a significant uniaxial magnetocrystalline anisotropy energy of 920μ eV per Fe atom originating from spin-orbit coupling. In conclusion, we show that applying biaxial tensile strains enhances the anisotropy energy, which reveals strong magnetostriction in single-layer Fe 3 GeTe 2 with a sizable magneostrictive coefficient. Our results indicate that single-layer Fe 3 GeTe 2 is potentially useful for magnetic storage applications.« less

Strong anisotropy and magnetostriction in the two-dimensional Stoner ferromagnet Fe 3 GeTe 2

DOE PAGES

Zhuang, Houlong L.; Kent, P. R. C.; Hennig, Richard G.

2016-04-06

Comore » mputationally characterizing magnetic properies of novel two-dimensional (2D) materials serves as an important first step of exploring possible applications. Using density-functional theory, we show that single-layer Fe 3 GeTe 2 is a potential 2D material with sufficiently low formation energy to be synthesized by mechanical exfoliation from the bulk phase with a van der Waals layered structure. In addition, we calculated the phonon dispersion demonstrating that single-layer Fe 3 GeTe 2 is dynamically stable. Furthermore, we find that similar to the bulk phase, 2D Fe 3 GeTe 2 exhibits amagnetic moment that originates from a Stoner instability. In contrast to other 2D materials, we find that single-layer Fe 3 GeTe 2 exhibits a significant uniaxial magnetocrystalline anisotropy energy of 920μ eV per Fe atom originating from spin-orbit coupling. In conclusion, we show that applying biaxial tensile strains enhances the anisotropy energy, which reveals strong magnetostriction in single-layer Fe 3 GeTe 2 with a sizable magneostrictive coefficient. Our results indicate that single-layer Fe 3 GeTe 2 is potentially useful for magnetic storage applications.« less

Dependences of the density of M 1- x R x F2 + x and R 1- y M y F3- y single crystals ( M = Ca, Sr, Ba, Cd, Pb; R means rare earth elements) on composition

NASA Astrophysics Data System (ADS)

Sorokin, N. I.; Krivandina, E. A.; Zhmurova, Z. I.

2013-11-01

The density of single crystals of nonstoichiometric phases Ba1 - x La x F2 + x (0 ≤ x ≤ 0.5) and Sr0.8La0.2 - x Lu x F2.2 (0 ≤ x ≤ 0.2) with the fluorite (CaF2) structure type and R 1 - y Sr y F3 - y ( R = Pr, Nd; 0 ≤ y ≤ 0.15) with the tysonite (LaF3) structure type has been measured. Single crystals were grown from a melt by the Bridgman method. The measured concentration dependences of single crystal density are linear. The interstitial and vacancy models of defect formation in the fluorite and tysonite phases, respectively, are confirmed. To implement the composition control of single crystals of superionic conductors M 1 - x R x F2 + x and R 1 - y M y F3 - y in practice, calibration graphs of X-ray density in the MF2- RF3 systems ( M = Ca, Sr, Ba, Cd, Pb; R = La-Lu, Y) are plotted.

Formation mechanism of superconducting phase and its three-dimensional architecture in pseudo-single-crystal K xFe 2-ySe 2

DOE PAGES

Liu, Yong; Xing, Qingfeng; Straszheim, Warren E.; ...

2016-02-11

Here, we report how the superconducting phase forms in pseudo-single-crystal K xFe 2-ySe 2. In situ scanning electron microscopy (SEM) observation reveals that, as an order-disorder transition occurs, on cooling, most of the high-temperature iron-vacancy-disordered phase gradually changes into the iron-vacancy-ordered phase whereas a small quantity of the high-temperature phase retains its structure and aggregates to the stripes with more iron concentration but less potassium concentration compared to the iron-vacancy-ordered phase. The stripes that are generally recognized as the superconducting phase are actually formed as a remnant of the high-temperature phase with a compositional change after an “imperfect” order-disorder transition.more » It should be emphasized that the phase separation in pseudo-single-crystal K xFe 2-ySe 2 is caused by the iron-vacancy order-disorder transition. The shrinkage of the high-temperature phase and the expansion of the newly created iron-vacancy-ordered phase during the phase separation rule out the mechanism of spinodal decomposition proposed in an early report [Wang et al, Phys. Rev. B 91, 064513 (2015)]. Since the formation of the superconducting phase relies on the occurrence of the iron-vacancy order-disorder transition, it is impossible to synthesize a pure superconducting phase by a conventional solid state reaction or melt growth. By focused ion beam-scanning electron microscopy, we further demonstrate that the superconducting phase forms a contiguous three-dimensional architecture composed of parallelepipeds that have a coherent orientation relationship with the iron-vacancy-ordered phase.« less

Spatial Factors in the Integration of Speed Information

NASA Technical Reports Server (NTRS)

Verghese, P.; Stone, L. S.; Hargens, Alan R. (Technical Monitor)

1995-01-01

We reported that, for a 21FC task with multiple Gabor patches in each interval, thresholds for speed discrimination decreased with the number of patches, while simply increasing the area of a single patch produced no such effect. This result could be explained by multiple patches reducing spatial uncertainty. However, the fact that thresholds decrease with number even when the patches are in fixed positions argues against this explanation. We therefore performed additional experiments to explore the lack of an area effect. Three observers did a 21FC speed discrimination task with 6 Gabor patches in each interval, and were asked to pick the interval in which the gratings moved faster. The 50% contrast patches were placed on a circle at 4 deg. eccentricity, either equally spaced and maximally separated (hexagonal array), or closely-spaced, in consecutive positions (string of pearls). For the string-of-pearls condition, the grating phases were either random, or consistent with a full-field grating viewed through multiple Gaussian windows. When grating phases were random, the thresholds for the hexagonal and string-of-pearls layouts were indistinguishable. For the string-of-pearls layout, thresholds in the consistent-phase condition were higher by 15 +/- 6% than in the random-phase condition. (Thresholds increased by 57 +/- 7% in going from 6 patches to a single patch of equivalent area.). For random-phase patches, the lower thresholds for 6 patches does not depend on a specific spacing or spatial layout. Multiple, closely-spaced, consistent-phase patches that can be interpreted as a single grating, result in thresholds closer to that produced by a single patch. Together, our results suggest that object segmentation may play a role in the integration of speed information.

