ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • American Institute of Physics (AIP)  (241,959)
Collection
Years
  • 1
    Journal cover
    Unknown
    American Institute of Physics (AIP)
    Online: 1(1).2016 –
    Publisher: American Institute of Physics (AIP)
    Electronic ISSN: 2378-0967
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Journal cover
    Unknown
    American Institute of Physics (AIP)
    Online: 1.2013 –
    Publisher: American Institute of Physics (AIP)
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Keywords: Werkstoffkunde
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Journal cover
    Unknown
    American Institute of Physics (AIP)
    Online: 1(1).2014 –
    Publisher: American Institute of Physics (AIP)
    Electronic ISSN: 1931-9401
    Topics: Physics
    Keywords: Allgemeine Physik
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Journal cover
    Unknown
    American Institute of Physics (AIP)
    Online: 1.1962 –
    Publisher: American Institute of Physics (AIP)
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Journal cover
    Unknown
    American Institute of Physics (AIP)
    Online: 1.1975 – 29.2003
    Formerly as: Soviet Astronomy / Letters. A translation of the Astronomical journal of the Soviet Academy of Sciences of the USSR  (1975–1992)
    Publisher: American Institute of Physics (AIP)
    Print ISSN: 0360-0327 , 1063-7737
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Online: 1.1969 – 34.2002
    Publisher: American Institute of Physics (AIP)
    Print ISSN: 0002-7537
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Journal cover
    Unknown
    American Institute of Physics (AIP)
    Online: 1(1).1970 –
    Publisher: American Institute of Physics (AIP)
    Print ISSN: 0094-243X
    Electronic ISSN: 1551-7616
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Journal cover
    Unknown
    American Crystallographic Association (ACA) | American Institute of Physics (AIP)
    Online: 1(1).2014 –
    Publisher: American Crystallographic Association (ACA) , American Institute of Physics (AIP)
    Electronic ISSN: 2329-7778
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Journal cover
    Unknown
    American Institute of Physics (AIP)
    Online: 1.1933 –
    Publisher: American Institute of Physics (AIP)
    Print ISSN: 0021-9606
    Electronic ISSN: 1089-7690
    Topics: Chemistry and Pharmacology , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Journal cover
    Unknown
    American Institute of Physics (AIP)
    Online: 36.2004 –
    Publisher: American Institute of Physics (AIP)
    Print ISSN: 0148-5857
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    Journal cover
    Unknown
    American Institute of Physics (AIP) | American Crystallographic Association (ACA)
    Online: 1.2011 –
    Publisher: American Institute of Physics (AIP) , American Crystallographic Association (ACA)
    Electronic ISSN: 2158-3226
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    Journal cover
    Unknown
    American Institute of Physics (AIP)
    Online: 1.1991 –
    Publisher: American Institute of Physics (AIP)
    Print ISSN: 1054-1500
    Electronic ISSN: 1089-7682
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    Journal cover
    Unknown
    American Institute of Physics (AIP) | IEEE Computer Society | Institute of Electrical and Electronics Engineers (IEEE)
    Online: 1.1999 –
    Publisher: American Institute of Physics (AIP) , IEEE Computer Society , Institute of Electrical and Electronics Engineers (IEEE)
    Print ISSN: 1521-9615
    Electronic ISSN: 1558-366X
    Topics: Computer Science , Natural Sciences in General , Technology
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    Journal cover
    Unknown
    American Institute of Physics (AIP)
    Online: 1.1958 –
    Formerly as: Physics of Fluids A: Fluid Dynamics ; Physics of Fluids B: Plasma Physics  (1989–1993)
    Publisher: American Institute of Physics (AIP)
    Print ISSN: 0031-9171 , 1070-6631
    Electronic ISSN: 1089-7666
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    Journal cover
    Unknown
    American Institute of Physics (AIP)
    Online: 1(1).1989 – 5(12).1993
    Online: 1(1).1989 – 5(12).1993
    Publisher: American Institute of Physics (AIP)
    Print ISSN: 0899-8213
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    Journal cover
    Unknown
    American Institute of Physics (AIP)
    Online: 1.2009 –
    Publisher: American Institute of Physics (AIP)
    Electronic ISSN: 1941-7012
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    Journal cover
    Unknown
    Society of Rheology (SoR) | American Institute of Physics (AIP)
    Online: 1(1).1929 –
    Formerly as: Transactions of the Society of Rheology  (1957–1977)
    Publisher: Society of Rheology (SoR) , American Institute of Physics (AIP)
    Print ISSN: 0038-0032 , 0097-0360 , 0148-6055
    Electronic ISSN: 1520-8516
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    Journal cover
    Unknown
    American Institute of Physics (AIP)
    Online: 52.1999 –
    Print: 39(7).1986 – 45.1992 (Location: A17, Kompaktmagazin, 58/6-7)
    Print: 44.1991 – 63.2010 (Location: A43, Archiv)
    Print: 46.1993 – 71.2018 (Location: A17, Kompaktmagazin, 58/6-7)
    Publisher: American Institute of Physics (AIP)
    Print ISSN: 0031-9228
    Electronic ISSN: 1945-0699
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    Journal cover
    Unknown
    American Institute of Physics (AIP)
    Online: 1.1960 –
    Publisher: American Institute of Physics (AIP)
    Print ISSN: 0022-2488
    Electronic ISSN: 1089-7658
    Topics: Mathematics , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    Journal cover
    Unknown
    American Institute of Physics (AIP)
    Online: 1(1).1989 – 5(12).1993
    Online: 1(1).1989 – 5(12).1993
    Publisher: American Institute of Physics (AIP)
    Print ISSN: 0899-8221
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    Journal cover
    Unknown
