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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 847 records · Page 47
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

High-precision instrument for measuring the surface tension, viscosity and surface viscoelasticity of liquids using ripplon surface laser-light scattering with tunable wavelength selection

Here we describe our new high-precision instrument that simultaneously measures the surface tension, viscosity, and surface viscoelasticity of liquids. The instrument works on the ripplon surface-laser light scattering principle and operates with an automatically tunable selection of ripplon wavelength from 4 to 1500 μm, which corresponds to the frequency range of observing surface phenomena from approximately 400 Hz to 3 MHz in the case of water. The heterodyne technique instrument uses a reference laser beam which intersects at an arbitrarily adjustable angle with a vertically directed probing beam. For the determination of the wavelength of selected ripplons we substituted with the interference fringe spacing, measured using a high-resolution beam profiler. To extract reliable surface tension and viscosity data from the experimentally obtained spectrum shape for a selected wavelength of ripplon, we developed an algorithm to calculate the exact solution of the dispersion equation. The uncertainties of surface tension and viscosity measurement were confirmed through the measurement of seven pure Newtonian liquids at 25 °C measured with the selected wavelength of ripplon from 40 μm to 467 μm. To verify the genuine capability of the tunable wavelength selection of ripplon, we measured the surface elasticity of soluble surface molecular layers spread on pentanoic acid solutions.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2014

A high precision, compact electromechanical ground rotation sensor

We present a mechanical rotation sensor consisting of a balance pivoting on a tungsten carbide knife edge. These sensors are important for precision seismic isolation systems, as employed in land-based gravitational wave interferometers and for the new field of rotational seismology. The position sensor used is an air-core linear variable differential transformer with a demonstrated noise floor of 1 × 10{sup −11}m/√( Hz ). We describe the instrument construction and demonstrate low noise operation with a noise floor upper bound of 5.7 × 10{sup −9} rad /√( Hz ) at 10 mHz and 6.4 × 10{sup −10} rad /√( Hz ) at 0.1 Hz. The performance of the knife edge hinge is compatible with a behaviorur free of noise from dislocation self-organized criticality.

42 ENGINEERING↗
DOE OSTI2014

Precisely predicting and designing the elasticity of metallic glasses

We reveal that the elastic moduli of metallic glasses (MGs) invariably vary in a much steeper manner than that predicted by the conventional “rule of mixtures” in individual alloy systems. Such deviations are proved to originate fundamentally from their disordered atomic structures and intrinsic local heterogeneities. By treating the MGs as atomic-level dual phase hybrids, we further propose universal relations to be capable of precisely predicting and designing the elastic constants of MGs. This may contribute to the development of MGs with intended properties and behaviors, and allow new understandings on the structures and properties as well as their relationships in MGs.

42 ENGINEERING↗
DOE OSTI2014

A widely tunable 10-μm quantum cascade laser phase-locked to a state-of-the-art mid-infrared reference for precision molecular spectroscopy

We report the coherent phase-locking of a quantum cascade laser (QCL) at 10-μm to the secondary frequency standard of this spectral region, a CO{sub 2} laser stabilized on a saturated absorption line of OsO{sub 4}. The stability and accuracy of the standard are transferred to the QCL resulting in a line width of the order of 10 Hz, and leading to the narrowest QCL to date. The locked QCL is then used to perform absorption spectroscopy spanning 6 GHz of NH{sub 3} and methyltrioxorhenium, two species of interest for applications in precision measurements.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2014

Multichannel low power time-to-digital converter card with 21 ps precision and full scale range up to 10 μs

We present a Time-to-Digital Converter (TDC) card with a compact form factor, suitable for multichannel timing instruments or for integration into more complex systems. The TDC Card provides 10 ps timing resolution over the whole measurement range, which is selectable from 160 ns up to 10 μs, reaching 21 ps rms precision, 1.25% LSB rms differential nonlinearity, up to 3 Mconversion/s with 400 mW power consumption. The I/O edge card connector provides timing data readout through either a parallel bus or a 100 MHz serial interface and further measurement information like input signal rate and valid conversion rate (typically useful for time-correlated single-photon counting application) through an independent serial link.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2014

Precision spectral manipulation: A demonstration using a coherent optical memory

The ability to coherently spectrally manipulate quantum information has the potential to improve qubit rates across quantum channels and find applications in optical quantum computing. Here we present experiments that use a multi-element solenoid combined with the three-level gradient echo memory scheme to perform precision spectral manipulation of optical pulses. If applied in a quantum information network, these operations would enable frequency-based multiplexing of qubits.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2015

Precise and direct method for the measurement of the torsion spring constant of the atomic force microscopy cantilevers