Unraveling the Complex Delithiation Mechanisms of Olivine-Type Cathode Materials, LiFe x Co 1–x PO 4

DOE Office of Scientific and Technical Information (OSTI.GOV)

Strobridge, Fiona C.; Liu, Hao; Leskes, Michal

2016-06-14

The delithiation mechanisms occurring within the olivine-type class of cathode materials for Li-ion batteries have received considerable attention owing to the good capacity retention at high rates for LiFePO4. A comprehensive mechanistic study of the (de)lithiation reactions that occur when the substituted olivine-type cathode materials LiFexCo1-xPO4 (x = 0, 0.05, 0.125, 0.25, 0.5, 0.75, 0.875, 0.95 and 1) are electrochemically cycled is reported here, using in situ X-ray diffraction (XRD) data. On the first charge, two intermediate phases are observed and identified: Li1-x(Fe3+)x(Co2+)1- xPO4 for 0 < x < 1 (i.e. after oxidation of Fe2+ => Fe3+) and Li2/3FexCo1-xPO4 formore » 0 ≤ x ≤ 0.5 (i.e. the Co-majority materials). For the Fe-rich materials, we study how nonequilibrium, single-phase mechanisms that occur discretely in single particles, as observed for LiFePO4 at high rates, is affected by Co substitution. In the Co-majority materials, a two-phase mechanism with a coherent interface is observed, as was seen in LiCoPO4, and we discuss how it is manifested in the XRD patterns. We then compare the nonequilibrium, single-phase mechanism with the bulk single-phase and the coherent interface two-phase mechanisms. Despite the apparent differences between these mechanisms, we discuss how they are related and interconverted as a function of Fe/Co substitution and the potential implications for the electrochemistry of this system.« less

Structure and electrical properties of intergrowth bismuth layer-structured Bi4Ti3O12-CaBi4Ti4O15 ferroelectric ceramics

NASA Astrophysics Data System (ADS)

Choi, Gi Ppeum; Cho, Sam Yeon; Bu, Sang Don

2016-09-01

Pb-free ferroelectric Bi4Ti3O12-CaBi4Ti4O15 (BIT-CBT) ceramics were manufactured using a solid-state reaction method. Structural analysis by using X-ray diffraction confirmed the presence of a second phase of Bi2Ti2O7, and the surface depth X-ray diffraction analysis revealed that this phase existed only on the surface. This second phase appears to have been caused by the volatilization of Bi ions at high sintering temperatures. For resolution of the issue of volatilization of Bi ions and manufacture of BIT-CBT ceramics with a single phase, Bi2O3 powder was added to the BIT-CBT mixture, and a powder-bed method, in which pellets were covered with BIT-CBT powder, was used to manufacture the ceramic. The piezoelectric coefficient of the single-phase BIT-CBT ceramics was 12.4 pC/N while the residual polarization and the coercive electric field were 11.3 μC/cm2, and 125 kV/cm, respectively. The results suggest that single-phase BIT-CBT ceramics are suitable for the manufacture of elements incorporating these electrical characteristics.

Single grating x-ray imaging for dynamic biological systems

NASA Astrophysics Data System (ADS)

Morgan, Kaye S.; Paganin, David M.; Parsons, David W.; Donnelley, Martin; Yagi, Naoto; Uesugi, Kentaro; Suzuki, Yoshio; Takeuchi, Akihisa; Siu, Karen K. W.

2012-07-01

Biomedical studies are already benefiting from the excellent contrast offered by phase contrast x-ray imaging, but live imaging work presents several challenges. Living samples make it particularly difficult to achieve high resolution, sensitive phase contrast images, as exposures must be short and cannot be repeated. We therefore present a single-exposure, high-flux method of differential phase contrast imaging [1, 2, 3] in the context of imaging live airways for Cystic Fibrosis (CF) treatment assessment [4]. The CF study seeks to non-invasively observe the liquid lining the airways, which should increase in depth in response to effective treatments. Both high spatial resolution and sensitivity are required in order to track micron size changes in a liquid that is not easily differentiated from the tissue on which it lies. Our imaging method achieves these goals by using a single attenuation grating or grid as a reference pattern, and analyzing how the sample deforms the pattern to quantitatively retrieve the phase depth of the sample. The deformations are mapped at each pixel in the image using local cross-correlations comparing each 'sample and pattern' image with a reference 'pattern only' image taken before the sample is introduced. This produces a differential phase image, which may be integrated to give the sample phase depth.