    American Institute of Physics (AIP)
    Online: 1.1994 –
    Publisher: American Institute of Physics (AIP)
    Print ISSN: 1070-664X
    Electronic ISSN: 1089-7674
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    Journal cover
    Unknown
    Laser Institute of America (LIA) | American Institute of Physics (AIP)
    Online: 1(1).1988 –
    Publisher: Laser Institute of America (LIA) , American Institute of Physics (AIP)
    Print ISSN: 1042-346X
    Electronic ISSN: 1938-1387
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    Journal cover
    Unknown
    American Institute of Physics (AIP)
    Online: 1.1931 –
    Formerly as: Physics  (1931–1936)
    Publisher: American Institute of Physics (AIP)
    Print ISSN: 0021-8979
    Electronic ISSN: 1089-7550
    Topics: Physics
    Acronym: JAP
    Abbreviation: J Appl Phys
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 24
    Journal cover
    Unknown
    American Institute of Physics (AIP) | früher: Elsevier
    Online: 1(1).2016 –
    Publisher: American Institute of Physics (AIP) , früher: Elsevier
    Print ISSN: 2468-2047
    Electronic ISSN: 2468-080X
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    Journal cover
    Unknown
    American Institute of Physics (AIP)
    Online: 23.1997 –
    Publisher: American Institute of Physics (AIP)
    Print ISSN: 1063-777X
    Electronic ISSN: 1090-6517
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 26
    Journal cover
    Unknown
    American Institute of Physics (AIP)
    Online: 1.1930 –
    Print: 28.1957 – 41.1970 (Location: A18, ---)
    Formerly as: Review of Scientific Instruments with Physics News and Views  (1933–1938)
    Publisher: American Institute of Physics (AIP)
    Print ISSN: 0034-6748
    Electronic ISSN: 1089-7623
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 27
    Publication Date: 2015-08-11
    Description: We demonstrate the real-time observation of phonon-polariton propagation in ferroelectric LiNbO 3 using a single-shot spectroscopic setup that employs an echelon mirror. The echelon mirror provides a spatially encoded time delay for the probe pulse; therefore, the ultrafast transient behavior of materials can be detected on a single-shot basis. Using optical Kerr gate apparatus, forward and backward propagating E -mode phonon-polaritons were simultaneously induced via an impulsive stimulated Raman scattering process, and subsequently, their dynamics were readily mapped in time-frequency space using heterodyne detection. The two phonon-polaritons appeared on opposite sides of the central probe wavelength and were symmetrically imaged against the ordinary and extraordinary probe lights. By taking into account coupling of the lowest E -mode phonon-polariton to a low-frequency relaxational mode, not only the phonon-polariton dispersion but also the wavevector dependence of the damping rate was unveiled and quantitatively evaluated.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 28
    Publication Date: 2015-08-11
    Description: This is the report on trap states in enhancement-mode AlGaN/GaN/AlGaN double heterostructures high electron mobility transistors by fluorine plasma treatment with different GaN channel layer thicknesses. Compared with the thick GaN channel layer sample, the thin one has smaller 2DEG concentration, lower electron mobility, lower saturation current, and lower peak transconductance, but it has a higher threshold voltage of 1.2 V. Deep level transient spectroscopy measurements are used to obtain the accurate capture cross section of trap states. By frequency dependent capacitance and conductance measurements, the trap state density of (1.98–2.56) × 10 12  cm −2 eV −1 is located at E T in a range of (0.37–0.44) eV in the thin sample, while the trap state density of (2.3–2.92) × 10 12  cm −2 eV −1 is located at E T in a range of (0.33–0.38) eV in the thick one. It indicates that the trap states in the thin sample are deeper than those in the thick one.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 29
    Publication Date: 2015-08-11
    Description: Vertically aligned nanocomposite (VAN) (La 0.7 Sr 0.3 MnO 3 ) 1−x :(CeO 2 ) x (LSMO:CeO 2 ) thin films have been grown on SrTiO 3 (001) substrates by pulsed laser deposition. Tunable magnetoresistance properties as well as microstructures are demonstrated in these VAN films by modulating the film composition (x = 0, 0.3, 0.4, 0.45, 0.5, and 0.55). The sample of x = 0.3 shows a large low-field magnetoresistance (LFMR) in a high temperature range, i.e., over 10% at the range of 280 K to 320 K under 1 T and with a peak value of ∼13.5% at 310 K. In addition, a vast enhancement of LFMR in a low temperature range of 20–150 K with peak of ≈34.3% at 45 K for 1 T could be achieved with x = 0.5. The enhanced LFMR properties can be attributed to both the phase boundary induced spin fluctuation and the magnetic tunneling effect through vertical ferromagnetic/insulator/ferromagnetic structures. The observed enhanced LFMR performance, especially at high temperatures, as well as its simple growth method, offers a great potential for LSMO:CeO 2 nanocomposites to be used in spintronic devices in a large temperature range.
    Print ISSN: 0021-8979
    Electronic ISSN: 1089-7550
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 30
    Publication Date: 2015-08-11
    Description: We present a new generalized scaling relationship accounting for relaxation processes of both the real and the imaginary parts of the complex dielectric permittivity data in a wide temperature range of dielectric media. It has been successfully used for experimental data related to various dynamics in liquid crystalline phases of: 4-bromobenzylidene-4′-pentyloxyanilin, 4-bromobenzylidene-4′-hexyloxyaniline, 4′-butyl-4-(2-methylbutoxy) azoxybenzene, and 4-ethyl-4′-octylazoxybenzene. Moreover, the scaling was checked for the theoretical data of Dissado-Hill cluster model. A comparison with earlier scaling, proposed by Nagel and Dendzik, is given.