A direct method for the evaluation of the torsional spring constants of the atomic force microscope cantilevers is presented in this paper. The method uses a nanoindenter to apply forces at the long axis of the cantilever and in the certain distance from it. The torque vs torsion relation is then evaluated by the comparison of the results of the indentations experiments at different positions on the cantilever. Next, this relation is used for the precise determination of the torsional spring constant of the cantilever. The statistical analysis shows that the standard deviation of the calibration measurements is equal to approximately 1%. Furthermore, a simple method for calibration of the photodetector’s lateral response is proposed. The overall procedure of the lateral calibration constant determination has the accuracy approximately equal to 10%.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2015

High-precision laser spectroscopy of the CO A{sup 1}Π - X{sup 1}Σ{sup +} (2,0), (3,0), and (4,0) bands

High-precision two-photon Doppler-free frequency measurements have been performed on the CO A{sup 1}Π - X{sup 1}Σ{sup +} fourth-positive system (2,0), (3,0), and (4,0) bands. Absolute frequencies of forty-three transitions, for rotational quantum numbers up to J = 5, have been determined at an accuracy of 1.6 × 10{sup −3} cm{sup −1}, using advanced techniques of two-color 2 + 1’ resonance-enhanced multi-photon ionization, Sagnac interferometry, frequency-chirp analysis on the laser pulses, and correction for AC-Stark shifts. The accurate transition frequencies of the CO A{sup 1}Π - X{sup 1}Σ{sup +} system are of relevance for comparison with astronomical data in the search for possible drifts of fundamental constants in the early universe. The present accuracies in laboratory wavelengths of Δλ/λ = 2 × 10{sup −8} may be considered exact for the purpose of such comparisons.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Hysteresis-free high-temperature precise bimorph actuators produced by direct bonding of lithium niobate wafers

The current paper presents a piezoelectric bimorph actuator produced by direct bonding of lithium niobate wafers with the mirrored Y and Z axes. Direct bonding technology allowed to fabricate bidomain plate with precise positioning of ideally flat domain boundary. By optimizing the cutting angle (128° Y-cut), the piezoelectric constant became as large as 27.3 pC/N. Investigation of voltage dependence of bending displacement confirmed that bimorph actuator has excellent linearity and hysteresis-free. Decrease of the applied voltage down to mV range showed the perfect linearity up to the sub-nm deflection amplitude. The frequency and temperature dependences of electromechanical transmission coefficient in wide temperature range (from 300 to 900 K) were investigated.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Optoelectronic transport properties in amorphous/crystalline silicon solar cell heterojunctions measured by frequency-domain photocarrier radiometry: Multi-parameter measurement reliability and precision studies

A theoretical one-dimensional two-layer linear photocarrier radiometry (PCR) model including the presence of effective interface carrier traps was used to evaluate the transport parameters of p-type hydrogenated amorphous silicon (a-Si:H) and n-type crystalline silicon (c-Si) passivated by an intrinsic hydrogenated amorphous silicon (i-layer) nanolayer. Several crystalline Si heterojunction structures were examined to investigate the influence of the i-layer thickness and the doping concentration of the a-Si:H layer. The experimental data of a series of heterojunction structures with intrinsic thin layers were fitted to PCR theory to gain insight into the transport properties of these devices. The quantitative multi-parameter results were studied with regard to measurement reliability (uniqueness) and precision using two independent computational best-fit programs. The considerable influence on the transport properties of the entire structure of two key parameters that can limit the performance of amorphous thin film solar cells, namely, the doping concentration of the a-Si:H layer and the i-layer thickness was demonstrated. It was shown that PCR can be applied to the non-destructive characterization of a-Si:H/c-Si heterojunction solar cells yielding reliable measurements of the key parameters.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2015

Tip localization of an atomic force microscope in transmission microscopy with nanoscale precision

Since the atomic force microscope (AFM) has evolved into a general purpose platform for mechanical experiments at the nanoscale, the need for a simple and generally applicable localization of the AFM cantilever in the reference frame of an optical microscope has grown. Molecular manipulations like in single molecule cut and paste or force spectroscopy as well as tip mediated nanolithography are prominent examples for the broad variety of applications implemented to date. In contrast to the different kinds of superresolution microscopy where fluorescence is used to localize the emitter, we, here, employ the absorbance of the tip to localize its position in transmission microscopy. We show that in a low aperture illumination, the tip causes a significant reduction of the intensity in the image plane of the microscope objective when it is closer than a few hundred nm. By independently varying the z-position of the sample slide, we could verify that this diffraction limited image of the tip is not caused by a near field effect but is rather caused by the absorbance of the transmitted light in the low apex needle-like tip. We localized the centroid position of this tip image with a precision of better than 6 nm and used it in a feedback loop to position the tip into nano-apertures of 110 nm radius. Single-molecule force spectroscopy traces on the unfolding of individual green fluorescent proteins within the nano-apertures showed that their center positions were repeatedly approached with very high fidelity leaving the specific handle chemistry on the tip’s surface unimpaired.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2015