SU-C-9A-06: The Impact of CT Image Used for Attenuation Correction in 4D-PET

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cui, Y; Bowsher, J; Yan, S

2014-06-01

Purpose: To evaluate the appropriateness of using 3D non-gated CT image for attenuation correction (AC) in a 4D-PET (gated PET) imaging protocol used in radiotherapy treatment planning simulation. Methods: The 4D-PET imaging protocol in a Siemens PET/CT simulator (Biograph mCT, Siemens Medical Solutions, Hoffman Estates, IL) was evaluated. CIRS Dynamic Thorax Phantom (CIRS Inc., Norfolk, VA) with a moving glass sphere (8 mL) in the middle of its thorax portion was used in the experiments. The glass was filled with {sup 18}F-FDG and was in a longitudinal motion derived from a real patient breathing pattern. Varian RPM system (Varian Medicalmore » Systems, Palo Alto, CA) was used for respiratory gating. Both phase-gating and amplitude-gating methods were tested. The clinical imaging protocol was modified to use three different CT images for AC in 4D-PET reconstruction: first is to use a single-phase CT image to mimic actual clinical protocol (single-CT-PET); second is to use the average intensity projection CT (AveIP-CT) derived from 4D-CT scanning (AveIP-CT-PET); third is to use 4D-CT image to do the phase-matched AC (phase-matching- PET). Maximum SUV (SUVmax) and volume of the moving target (glass sphere) with threshold of 40% SUVmax were calculated for comparison between 4D-PET images derived with different AC methods. Results: The SUVmax varied 7.3%±6.9% over the breathing cycle in single-CT-PET, compared to 2.5%±2.8% in AveIP-CT-PET and 1.3%±1.2% in phasematching PET. The SUVmax in single-CT-PET differed by up to 15% from those in phase-matching-PET. The target volumes measured from single- CT-PET images also presented variations up to 10% among different phases of 4D PET in both phase-gating and amplitude-gating experiments. Conclusion: Attenuation correction using non-gated CT in 4D-PET imaging is not optimal process for quantitative analysis. Clinical 4D-PET imaging protocols should consider phase-matched 4D-CT image if available to achieve better accuracy.« less

Extending Single-Molecule Microscopy Using Optical Fourier Processing

PubMed Central

2015-01-01

This article surveys the recent application of optical Fourier processing to the long-established but still expanding field of single-molecule imaging and microscopy. A variety of single-molecule studies can benefit from the additional image information that can be obtained by modulating the Fourier, or pupil, plane of a widefield microscope. After briefly reviewing several current applications, we present a comprehensive and computationally efficient theoretical model for simulating single-molecule fluorescence as it propagates through an imaging system. Furthermore, we describe how phase/amplitude-modulating optics inserted in the imaging pathway may be modeled, especially at the Fourier plane. Finally, we discuss selected recent applications of Fourier processing methods to measure the orientation, depth, and rotational mobility of single fluorescent molecules. PMID:24745862

Extending single-molecule microscopy using optical Fourier processing.

PubMed

Backer, Adam S; Moerner, W E

2014-07-17

This article surveys the recent application of optical Fourier processing to the long-established but still expanding field of single-molecule imaging and microscopy. A variety of single-molecule studies can benefit from the additional image information that can be obtained by modulating the Fourier, or pupil, plane of a widefield microscope. After briefly reviewing several current applications, we present a comprehensive and computationally efficient theoretical model for simulating single-molecule fluorescence as it propagates through an imaging system. Furthermore, we describe how phase/amplitude-modulating optics inserted in the imaging pathway may be modeled, especially at the Fourier plane. Finally, we discuss selected recent applications of Fourier processing methods to measure the orientation, depth, and rotational mobility of single fluorescent molecules.

Entanglement and quantum superposition induced by a single photon

NASA Astrophysics Data System (ADS)

Lü, Xin-You; Zhu, Gui-Lei; Zheng, Li-Li; Wu, Ying

2018-03-01

We predict the occurrence of single-photon-induced entanglement and quantum superposition in a hybrid quantum model, introducing an optomechanical coupling into the Rabi model. Originally, it comes from the photon-dependent quantum property of the ground state featured by the proposed hybrid model. It is associated with a single-photon-induced quantum phase transition, and is immune to the A2 term of the spin-field interaction. Moreover, the obtained quantum superposition state is actually a squeezed cat state, which can significantly enhance precision in quantum metrology. This work offers an approach to manipulate entanglement and quantum superposition with a single photon, which might have potential applications in the engineering of new single-photon quantum devices, and also fundamentally broaden the regime of cavity QED.

Stability characteristics of a single-phase free convection loop

NASA Technical Reports Server (NTRS)

Creveling, H. F.; De Paz, J. F.; Baladi, J. Y.; Schoenhals, R. J.

1975-01-01

Experiments investigating the stability characteristics of a single-phase free convection loop are reported. Results of the study confirm the contention made by previous workers that instabilities near the thermodynamic critical point can occur for ordinary fluids as well as those with unusual behavior in the near-critical region. Such a claim runs counter to traditional beliefs, but it is supported by the observation of such instabilities for water at atmospheric pressure and moderate temperatures in the present work.

Special Features of the Structure of Single-Crystal Refractory Nickel Alloy Under Directed Crystallization

NASA Astrophysics Data System (ADS)

Bondarenko, Yu. A.; Echin, A. B.; Surova, V. A.; Kolodyazhnyi, M. Yu.

2017-05-01

The effect of the conditions of directed crystallization (the temperature gradient and the crystallization rate) on the dendrite spacing, on the size of the particles of the hardening γ'-phase in the arms and arm spaces of the dendrites, on the volume fraction and size of the pores, on the size of the particles of the eutectic γ/γ'-phase, and on the features of dendritic segregation in a single-crystal castable refractory alloy is studied.

Triton's surface properties - A preliminary analysis from ground-based, Voyager photopolarimeter subsystem, and laboratory measurements

NASA Technical Reports Server (NTRS)

Buratti, B. J.; Lane, A. L.; Gibson, J.; Burrows, H.; Nelson, R. M.; Bliss, D.; Smythe, W.; Garkanian, V.; Wallis, B.