    Print ISSN: 0021-8979
    Electronic ISSN: 1089-7550
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 31
    Publication Date: 2015-08-11
    Description: Focusing of surface phonon-polaritons propagating toward the tip of a cone and the edge of a wedge is theoretically analyzed and compared. Based on Maxwell's equations, explicit expressions for the dispersion relations in each structure are determined and solved numerically for a propagation parameter driving the surface phonon-polariton energy density. For conical and wedge structures of SiO 2 , it is found that: (1) the cone (wedge) supports the polariton focusing only for aperture angles in the interval 18 ° – 68 ° ( 21 ° – 51 ° ), and within the range of excitation frequencies from 32.1 THz (31.5 THz) to 33.9 THz (33.9 THz). In this frequency interval, the real part of the SiO 2 permittivity is negative and the presence of polaritons is significant. (2) The polariton focusing efficiency of both the cone and wedge reaches its maximum values at the critical frequency f cr = 33.6  THz and at different aperture angles of about α opt = 45 ° and α opt = 30 ° , respectively. (3) When the polaritons travel from 100 nm to 5 nm toward the tip of the cone with this optimum angle, their Poynting vector increases by a factor of 12, which is about four times larger than the corresponding one provided by the wedge and indicates that the cone is more efficient than the wedge for the focusing of surface phonon-polaritons.
    Print ISSN: 0021-8979
    Electronic ISSN: 1089-7550
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 32
    Publication Date: 2015-08-11
    Description: Surface plasmons can squeeze light into a deep-subwavelength space and generate abundant hot electrons in the nearby metallic regions, enabling a new paradigm of photoconversion by the way of hot electron collection. Unlike the visible spectral range concerned in previous literatures, we focus on the communication band and design the infrared hot-electron photodetectors with plasmonic metal-insulator-metal configuration by using full-wave finite-element method. Titanium dioxide-silver Schottky interface is employed to boost the low-energy infrared photodetection. The photodetection sensitivity is strongly improved by enhancing the plasmonic excitation from a rationally engineered metallic grating, which enables a strong unidirectional photocurrent. With a five-step electrical simulation, the optimized device exhibits an unbiased responsivity of ∼0.1 mA/W and an ultra-narrow response band (FWHM = 4.66 meV), which promises to be a candidate as the compact photodetector operating in communication band.
    Print ISSN: 0021-8979
    Electronic ISSN: 1089-7550
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 33
    Publication Date: 2015-08-11
    Description: A two-step method that combines homogeneous electron beam (EB) irradiation and thermal annealing has been developed to enhance the thermoelectric properties of nanocrystalline bismuth selenium telluride thin films. The thin films, prepared using a flash evaporation method, were treated with EB irradiation in a N 2 atmosphere at room temperature and an acceleration voltage of 0.17 MeV. Thermal annealing was performed under Ar/H 2 (5%) at 300 °C for 60 min. X-ray diffraction was used to determine that compositional phase separation between bismuth telluride and bismuth selenium telluride developed in the thin films exposed to higher EB doses and thermal annealing. We propose that the phase separation was induced by fluctuations in the distribution of selenium atoms after EB irradiation, followed by the migration of selenium atoms to more stable sites during thermal annealing. As a result, thin film crystallinity improved and mobility was significantly enhanced. This indicates that the phase separation resulting from the two-step method enhanced, rather than disturbed, the electron transport. Both the electrical conductivity and the Seebeck coefficient were improved following the two-step method. Consequently, the power factor of thin films that underwent the two-step method was enhanced to 20 times (from 0.96 to 21.0  μ W/(cm K 2 ) that of the thin films treated with EB irradiation alone.
    Print ISSN: 0021-8979
    Electronic ISSN: 1089-7550
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 34
    Publication Date: 2015-08-11
    Description: In this study, we developed a new method for in-situ pressure determination in multi-anvil, high-pressure apparatus using an acoustic travel time approach within the framework of acoustoelasticity. The ultrasonic travel times of polycrystalline Al 2 O 3 were calibrated against NaCl pressure scale up to 15 GPa and 900 °C in a Kawai-type double-stage multi-anvil apparatus in conjunction with synchrotron X-radiation, thereby providing a convenient and reliable gauge for pressure determination at ambient and high temperatures. The pressures derived from this new travel time method are in excellent agreement with those from the fixed-point methods. Application of this new pressure gauge in an offline experiment revealed a remarkable agreement of the densities of coesite with those from the previous single crystal compression studies under hydrostatic conditions, thus providing strong validation for the current travel time pressure scale. The travel time approach not only can be used for continuous in-situ pressure determination at room temperature, high temperatures, during compression and decompression, but also bears a unique capability that none of the previous scales can deliver, i.e., simultaneous pressure and temperature determination with a high accuracy (±0.16 GPa in pressure and ±17 °C in temperature). Therefore, the new in-situ Al 2 O 3 pressure gauge is expected to enable new and expanded opportunities for offline laboratory studies of solid and liquid materials under high pressure and high temperature in multi-anvil apparatus.
    Print ISSN: 0021-8979
    Electronic ISSN: 1089-7550
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 35
    Publication Date: 2015-08-11
    Description: We report a novel method of determining the average Néel relaxation time and its temperature dependence by calculating derivatives of the measured time dependence of temperature for a frozen ferrofluid exposed to an alternating magnetic field. The ferrofluid, composed of dextran-coated Fe 3 O 4 nanoparticles (diameter 13.7 nm ± 4.7 nm), was synthesized via wet chemical precipitation and characterized by x-ray diffraction and transmission electron microscopy. An alternating magnetic field of constant amplitude ( H 0 = 20 kA/m) driven at frequencies of 171 kHz, 232 kHz, and 343 kHz was used to determine the temperature dependent magnetic energy absorption rate in the temperature range from 160 K to 210 K. We found that the specific absorption rate of the ferrofluid decreased monotonically with temperature over this range at the given frequencies. From these measured data, we determined the temperature dependence of the Néel relaxation time and estimate a room-temperature magnetocrystalline anisotropy constant of 40 kJ/m 3 , in agreement with previously published results.