Precise energy eigenvalues of hydrogen-like ion moving in quantum plasmas

The analytic form of the electrostatic potential felt by a slowly moving test charge in quantum plasma is developed. It has been shown that the electrostatic potential is composed of two parts: the Debye-Huckel screening term and the near-field wake potential. The latter depends on the velocity of the test charge as well as on the number density of the plasma electrons. Rayleigh-Ritz variational calculation has been done to estimate precise energy eigenvalues of hydrogen-like carbon ion under such plasma environment. A detailed analysis shows that the energy levels gradually move to the continuum with increasing plasma electron density while the level crossing phenomenon has been observed with the variation of ion velocity.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2015

Note: Compact and light displacement sensor for a precision measurement system in large motion

We developed a compact and light displacement sensor applicable to systems that require wide range motions of its sensing device. The proposed sensor utilized the optical pickup unit of the optical disk drive, which has been used applied to atomic force microscopy (AFM) because of its compactness and lightness as well as its high performance. We modified the structure of optical pickup unit and made the compact sensor driver attachable to a probe head of AFM to make large rotation. The feasibilities of the developed sensor for a general probe-moving measurement device and for probe-rotating AFM were verified. Moreover, a simple and precise measurement of alignment between centers of rotator and probe tip in probe-rotation AFM was experimentally demonstrated using the developed sensor.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2015

High precision quantum-chemical treatment of adsorption: Benchmarking physisorption of molecular hydrogen on graphane

A multilevel hierarchical ab initio protocol for calculating adsorption on non-conducting surfaces is presented. It employs fully periodic treatment, which reaches local Møller-Plesset perturbation theory of second order (MP2) with correction for the basis set incompleteness via the local F12 technique. Post-MP2 corrections are calculated using finite clusters. That includes the coupled cluster treatment in the local and canonical frameworks (up to perturbative quadruples) and correlated core (with MP2). Using this protocol, the potential surface of hydrogen molecules adsorbed on graphane was computed. According to the calculations, hydrogen molecules are adsorbed on graphane in a perpendicular to the surface orientation with the minimum of the potential surface of around −3.6 kJ/mol located at the distance of 3.85 Å between the bond center of the hydrogen molecule and the mid-plane of graphane. The adsorption sites along the path from the downward-pointing carbon to the ring center of the graphane are energetically virtually equally preferable, which can enable nearly free translations of hydrogen molecules along these paths. Consequently, the hydrogen molecules on graphane most likely form a non-commensurate monolayer. The analysis of the remaining errors reveals a very high accuracy of the computed potential surface with an error bar of a few tenths of a kJ/mol. The obtained results are a high-precision benchmark for further theoretical and experimental studies of hydrogen molecules interacting with graphane.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Peculiarities of high-overtone transition probabilities in carbon monoxide revealed by high-precision calculation

In the recent work devoted to the calculation of the rovibrational line list of the CO molecule [G. Li et al., Astrophys. J., Suppl. Ser. 216, 15 (2015)], rigorous validation of the calculated parameters including intensities was carried out. In particular, the Normal Intensity Distribution Law (NIDL) [E. S. Medvedev, J. Chem. Phys. 137, 174307 (2012)] was employed for the validation purposes, and it was found that, in the original CO line list calculated for large changes of the vibrational quantum number up to Δn = 41, intensities with Δn > 11 were unphysical. Therefore, very high overtone transitions were removed from the published list in Li et al. Here, we show how this type of validation is carried out and prove that the quadruple precision is indispensably required to predict the reliable intensities using the conventional 32-bit computers. Based on these calculations, the NIDL is shown to hold up for the 0 → n transitions till the dissociation limit around n = 83, covering 45 orders of magnitude in the intensity. The low-intensity 0 → n transition predicted in the work of Medvedev [Determination of a new molecular constant for diatomic systems. Normal intensity distribution law for overtone spectra of diatomic and polyatomic molecules and anomalies in overtone absorption spectra of diatomic molecules, Institute of Chemical Physics, Russian Academy of Sciences, Chernogolovka, 1984] at n = 5 is confirmed, and two additional “abnormal” intensities are found at n = 14 and 23. Criteria for the appearance of such “anomalies” are formulated. The results could be useful to revise the high-overtone molecular transition probabilities provided in spectroscopic databases.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2015

Prospects of photonic nanojets for precise exposure on microobjects

We report on the new optical tool for precise manipulation of various microobjects. This tool is referred to as a “photonic nanojet” (PJ) and corresponds to specific spatially localized and high-intensity area formed near micron-sized transparent spherical dielectric particles illuminated by a visible laser radiation The descriptive analysis of the morphological shapes of photonic nanojets is presented. The PJ shape characterization is based on the numerical calculations of the near-field distribution according to the Mie theory and accounts for jet dimensions and shape complexity.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2015

Precise measurement of cosmic ray fluxes with the AMS-02 experiment

The AMS-02 detector is a large acceptance magnetic spectrometer operating onboard the International Space Station since May 2011. The main goals of the detector are the search for antimatter and dark matter in space, as well as the measurement of cosmic ray composition and flux. In this document we present precise measurements of cosmic ray positrons, electrons and protons, collected during the first 30 months of operations.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