1991-01-01

The surface properties of Triton were investigated using data from the ground-based and Voyager photopolarimeter subsystem (PPS) observations of Triton's phase curve. The results indicate that Triton has a high single-scattering albedo (0.96 +/-0.01 at 0.75 micron) and an unusually compacted surface, possibly similar to that of Europa. Results also suggest that Triton's single-particle phase function and the macroscopically rough character of its surface are similar to those of most other icy satellites.

Core Length and Spray Width Measurements in Shear Coaxial Rocket Injectors from X-ray Radiography Measurements

DTIC Science & Technology

2015-05-01

liquid jet core; elliptical EPL is what would be expected from a cylinder of liquid and has previously been observed in diesel injector studies [22...and liquid rocket engines) shear coaxial jets have been stud- ied for over sixty years and have become a canonical problem for the study of rocket...research has been done using a single phase (either gas-gas or liquid - liquid mixing). A brief review of single-phase coaxial jet research can be

An empirical relationship for homogenization in single-phase binary alloy systems

NASA Technical Reports Server (NTRS)

Unnam, J.; Tenney, D. R.; Stein, B. A.

1979-01-01

A semiempirical formula is developed for describing the extent of interaction between constituents in single-phase binary alloy systems with planar, cylindrical, or spherical interfaces. The formula contains two parameters that are functions of mean concentration and interface geometry of the couple. The empirical solution is simple, easy to use, and does not involve sequential calculations, thereby allowing quick estimation of the extent of interactions without lengthy calculations. Results obtained with this formula are in good agreement with those from a finite-difference analysis.

Experimental circular quantum secret sharing over telecom fiber network.

PubMed

Wei, Ke-Jin; Ma, Hai-Qiang; Yang, Jian-Hui

2013-07-15

We present a robust single photon circular quantum secret sharing (QSS) scheme with phase encoding over 50 km single mode fiber network using a circular QSS protocol. Our scheme can automatically provide a perfect compensation of birefringence and remain stable for a long time. A high visibility of 99.3% is obtained. Furthermore, our scheme realizes a polarization insensitive phase modulators. The visibility of this system can be maintained perpetually without any adjustment to the system every time we test the system.

Single-shot measurement of ultrafast time-varying phase modulation induced by femtosecond laser pulses with arbitrary polarization

NASA Astrophysics Data System (ADS)

Hartinger, Klaus; Bartels, Randy A.

2008-01-01

We demonstrate a single-shot measurement of the transient phase modulation due to field free molecular alignment at the revival times of a rotational wave packet. The wave packet is excited by an arbitrarily polarized ultrashort laser pulse in CO2 at room temperature. With this technique the time dependence along the eigenpolarization directions of the linear susceptibility tensor, i.e., the time dependence of its principle components, can be directly observed with high sensitivity.

Nanomedicine photoluminescence crystal-inspired brain sensing approach

NASA Astrophysics Data System (ADS)

Fang, Yan; Wang, Fangzhen; Wu, Rong

2018-02-01

Precision sensing needs to overcome a gap of a single atomic step height standard. In response to the cutting-edge challenge, a heterosingle molecular nanomedicine crystal was developed wherein a nanomedicine crystal height less than 1 nm was designed and selfassembled on a substrate of either a highly ordered and freshly separated graphite or a N-doped silicon with hydrogen bonding by a home-made hybrid system of interacting single bioelectron donor-acceptor and a single biophoton donor-acceptor according to orthogonal mathematical optimization scheme, and an atomic spatial resolution conducting atomic force microscopy (C-AFM) with MHz signal processing by a special transformation of an atomic force microscopy (AFM) and a scanning tunneling microscopy (STM) were employed, wherein a z axis direction UV-VIS laser interferometer and a feedback circuit were used to achieve the minimized uncertainty of a micro-regional structure height and its corresponding local differential conductance quantization (spin state) process was repeatedly measured with a highly time resolution, as well as a pulsed UV-VIS laser micro-photoluminescence (PL) spectrum with a single photon resolution was set up by traceable quantum sensing and metrology relied up a quantum electrical triangle principle. The coupling of a single bioelectron conducting, a single biophoton photoluminescence, a frequency domain temporal spin phase in nanomedicine crystal-inspired sensing methods and sensor technologies were revealed by a combination of C-AFM and PL measurement data-based mathematic analyses1-3, as depicted in Figure 1 and repeated in nanomedicine crystals with a single atomic height. It is concluded that height-current-phase uncertainty correlation pave a way to develop a brain imaging and a single atomic height standard, quantum sensing, national security, worldwide impact1-3 technology and beyond.

Beyond Atomic Sizes and Hume-Rothery Rules: Understanding and Predicting High-Entropy Alloys

DOE PAGES

Troparevsky, M. Claudia; Morris, James R.; Daene, Markus; ...

2015-09-03

High-entropy alloys constitute a new class of materials that provide an excellent combination of strength, ductility, thermal stability, and oxidation resistance. Although they have attracted extensive attention due to their potential applications, little is known about why these compounds are stable or how to predict which combination of elements will form a single phase. Here, we present a review of the latest research done on these alloys focusing on the theoretical models devised during the last decade. We discuss semiempirical methods based on the Hume-Rothery rules and stability criteria based on enthalpies of mixing and size mismatch. To provide insightsmore » into the electronic and magnetic properties of high-entropy alloys, we show the results of first-principles calculations of the electronic structure of the disordered solid-solution phase based on both Korringa Kohn Rostoker coherent potential approximation and large supercell models of example face-centered cubic and body-centered cubic systems. Furthermore, we discuss in detail a model based on enthalpy considerations that can predict which elemental combinations are most likely to form a single-phase high-entropy alloy. The enthalpies are evaluated via first-principles high-throughput density functional theory calculations of the energies of formation of binary compounds, and therefore it requires no experimental or empirically derived input. Finally, the model correctly accounts for the specific combinations of metallic elements that are known to form single-phase alloys while rejecting similar combinations that have been tried and shown not to be single phase.« less