    Print ISSN: 0021-8979
    Electronic ISSN: 1089-7550
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 36
    Publication Date: 2015-08-11
    Description: We propose a concurrent multiscale molecular dynamics for molecular systems in order to apply macroscale mechanical boundary conditions such as traction and average displacement for solid state materials, which is difficult to do in traditional molecular dynamics where boundary conditions are applied in terms of forces and displacements on selected particles. The multiscale model is systematically constructed in terms of multiscale structures of kinematics, force field, and dynamical equations. The idea is to extend the Anderson-Parrinello-Rahman molecular dynamics to the cases that have arbitrary finite domain and boundary, thus the model is capable of solving inhomogeneous, non-equilibrium problems. The macroscale stress loading on a representative volume element with periodic boundary condition is generalized to all kinds of macroscale mechanical boundary conditions. Unlike most multiscale techniques, our theory is aimed at understanding fundamental physics rather than achieving computing efficiency. Examples of problems with prescribed average displacements and surface tractions are presented to demonstrate the validity of the proposed multiscale molecular dynamics.
    Print ISSN: 0021-9606
    Electronic ISSN: 1089-7690
    Topics: Chemistry and Pharmacology , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 37
    Publication Date: 2015-08-11
    Description: We study the effect of chain rigidity on the behavior of semiflexible polymers in the vicinity of flat walls in a slit, and of surfactants at the liquid-liquid interface between immiscible liquids. Using molecular dynamics simulations, it is demonstrated that the impact of bending angle forces is particularly strong within the depletion layer at the phase boundary whereas at distance R e away from the interface, where R e is the mean distance between the ends of a semiflexible chain, the contribution of these non-local triplet interactions to pressure tensor virtually disappears. The present study also demonstrates that growing stiffness of the macromolecules leads to an increase in surface tension and total pressure.
    Print ISSN: 0021-9606
    Electronic ISSN: 1089-7690
    Topics: Chemistry and Pharmacology , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 38
    Publication Date: 2015-08-11
    Description: Quantum-chemical computations of nuclear quadrupole-coupling parameters for 24 open-shell states of small molecules based on non-relativistic and spin-free exact two-component (SFX2C) relativistic equation-of-motion coupled-cluster (EOM-CC) as well as spin-orbital-based restricted open-shell Hartree-Fock coupled-cluster (ROHF-CC) methods are reported. Relativistic effects, the performance of the EOM-CC and ROHF-CC methods for treating electron correlation, as well as basis-set convergence have been carefully analyzed. Consideration of relativistic effects is necessary for accurate calculations on systems containing third-row (K-Kr) and heavier elements, as expected, and the SFX2C approach is shown to be a useful cost-effective option here. Further, it is demonstrated that the EOM-CC methods constitute flexible and accurate alternatives to the ROHF-CC methods in the calculations of nuclear quadrupole-coupling parameters for open-shell states.
    Print ISSN: 0021-9606
    Electronic ISSN: 1089-7690
    Topics: Chemistry and Pharmacology , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 39
    Publication Date: 2015-08-11
    Description: We study the continuity of an abstract generalization of the maximum-entropy inference—a maximizer. It is defined as a right-inverse of a linear map restricted to a convex body which uniquely maximizes on each fiber of the linear map a continuous function on the convex body. Using convex geometry we prove, amongst others, the existence of discontinuities of the maximizer at limits of extremal points not being extremal points themselves and apply the result to quantum correlations. Further, we use numerical range methods in the case of quantum inference which refers to two observables. One result is a complete characterization of points of discontinuity for 3 × 3 matrices.
    Print ISSN: 0022-2488
    Electronic ISSN: 1089-7658
    Topics: Mathematics , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 40
    Publication Date: 2015-08-11
    Description: A quantum two-path interferometer allows for direct measurement of the transmission phase shift of an electron, providing useful information on coherent scattering problems. In mesoscopic systems, however, the two-path interference is easily smeared by contributions from other paths, and this makes it difficult to observe the true transmission phase shift. To eliminate this problem, multi-terminal Aharonov-Bohm (AB) interferometers have been used to derive the phase shift by assuming that the relative phase shift of the electrons between the two paths is simply obtained when a smooth shift of the AB oscillations is observed. Nevertheless, the phase shifts using such a criterion have sometimes been inconsistent with theory. On the other hand, we have used an AB ring contacted to tunnel-coupled wires and acquired the phase shift consistent with theory when the two output currents through the coupled wires oscillate with well-defined anti-phase. Here, we investigate thoroughly these two criteria used to ensure a reliable phase measurement, the anti-phase relation of the two output currents, and the smooth phase shift in the AB oscillation. We confirm that the well-defined anti-phase relation ensures a correct phase measurement with a quantum two-path interference. In contrast, we find that even in a situation where the anti-phase relation is less well-defined, the smooth phase shift in the AB oscillation can still occur but does not give the correct transmission phase due to contributions from multiple paths. This indicates that the phase relation of the two output currents in our interferometer gives a good criterion for the measurement of the true transmission phase, while the smooth phase shift in the AB oscillation itself does not.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 41
    Publication Date: 2015-08-11
    Description: The stability of a long scale equilibrium vortex structure to short scale perturbations is studied in a strongly coupled dusty plasma in the framework of a generalized hydrodynamic model. It is shown that the free energy associated with the velocity shear of the vortex can drive secondary instabilities consisting of transverse shear waves when the resonance condition between the vortex rotation frequency and the secondary wave frequency is met. Such a process can transfer energy from the long scale vortex to the short scale secondary wave and thereby provide a saturation mechanism for long scale vortices in plasmas in a manner analogous to that in neutral fluids.