Giant Magnetoelectric Energy Conversion Utilizing Inter-Ferroelectric Phase Transformations in Ferroics

NASA Astrophysics Data System (ADS)

Finkel, Peter; Staruch, Margo

Phase transition-based electromechanical transduction permits achieving a non-resonant broadband mechanical energy conversion see (Finkel et al Actuators, 5 [1] 2. (2015)) , the idea is based on generation high energy density per cycle , at least 100x of magnitude larger than linear piezoelectric type generators in stress biased [011]cut relaxor ferroelectric Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) single crystal can generate reversible strain >0.35% at remarkably low fields (0.1 MV/m) for tens of millions of cycles. Recently we demonstrated that large strain and polarization rotation can be generated for over 40 x 106cycles with little fatigue by realization of reversible ferroelectric-ferroelectric phase transition in [011] cut PIN-PMN-PT relaxor ferroelectric single crystal while sweeping through the transition with a low applied electric field <0.18 MV/m under mechanical stress. This methodology was extended in the present work to propose magnetoelectric (ME) composite hybrid system comprised of highly magnetostrictive alloymFe81.4Ga18.6 (Galfenol), and lead indium niobate-lead magnesium niobate-lead titanate (PIN-PMN-PT) domain engineered relaxor ferroelectric single crystal. A small time-varying magnetic field applied to this system causes the magnetostrictive element to expand, and the resulting stress forces the phase change in the relaxor ferroelectric single crystal. ME coupling coefficient was fond to achieve 80 V/cm Oe near the FR-FO phase transition that is at least 100X of magnitude higher than any currently reported values.

Communication: phase transitions, criticality, and three-phase coexistence in constrained cell models.

PubMed

Nayhouse, Michael; Kwon, Joseph Sang-Il; Orkoulas, G

2012-05-28

In simulation studies of fluid-solid transitions, the solid phase is usually modeled as a constrained system in which each particle is confined to move in a single Wigner-Seitz cell. The constrained cell model has been used in the determination of fluid-solid coexistence via thermodynamic integration and other techniques. In the present work, the phase diagram of such a constrained system of Lennard-Jones particles is determined from constant-pressure simulations. The pressure-density isotherms exhibit inflection points which are interpreted as the mechanical stability limit of the solid phase. The phase diagram of the constrained system contains a critical and a triple point. The temperature and pressure at the critical and the triple point are both higher than those of the unconstrained system due to the reduction in the entropy caused by the single occupancy constraint.

Cooperative photoinduced metastable phase control in strained manganite films

NASA Astrophysics Data System (ADS)

Zhang, Jingdi; Tan, Xuelian; Liu, Mengkun; Teitelbaum, S. W.; Post, K. W.; Jin, Feng; Nelson, K. A.; Basov, D. N.; Wu, Wenbin; Averitt, R. D.

2016-09-01

A major challenge in condensed-matter physics is active control of quantum phases. Dynamic control with pulsed electromagnetic fields can overcome energetic barriers, enabling access to transient or metastable states that are not thermally accessible. Here we demonstrate strain-engineered tuning of La2/3Ca1/3MnO3 into an emergent charge-ordered insulating phase with extreme photo-susceptibility, where even a single optical pulse can initiate a transition to a long-lived metastable hidden metallic phase. Comprehensive single-shot pulsed excitation measurements demonstrate that the transition is cooperative and ultrafast, requiring a critical absorbed photon density to activate local charge excitations that mediate magnetic-lattice coupling that, in turn, stabilize the metallic phase. These results reveal that strain engineering can tune emergent functionality towards proximal macroscopic states to enable dynamic ultrafast optical phase switching and control.

Methods for forming particles

DOEpatents

Fox, Robert V.; Zhang, Fengyan; Rodriguez, Rene G.; Pak, Joshua J.; Sun, Chivin

2016-06-21

Single source precursors or pre-copolymers of single source precursors are subjected to microwave radiation to form particles of a I-III-VI.sub.2 material. Such particles may be formed in a wurtzite phase and may be converted to a chalcopyrite phase by, for example, exposure to heat. The particles in the wurtzite phase may have a substantially hexagonal shape that enables stacking into ordered layers. The particles in the wurtzite phase may be mixed with particles in the chalcopyrite phase (i.e., chalcopyrite nanoparticles) that may fill voids within the ordered layers of the particles in the wurtzite phase thus produce films with good coverage. In some embodiments, the methods are used to form layers of semiconductor materials comprising a I-III-VI.sub.2 material. Devices such as, for example, thin-film solar cells may be fabricated using such methods.

An investigation into the flow behavior of a single phase gas system and a two phase gas/liquid system in normal gravity with nonuniform heating from above

NASA Technical Reports Server (NTRS)

Disimile, Peter J.; Heist, Timothy J.

1990-01-01

The fluid behavior in normal gravity of a single phase gas system and a two phase gas/liquid system in an enclosed circular cylinder heated suddenly and nonuniformly from above was investigated. Flow visualization was used to obtain qualitative data on both systems. The use of thermochromatic liquid crystal particles as liquid phase flow tracers was evaluated as a possible means of simultaneously gathering both flow pattern and temperature gradient data for the two phase system. The results of the flow visualization experiments performed on both systems can be used to gain a better understanding of the behavior of such systems in a reduced gravity environment and aid in the verification of a numerical model of the system.

M-type potassium conductance controls the emergence of neural phase codes: a combined experimental and neuron modelling study

PubMed Central

Kwag, Jeehyun; Jang, Hyun Jae; Kim, Mincheol; Lee, Sujeong

2014-01-01

Rate and phase codes are believed to be important in neural information processing. Hippocampal place cells provide a good example where both coding schemes coexist during spatial information processing. Spike rate increases in the place field, whereas spike phase precesses relative to the ongoing theta oscillation. However, what intrinsic mechanism allows for a single neuron to generate spike output patterns that contain both neural codes is unknown. Using dynamic clamp, we simulate an in vivo-like subthreshold dynamics of place cells to in vitro CA1 pyramidal neurons to establish an in vitro model of spike phase precession. Using this in vitro model, we show that membrane potential oscillation (MPO) dynamics is important in the emergence of spike phase codes: blocking the slowly activating, non-inactivating K+ current (IM), which is known to control subthreshold MPO, disrupts MPO and abolishes spike phase precession. We verify the importance of adaptive IM in the generation of phase codes using both an adaptive integrate-and-fire and a Hodgkin–Huxley (HH) neuron model. Especially, using the HH model, we further show that it is the perisomatically located IM with slow activation kinetics that is crucial for the generation of phase codes. These results suggest an important functional role of IM in single neuron computation, where IM serves as an intrinsic mechanism allowing for dual rate and phase coding in single neurons. PMID:25100320

Synthesis of a single phase of high-entropy Laves intermetallics in the Ti-Zr-V-Cr-Ni equiatomic alloy

NASA Astrophysics Data System (ADS)

Yadav, T. P.; Mukhopadhyay, Semanti; Mishra, S. S.; Mukhopadhyay, N. K.; Srivastava, O. N.

2017-12-01

The high-entropy Ti-Zr-V-Cr-Ni (20 at% each) alloy consisting of all five hydride-forming elements was successfully synthesised by the conventional melting and casting as well as by the melt-spinning technique. The as-cast alloy consists entirely of the micron size hexagonal Laves Phase of C14 type; whereas, the melt-spun ribbon exhibits the evolution of nanocrystalline Laves phase. There was no evidence of any amorphous or any other metastable phases in the present processing condition. This is the first report of synthesising a single phase of high-entropy complex intermetallic compound in the equiatomic quinary alloy system. The detailed characterisation by X-ray diffraction, scanning and transmission electron microscopy and energy-dispersive X-ray spectroscopy confirmed the existence of a single-phase multi-component hexagonal C14-type Laves phase in all the as-cast, melt-spun and annealed alloys. The lattice parameter a = 5.08 Å and c = 8.41 Å was determined from the annealed material (annealing at 1173 K). The thermodynamic calculations following the Miedema's approach support the stability of the high-entropy multi-component Laves phase compared to that of the solid solution or glassy phases. The high hardness value (8.92 GPa at 25 g load) has been observed in nanocrystalline high-entropy alloy ribbon without any cracking. It implies that high-yield strength ( 3.00 GPa) and the reasonable fracture toughness can be achieved in this high-entropy material.

Advanced Microwave Ferrite Research (AMFeR): Phase Two

DTIC Science & Technology

2006-12-31

motion for the single crystal LPE films were a qualitative success, but a complete set of parameters for these films has not yet been achieved. Key...biasing field. In order to address these issues, we investigated and optimized a new LPE flux system to grow high quality thick films and bulk single...self-biased circulators. III. Methodology: BaM thick film and bulk single crystal growth by LPE process BaFe 120 19 flux melt was prepared from a

Vortex-induced vibration for an isolated circular cylinder under the wake interference of an oscillating airfoil: Part II. Single degree of freedom

NASA Astrophysics Data System (ADS)

Zhang, G. Q.; Ji, L. C.; Hu, X.

2017-04-01

The vortex-induced vibration behind an isolated cylinder under the wake interference of an oscillating airfoil at different oscillating frequencies and amplitudes have been studied numerically. Our previous research [11] mainly focused on the two degree of freedom vibration problem, several types of the phase portraits of the displacement have been newly found, including the "half -8″ and "cone-net" types as reduced velocity increases. At present, we have continued the research to the single degree of freedom vibration, the corresponding results had been found that under the wake of the free steady flow, as the reduced velocity increases, the phase portraits displacements of the single degree of freedom vibrating cylinder will begin to rotate counterclockwise from the first and third quadrants to the second and fourth quadrants in a Cartesian coordinate system. Under the wake of the oscillating airfoil, the single bending curve and the single closed orbit (double "8-shape" like) of the displacements are newly found in the drag and thrust producing cases respectively. Except this, the two triplets of vortices have also been newly found in the pair and single plus pair wakes at each cycle. The vorticity dynamics behind the vibrating cylinder together with the corresponding force variations have also been obtained computationally and analyzed in details.

Microscopic studies of polycrystalline nanoparticle growth in free space

NASA Astrophysics Data System (ADS)

Mohan, A.; Kaiser, M.; Verheijen, M. A.; Schropp, R. E. I.; Rath, J. K.

2017-06-01

We have extensively studied by multiple microscopic techniques the growth and crystallization of silicon nanoparticles in pulsed SiH4/Ar plasmas. We observe that the crystallinity of the particles can be tuned from amorphous to crystalline by altering the plasma ON time, tON. Three phases can be identified as a function of tON. Microscopic studies reveal that, in the initial gas phase (phase I) single particles of polycrystalline nature are formed which according to our hypothesis grow out of a single nucleus. The individual crystallites of the polycrystalline particles become bigger crystalline regions which marks the onset of cauliflower shaped particles (phase II). At longer tON (phase III) distinct cauliflower particles are formed by the growth of these crystalline regions by local epitaxy.