    Print ISSN: 1070-664X
    Electronic ISSN: 1089-7674
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 42
    Publication Date: 2015-08-11
    Description: A laser produced high-Z plasma in which an energy balance is achieved due to radiation emission and radiative heat transfer supports ion acoustic instability. A linear dispersion relation is derived, and instability is compared to the radiation cooling instability [R. G. Evans, Plasma Phys. Controlled Fusion 27 , 751 (1985)]. Under conditions of indirect drive fusion experiments, the driving term for the instability is the radiative heat flux and, in particular, the density dependence of the radiative heat conductivity. A specific example of thermal Bremsstrahlung radiation source has been considered. This instability may lead to plasma jet formation and anisotropic x-ray generation, thus affecting inertial confinement fusion related experiments.
    Print ISSN: 1070-664X
    Electronic ISSN: 1089-7674
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 43
    Publication Date: 2015-08-11
    Description: The present paper is devoted to simulation of nonlinear disintegration of a localized perturbation into ion-acoustic solitons train in a plasma with hot electrons and cold ions. A Gaussian initial perturbation is used to model the localized perturbation. For this purpose, first, we reduce fluid system of equations to a Korteweg de-Vries equation by the following well-known assumptions. (i) On the ion-acoustic evolution time-scale, the electron velocity distribution function (EVDF) is assumed to be stationary. (ii) The calculation is restricted to small amplitude cases. Next, in order to generalize the model to finite amplitudes cases, the evolution of EVDF is included. To this end, a hybrid code is designed to simulate the case, in which electrons dynamics is governed by Vlasov equation, while cold ions dynamics is, like before, studied by the fluid equations. A comparison between the two models shows that although the fluid model is capable of demonstrating the general features of the process, to have a better insight into the relevant physics resulting from the evolution of EVDF, the use of kinetic treatment is of great importance.
    Print ISSN: 1070-664X
    Electronic ISSN: 1089-7674
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 44
    Publication Date: 2015-08-11
    Description: Coherence oscillations measured in two-dimensional (2D) electronic spectra of pigment-protein complexes may have electronic, vibrational, or mixed-character vibronic origins, which depend on the degree of electronic-vibrational mixing. Oscillations from intrapigment vibrations can obscure the inter-site coherence lifetime of interest in elucidating the mechanisms of energy transfer in photosynthetic light-harvesting. Huang-Rhys factors ( S ) for low-frequency vibrations in Chlorophyll and Bacteriochlorophyll are quite small ( S ≤ 0.05), so it is often assumed that these vibrations influence neither 2D spectra nor inter-site coherence dynamics. In this work, we explore the influence of S within this range on the oscillatory signatures in simulated 2D spectra of a pigment heterodimer. To visualize the inter-site coherence dynamics underlying the 2D spectra, we introduce a formalism which we call the “site-probe response.” By comparing the calculated 2D spectra with the site-probe response, we show that an on-resonance vibration with Huang-Rhys factor as small as S = 0.005 and the most strongly coupled off-resonance vibrations ( S = 0.05) give rise to long-lived, purely vibrational coherences at 77 K. We moreover calculate the correlation between optical pump interactions and subsequent entanglement between sites, as measured by the concurrence. At 77 K, greater long-lived inter-site coherence and entanglement appear with increasing S . This dependence all but vanishes at physiological temperature, as environmentally induced fluctuations destroy the vibronic mixing.
    Electronic ISSN: 1931-9223
    Topics: Chemistry and Pharmacology , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 45
    Publication Date: 2015-08-11
    Description: We demonstrate high precision controllability of the magnetization reversal nucleation process in [Co/Pd] 8 multilayer films consisting of two sets of bilayers with high and low perpendicular anisotropy, respectively. The anisotropy of the entire film is set by the degree of Co/Pd interfacial mixing during deposition which provides fine control of the anisotropy of an individual bilayer in the multilayer stack. The relative number of each type of bilayer is used to select the magnetisation reversal behavior such that changing one bilayer changes the properties of the entire multilayer through anisotropy averaging. A simple extension to the sputtering protocol would provide multilayer films with fully graded anisotropy, while maintaining a constant saturation magnetization opening new possibilities for the creation of highly engineered multilayer structures for spin torque devices and future magnetic recording media.
    Print ISSN: 0021-8979
    Electronic ISSN: 1089-7550
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 46
    Publication Date: 2015-08-11
    Description: Coherence oscillations measured in two-dimensional (2D) electronic spectra of pigment-protein complexes may have electronic, vibrational, or mixed-character vibronic origins, which depend on the degree of electronic-vibrational mixing. Oscillations from intrapigment vibrations can obscure the inter-site coherence lifetime of interest in elucidating the mechanisms of energy transfer in photosynthetic light-harvesting. Huang-Rhys factors ( S ) for low-frequency vibrations in Chlorophyll and Bacteriochlorophyll are quite small ( S ≤ 0.05), so it is often assumed that these vibrations influence neither 2D spectra nor inter-site coherence dynamics. In this work, we explore the influence of S within this range on the oscillatory signatures in simulated 2D spectra of a pigment heterodimer. To visualize the inter-site coherence dynamics underlying the 2D spectra, we introduce a formalism which we call the “site-probe response.” By comparing the calculated 2D spectra with the site-probe response, we show that an on-resonance vibration with Huang-Rhys factor as small as S = 0.005 and the most strongly coupled off-resonance vibrations ( S = 0.05) give rise to long-lived, purely vibrational coherences at 77 K. We moreover calculate the correlation between optical pump interactions and subsequent entanglement between sites, as measured by the concurrence. At 77 K, greater long-lived inter-site coherence and entanglement appear with increasing S . This dependence all but vanishes at physiological temperature, as environmentally induced fluctuations destroy the vibronic mixing.