Thermodynamic guiding principles in selective synthesis of strontium iridate Ruddlesden-Popper epitaxial Films

DOE PAGES

Nishio, Kazunori; Hwang, Harold Y.; Hikita, Yasuyuki

2016-03-10

We demonstrate the selective fabrication of Ruddlesden-Popper (RP) type SrIrO 3, Sr 3Ir 2O 7, and Sr 2IrO 4 epitaxialthin films from a single SrIrO 3 target using pulsed laser deposition(PLD). We identified that the growth conditions stabilizing each phase directly map onto the phase diagram expected from thermodynamic equilibria. This approach allows precise cation stoichiometry control as evidenced by the stabilization of single phase Sr 3Ir 2O 7 for the first time, overcoming the close thermodynamic stability between neighboring RP phases. Furthermore, despite the non-equilibrium nature of PLD, these results highlight the importance of thermodynamic guiding principles to strategicallymore » synthesize the targeted phase in complex oxide thin films.« less

Updating the phase diagram of the archetypal frustrated magnet Gd3Ga5O12

NASA Astrophysics Data System (ADS)

Deen, P. P.; Florea, O.; Lhotel, E.; Jacobsen, H.

2015-01-01

The applied magnetic field and temperature phase diagram of the archetypal frustrated magnet, Gd3Ga5O12 , has been reinvestigated using single-crystal magnetometry and polarized neutron diffraction. The updated phase diagram is substantially more complicated than previously reported and can be understood in terms of competing interactions with loops of spins, trimers, and decagons, in addition to competition and interplay between antiferromagnetic, incommensurate, and ferromagnetic order. Several additional distinct phase boundaries are presented. The phase diagram centers around a multiphase convergence to a single point at 0.9 T and ˜0.35 K, below which, in temperature, a very narrow magnetically disordered region exists. These data illustrate the richness and diversity that arise from frustrated exchange on the three-dimensional hyperkagome lattice.

Wideband tunable laser phase noise reduction using single sideband modulation in an electro-optical feed-forward scheme.

PubMed

Aflatouni, Firooz; Hashemi, Hossein

2012-01-15

A wideband laser phase noise reduction scheme is introduced where the optical field of a laser is single sideband modulated with an electrical signal containing the discriminated phase noise of the laser. The proof-of-concept experiments on a commercially available 1549 nm distributed feedback laser show linewidth reduction from 7.5 MHz to 1.8 kHz without using large optical cavity resonators. This feed-forward scheme performs wideband phase noise cancellation independent of the light source and, as such, it is compatible with the original laser source tunability without requiring tunable optical components. By placing the proposed phase noise reduction system after a commercial tunable laser, a tunable coherent light source with kilohertz linewidth over a tuning range of 1530-1570 nm is demonstrated.

Manipulation of Liquids Using Phased Array Generation of Acoustic Radiation Pressure

NASA Technical Reports Server (NTRS)

Oeftering, Richard C. (Inventor)

2000-01-01

A phased array of piezoelectric transducers is used to control and manipulate contained as well as uncontained fluids in space and earth applications. The transducers in the phased array are individually activated while being commonly controlled to produce acoustic radiation pressure and acoustic streaming. The phased array is activated to produce a single pulse, a pulse burst or a continuous pulse to agitate, segregate or manipulate liquids and gases. The phased array generated acoustic radiation pressure is also useful in manipulating a drop, a bubble or other object immersed in a liquid. The transducers can be arranged in any number of layouts including linear single or multi- dimensional, space curved and annular arrays. The individual transducers in the array are activated by a controller, preferably driven by a computer.

Phase transition in organic-inorganic perovskite (C9H19NH3)2 PbI2Br2 of long-chain alkylammonium

NASA Astrophysics Data System (ADS)

Abid, H.; Trigui, A.; Mlayah, A.; Hlil, E. K.; Abid, Y.

2012-01-01

Single perovskite slab alkylammonium lead iodides bromides (C9H19NH3)2PbI2Br2 is a new member of the family of hybrid organic-inorganic perovskite compounds. It exhibits a single structural phase transition with changes in the conformation of alkylammonium chains below room temperature. Differential scanning calorimetry (DSC), powder X-ray diffraction and FT-Raman spectroscopy were used to investigate this phase transition. These changes were characterized by a decreased conformational disorder of the methylene units of the alkyl chains. Phase transition was examined in light of the interesting optical properties of this material, as well as the relevance of this system as models for phase transitions in lipid bilayers.

24 CFR 3280.806 - Receptacle outlets.

Code of Federal Regulations, 2011 CFR

2011-04-01

... appliances, be parallel-blade, 15-ampere, 125-volt, either single or duplex. (b) All 120 volt single phase... 24 Housing and Urban Development 5 2011-04-01 2011-04-01 false Receptacle outlets. 3280.806 Section 3280.806 Housing and Urban Development Regulations Relating to Housing and Urban Development...

24 CFR 3280.806 - Receptacle outlets.

Code of Federal Regulations, 2013 CFR

2013-04-01

... appliances, be parallel-blade, 15-ampere, 125-volt, either single or duplex. (b) All 120 volt single phase... 24 Housing and Urban Development 5 2013-04-01 2013-04-01 false Receptacle outlets. 3280.806 Section 3280.806 Housing and Urban Development Regulations Relating to Housing and Urban Development...

24 CFR 3280.806 - Receptacle outlets.

Code of Federal Regulations, 2010 CFR

2010-04-01

... appliances, be parallel-blade, 15-ampere, 125-volt, either single or duplex. (b) All 120 volt single phase... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Receptacle outlets. 3280.806 Section 3280.806 Housing and Urban Development Regulations Relating to Housing and Urban Development...

24 CFR 3280.806 - Receptacle outlets.

Code of Federal Regulations, 2012 CFR

2012-04-01

... appliances, be parallel-blade, 15-ampere, 125-volt, either single or duplex. (b) All 120 volt single phase... 24 Housing and Urban Development 5 2012-04-01 2012-04-01 false Receptacle outlets. 3280.806 Section 3280.806 Housing and Urban Development Regulations Relating to Housing and Urban Development...

Thermodynamics around the first-order ferromagnetic phase transition of Fe2P single crystals

NASA Astrophysics Data System (ADS)

Hudl, M.; Campanini, D.; Caron, L.; Höglin, V.; Sahlberg, M.; Nordblad, P.; Rydh, A.

2014-10-01

The specific heat and thermodynamics of Fe2P single crystals around the first-order paramagnetic to ferromagnetic (FM) phase transition at TC≃217 K are empirically investigated. The magnitude and direction of the magnetic field relative to the crystal axes govern the derived H -T phase diagram. Strikingly different phase contours are obtained for fields applied parallel and perpendicular to the c axis of the crystal. In parallel fields, the FM state is stabilized, while in perpendicular fields the phase transition is split into two sections, with an intermediate FM phase where there is no spontaneous magnetization along the c axis. The zero-field transition displays a textbook example of a first-order transition with different phase stability limits on heating and cooling. The results have special significance since Fe2P is the parent material to a family of compounds with outstanding magnetocaloric properties.

Magnetic Correlations and Pairing in the 1/5-Depleted Square Lattice Hubbard Model

DOE PAGES

Khatemi, Ehsan; Singh, Rajiv R. P.; Pickett, Warren E.; ...

2014-09-04

We study the single-orbital Hubbard model on the 1/5-depleted square-lattice geometry, which arises in such diverse systems as the spin-gap magnetic insulator CaV 4O 9 and ordered-vacancy iron selenides, presenting new issues regarding the origin of both magnetic ordering and superconductivity in these materials. We find a rich phase diagram that includes a plaquette singlet phase, a dimer singlet phase, a Néel and a block-spin antiferromagnetic phase, and stripe phases. Quantum Monte Carlo simulations show that the dominant pairing correlations at half filling change character from d wave in the plaquette phase to extended s wave upon transition to themore » Néel phase. These findings have intriguing connections to iron-based superconductors, and suggest that some physics of multiorbital systems can be captured by a single-orbital model at different dopings.« less

Atomic Migration Induced Crystal Structure Transformation and Core-Centered Phase Transition in Single Crystal Ge2Sb2Te5 Nanowires.

PubMed

Lee, Jun-Young; Kim, Jeong-Hyeon; Jeon, Deok-Jin; Han, Jaehyun; Yeo, Jong-Souk

2016-10-12

A phase change nanowire holds a promise for nonvolatile memory applications, but its transition mechanism has remained unclear due to the analytical difficulties at atomic resolution. Here we obtain a deeper understanding on the phase transition of a single crystalline Ge 2 Sb 2 Te 5 nanowire (GST NW) using atomic scale imaging, diffraction, and chemical analysis. Our cross-sectional analysis has shown that the as-grown hexagonal close-packed structure of the single crystal GST NW transforms to a metastable face-centered cubic structure due to the atomic migration to the pre-existing vacancy layers in the hcp structure going through iterative electrical switching. We call this crystal structure transformation "metastabilization", which is also confirmed by the increase of set-resistance during the switching operation. For the set to reset transition between crystalline and amorphous phases, high-resolution imaging indicates that the longitudinal center of the nanowire mainly undergoes phase transition. According to the atomic scale analysis of the GST NW after repeated electrical switching, partial crystallites are distributed around the core-centered amorphous region of the nanowire where atomic migration is mainly induced, thus potentially leading to low power electrical switching. These results provide a novel understanding of phase change nanowires, and can be applied to enhance the design of nanowire phase change memory devices for improved electrical performance.

Multiple scattering of broadband terahertz pulses

NASA Astrophysics Data System (ADS)

Pearce, Jeremiah Glen

Propagation of single-cycle terahertz (THz) pulses through a random medium leads to dramatic amplitude and phase variations of the electric field because of multiple scattering. We present the first set of experiments that investigate the propagation of THz pulses through scattering media. The scattering of short pulses is a relevant subject to many communities in science and engineering, because the properties of multiply scattered or diffuse waves provide insights into the characteristics of the random medium. For example, the depolarization of diffuse waves has been used to form images of objects embedded in inhomogeneous media. Most of the previous scattering experiments have used narrowband optical radiation where measurements are limited to time averaged intensities or autocorrelation quantities, which contain no phase information of the pulses. In the experiments presented here, a terahertz time-domain spectrometer (THz-TDS) is used. A THz-TDS propagates single-cycle sub-picosecond pulses with bandwidths of over 1 THz into free space. The THz-TDS is a unique tool to study such phenomena, because it provides access to both the intensity and phase of those pulses through direct measurement of the temporal electric field. Because of the broad bandwidth and linear phase of the pulses, it is possible to simultaneously study Rayleigh scattering and the short wavelength limit in a single measurement. We study the diffusion of broadband single-cycle THz pulses by propagating the pulses through a highly scattering medium. Using the THz-TDS, time-domain measurements provide information on the statistics of both the amplitude and phase of the diffusive waves. We develop a theoretical description, suitable for broadband radiation, which accurately describes the experimental results. We measure the time evolution of the degree of polarization, and directly correlate it with the single-scattering regime in the time domain. Measurements of the evolution of the temporal phase of the radiation demonstrate that the average spectral content depends on the state of polarization. In the case of broadband radiation, this effect distinguishes photons that have been scattered only a few times from those that are propagating diffusively.