    Print ISSN: 0021-9606
    Electronic ISSN: 1089-7690
    Topics: Chemistry and Pharmacology , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 47
    Publication Date: 2015-08-11
    Description: Electrochemical in operando X-ray diffraction (XRD) is a powerful method to analyze structural changes of energy storage materials while inserting/de-inserting charge carriers, such as Li- or Na-ions, into/from a host structure. The design of an XRD in operando cell is presented, which enables the use of thin (6 μ m) aluminum foil as X-ray window as a non-toxic alternative to conventional beryllium windows. Owing to the reduced thickness, diffraction patterns and their changes during cycling can be observed with excellent quality, which was demonstrated for two cathode materials for sodium-ion batteries in a half-cell set-up, P2-Na 0.7 MnO 2 and Na 2.55 V 6 O 16 ⋅ 0.6H 2 O.
    Print ISSN: 0034-6748
    Electronic ISSN: 1089-7623
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 48
    Publication Date: 2015-08-12
    Description: We present a method for noninvasively imaging the hand joints using a three-dimensional (3D) photoacoustic imaging (PAI) system. This 3D PAI system utilizes cylindrical scanning in data collection and virtual-detector concept in image reconstruction. The maximum lateral and axial resolutions of the PAI system are 70  μ m and 240  μ m. The cross-sectional photoacoustic images of a healthy joint clearly exhibited major internal structures including phalanx and tendons, which are not available from the current photoacoustic imaging methods. The in vivo PAI results obtained are comparable with the corresponding 3.0 T MRI images of the finger joint. This study suggests that the proposed method has the potential to be used in early detection of joint diseases such as osteoarthritis.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 49
    Publication Date: 2015-08-12
    Description: We show how to levitate a liquid droplet above a plasma. Submitting a conductive droplet to a voltage larger than 50 V, we get a levitation regime that looks like the one obtained with the well-known thermal Leidenfrost effect, except that light is emitted from beneath the droplet. Spectroscopic analysis shows that this light is emitted by a cold and dense plasma and also that lines coming from the cathode plate material are present revealing a local cathodic sputtering effect. We examine the conditions for the levitation to occur and show that the levitation is essentially of thermal origin. Assuming a stationary heat transfer, we present a model that accounts well for the observed levitation conditions. In particular, stable levitation is shown to be possible for thin cathode plates only.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 50
    Publication Date: 2015-08-12
    Description: We have performed atomistic simulations of the phonon-limited high field carrier transport in ⟨ 110 ⟩ Si nanowires with small diameter. The carrier drift velocities are obtained from a direct solution of the non-linear Boltzmann transport equation. The relationship between the drift velocity and the electric field considerably depends on the carrier, temperature, and diameter of the nanowires. In particular, the threshold between the linear and non-linear regimes exhibits important variations. The drift velocity reaches a maximum value and then drops. These trends can be related to the effects of quantum confinement on the band structure of the nanowires. We also discuss the impact of the different phonon modes and show that high-energy phonons can, unexpectedly, increase the drift velocity at a high electric field.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 51
    Publication Date: 2015-08-12
    Description: Ion implantation is proposed to produce self-standing bent monocrystals. A Si sample 0.2 mm thick was bent to a radius of curvature of 10.5 m. The sample curvature was characterized by interferometric measurements; the crystalline quality of the bulk was tested by X-ray diffraction in transmission geometry through synchrotron light at ESRF (Grenoble, France). Dislocations induced by ion implantation affect only a very superficial layer of the sample, namely, the damaged region is confined in a layer 1  μ m thick. Finally, an elective application of a deformed crystal through ion implantation is here proposed, i.e., the realization of a crystalline undulator to produce X-ray beams.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 52
    Publication Date: 2015-08-12
    Description: One-dimensional (1D) nanotubes of Nd 0.1 Bi 0.9 FeO 3 (NBFO) with an inner diameter of ∼50 nm were synthesized via sol-gel based electrospinning without template assistant. The phases, morphologies, crystalline structures, and magnetic properties of these 1D nanostructures were characterized by means of X-ray diffraction, scanning electron microscopy, transmission electron microscopy and SQUID, respectively. It was found that the calcination condition plays a crucial role in determining the morphologies and the magnetic properties. Interestingly, these 1D NBFO nanotubes exhibit wasp-waisted magnetic hysteresis with a lower coercivity and larger saturation magnetization, which were prevalent in natural rocks and artificial composite materials. The origin of these wasp-waisted hysteresis loops was discussed.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 53
    Publication Date: 2015-08-12
    Description: Atmospheric pressure pulsed helium plasma jets are utilized for plasma-cell interactions. The effect of operating parameters such as applied voltage, pulse repetition frequency, and duty ratio on the generation of specific reactive oxygen and nitrogen species in gas and liquid phases and within cells is investigated. The apoptotic changes detected by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling assay in cells caused by plasma exposure are observed to correlate well with the levels of extracellular and intracellular reactive oxygen and nitrogen species.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 54
    Publication Date: 2015-08-12
    Description: We report photovoltaic response of highly transparent graphene/BiFe 0.95 Si 0.05 O 3 (BFSiO)/ITO/glass derived from bottom-up spin coating technique. The device exhibits short-circuit-current (I SC 0.75 mA) with 1000 fold upsurge and open-circuit-voltage (V OC  ∼ 0.45 V) under standard AM 1.5 illumination through graphene. In combination, I SC of 0.63 mA and V OC of 0.35 V for same illumination through ITO, reveals the prospects of harvesting indoor light. Also, crystallographic structure, red shift in band gap, leakage behavior, and ferroelectric characteristics of BFSiO thin films are reported. Reproducible transient response of I SC and V OC with quick switching (
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 55
    Publication Date: 2015-08-12
    Description: Physical insights on the hydrodynamics and locomotion of self-propelled nanowire motor under nonequilibrium steady state are investigated using finite element method in accordance with hybrid molecular dynamics/multiparticle collision dynamics and rigid body dynamics. Nanowire motor is discretized into finite segments, and forces of solvent molecule acting on the motor are assumed to be the sum of forces acting on all segments of the motor. We show that the locomotion of nanowire motor is mainly determined by the imbalance forces acting on the catalytic and noncatalytic segments. The average velocity along the axis increases significantly as a function of time prior to reaching equilibrium. The length of nanowire motor shows negligible effect on the velocity of the motor. Preliminary experimental results are provided to validate the current model.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 56
    Publication Date: 2015-08-12
    Description: Ultrahigh density periodically ordered magnetic yttrium iron garnet (Y 3 Fe 5 O 12 , YIG) nanodot arrays have been prepared by pulsed laser deposition through an ultrathin alumina mask (UTAM). UTAM having periodically ordered circularly shaped holes with 350 nm in diameter, 450 nm in inter-pore distance, and 700 nm in height has been prepared on silicon substrate. Furthermore, the microstructure and magnetic properties of YIG nanodot arrays have been characterized. Nanodot arrays with a sharp distribution in diameter centered at 340 nm with standard deviation of 10 nm have been fabricated. Moreover, typical hysteresis loops and ferromagnetic resonance spectra in in-plane and out-of-plane revealed that this unique structure greatly influences the magnetics properties of YIG. First, coercivity of YIG nanodot arrays in in-plane was increased about from 15 Oe of YIG films to 500 Oe. Then, the degree of uniformity about nanodot height decided that two or more resonance peaks in out-of-plane were detected in the spectra. The peak-to-peak linewidth values were about 94 Oe and 40 Oe in the parallel and perpendicular directions, respectively, which indicated that the values were larger by the two-magnon scattering. Consequently, this pattering method creates opportunities for studying physics in oxide nanomagnets and may be applied in spin-wave devices.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 57
    Publication Date: 2015-08-12
    Description: We report on the tuning of the optical properties of II-VI-material-based microcavity samples, which is achieved by depositing Ag films on top of the structures. The micro-reflectivity spectra show a spectral shift of the sample resonance dependent on the metal layer thickness. By comparison of the experimental findings with the theoretical calculations applying the transfer matrix method on a metal-dielectric mirror structure, the influence of the metal layer particularly with regard to its partial oxidation was explored. Tamm plasmon modes are created at the interface between an open cavity with three ZnSe quantum wells and a metal layer on top. When tuning the excitonic emission relative to the mode by changing the sample temperature, an anticrossing of the resonances was observed. This is a clear indication that the strong coupling regime has been achieved in that sample configuration yielding a Rabi splitting of 18.5 meV. These results are promising for the realization of polariton-based optical devices with a rather simple sample configuration.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 58
    Publication Date: 2015-08-12
    Description: As urbanization continues across the globe, cities face significant challenges and opportunities to grow in ways that reduce carbon emissions while providing high quality of life. An EcoPartnership between the cities of Portland, Oregon, USA and Kunming, China is designed to accelerate the exchange of policies and strategies for low-carbon development. Kunming successfully implemented China's first bus-rapid transit system (BRT); Portland is currently analyzing the feasibility of BRT. Portland relies on an urban growth boundary (UGB) as a key policy to guide growth management; Kunming is evaluating the feasibility of a UGB. Both cities are investing in infrastructure for bicycle networks. Key characteristics of successful collaboration include shared substantive priorities; familiarity with the institutional context and roles of the individuals involved; a good match in the responsibilities of the participating agencies and individuals; interpersonal rapport and trust; and the persistence of the collaboration over time.
    Electronic ISSN: 1941-7012
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 59
    Publication Date: 2015-08-12
    Description: The duplication-divergence network model is generally thought to incorporate key ingredients underlying the growth and evolution of protein-protein interaction networks. Properties of the model have been elucidated through numerous simulation studies. However, a comprehensive theoretical study of the model is lacking. Here, we derived analytic expressions for quantities describing key characteristics of the network—the average degree, the degree distribution, the clustering coefficient, and the neighbor connectivity—in the mean-field, large- N limit of an extended version of the model, duplication-divergence complemented with heterodimerization and addition. We carried out extensive simulations and verified excellent agreement between simulation and theory except for one partial case. All four quantities obeyed power-laws even at moderate network size ( N ∼ 10 4 ), except the degree distribution, which had an additional exponential factor observed to obey power-law. It is shown that our network model can lead to the emergence of scale-free property and hierarchical modularity simultaneously, reproducing the important topological properties of real protein-protein interaction networks.
    Print ISSN: 1054-1500
    Electronic ISSN: 1089-7682
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 60
    Publication Date: 2015-08-12
    Description: The effect of filler aspect ratio on the electromagnetic properties of epoxy-amine resin reinforced with carbon nanofibers is here investigated. A heat treatment at 2500 °C of carbon nanofibers seems to increase their aspect ratio with respect to as-received ones most likely due to a lowering of structural defects and the improvement of the graphene layers within the dixie cup conformation. These morphological differences revealed by Raman's spectroscopy and scanning electron microscopy analyses may be responsible for the different electrical properties of the resulting composites. The DC characterization of the nanofilled material highlights an higher electrical conductivity and a lower electrical percolation threshold for the heat-treated carbon nanofibers based composites. In fact, the electrical conductivity is about 0.107 S/m and 1.36 × 10 −3  S/m for the nanocomposites reinforced with heat-treated and as received fibers, respectively, at 1 wt. % of nanofiller loading, while the electrical percolation threshold falls in the range [0.05–0.32]wt. % for the first nanocomposites and above 0.64 wt. % for the latter. Moreover, also a different frequency response is observed since the critical frequency, which is indicative of the transition from a resistive to a capacitive-type behaviour, shifts forward of about one decade at the same filler loading. The experimental results are supported by theoretical and simulation studies focused on the role of the filler aspect ratio on the electrical properties of the nanocomposites.
    Print ISSN: 0021-8979
    Electronic ISSN: 1089-7550
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 61
    Publication Date: 2015-08-12
    Description: Analyses of the local crystal and electronic structure in the vicinity of Fe 3+ centers in perovskite KMgF 3 crystal have been carried out in a comprehensive manner. A combination of density functional theory (DFT) and a semi-empirical superposition model (SPM) is used for a complete analysis of all Fe 3+ centers in this study for the first time. Some quantitative information has been derived from the DFT calculations on both the electronic structure and the local geometry around Fe 3+ centers. All of the trigonal (K-vacancy case, K-Li substitution case, and normal trigonal Fe 3+ center case), FeF 5 O cluster, and tetragonal (Mg-vacancy and Mg-Li substitution cases) centers have been taken into account based on the previously suggested experimental and theoretical inferences. The collaboration between the experimental data and the results of both DFT and SPM calculations provides us to understand most probable structural model for Fe 3+ centers in KMgF 3 .
    Print ISSN: 0021-8979
    Electronic ISSN: 1089-7550
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 62
    Publication Date: 2015-08-12
    Print ISSN: 0021-9606
    Electronic ISSN: 1089-7690
    Topics: Chemistry and Pharmacology , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 63
    Publication Date: 2015-08-12
    Description: Potassium 1,1′-dinitroamino-5,5′-bistetrazolate (K 2 DNABT) is a nitrogen rich (50.3% by weight, K 2 C 2 N 12 O 4 ) green primary explosive with high performance characteristics, namely, velocity of detonation (D = 8.33 km/s), detonation pressure (P = 31.7 GPa), and fast initiating power to replace existing toxic primaries. In the present work, we report density functional theory (DFT) calculations on structural, equation of state, vibrational spectra, electronic structure, and absorption spectra of K 2 DNABT. We have discussed the influence of weak dispersive interactions on structural and vibrational properties through the DFT-D2 method. We find anisotropic compressibility behavior (b
    Print ISSN: 0021-9606
    Electronic ISSN: 1089-7690
    Topics: Chemistry and Pharmacology , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 64
    Publication Date: 2015-08-12
    Description: We perform direct large molecular dynamics simulations of homogeneous SPC/E water nucleation, using up to ∼ 4 ⋅ 10 6 molecules. Our large system sizes allow us to measure extremely low and accurate nucleation rates, down to ∼ 10 19  cm −3 s −1 , helping close the gap between experimentally measured rates ∼ 10 17  cm −3 s −1 . We are also able to precisely measure size distributions, sticking efficiencies, cluster temperatures, and cluster internal densities. We introduce a new functional form to implement the Yasuoka-Matsumoto nucleation rate measurement technique (threshold method). Comparison to nucleation models shows that classical nucleation theory over-estimates nucleation rates by a few orders of magnitude. The semi-phenomenological nucleation model does better, under-predicting rates by at worst a factor of 24. Unlike what has been observed in Lennard-Jones simulations, post-critical clusters have temperatures consistent with the run average temperature. Also, we observe that post-critical clusters have densities very slightly higher, ∼ 5%, than bulk liquid. We re-calibrate a Hale-type J vs. S scaling relation using both experimental and simulation data, finding remarkable consistency in over 30 orders of magnitude in the nucleation rate range and 180 K in the temperature range.
    Print ISSN: 0021-9606
    Electronic ISSN: 1089-7690
    Topics: Chemistry and Pharmacology , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 65
    Publication Date: 2015-08-12
    Description: Tensor factorization of the 2-electron integral matrix is a well-known technique for reducing the computational scaling of ab initio electronic structure methods toward that of Hartree-Fock and density functional theories. The simplest factorization that maintains the positive semidefinite character of the 2-electron integral matrix is the Cholesky factorization. In this paper, we introduce a family of positive semidefinite factorizations that generalize the Cholesky factorization. Using an implementation of the factorization within the parametric 2-RDM method [D. A. Mazziotti, Phys. Rev. Lett. 101 , 253002 (2008)], we study several inorganic molecules, alkane chains, and potential energy curves and find that this generalized factorization retains the accuracy and size extensivity of the Cholesky factorization, even in the presence of multi-reference correlation. The generalized family of positive semidefinite factorizations has potential applications to low-scaling ab initio electronic structure methods that treat electron correlation with a computational cost approaching that of the Hartree-Fock method or density functional theory.
    Print ISSN: 0021-9606
    Electronic ISSN: 1089-7690
    Topics: Chemistry and Pharmacology , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 66
    Publication Date: 2015-08-13
    Description: Triple Langmuir Probe (TLP) is a widely used diagnostics for instantaneous measurement of electron temperature and density in low temperature laboratory plasmas as well as in edge region of fusion plasma devices. Presence of a moderately energetic flowing electron component, constituting only a small fraction of the bulk electrons, is also a generally observed scenario in plasma devices, where plasmas are produced by electron impact ionization of neutrals. A theoretical analysis of its effect on interpretation of the TLP data for bulk electron temperature measurement is presented here assuming electron velocity distribution is not deviating substantially from a Maxwellian. The study predicts conventional expression from standard TLP theory to give overestimated value of bulk electron temperature. Correction factor is significant and largely depends on population density, temperature, and energy of the fast component. Experimental verification of theoretical results is obtained in the magnetized plasma linear experimental device of Saha Institute of Nuclear Physics where plasma is produced by an electron cyclotron resonance method and known to have a fast flowing electron component.
    Print ISSN: 0021-8979
    Electronic ISSN: 1089-7550
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 67
    Publication Date: 2015-08-13
    Description: The recent energy demands affected by the dilution of conventional energy resources and the growing awareness of environmental considerations had motivated many researchers to seek for novel renewable energy conversion methods. Thermoelectric direct conversion of thermal into electrical energies is such a method, in which common compositions include IV-VI semiconducting compounds (e.g., PbTe and SnTe) and their alloys. For approaching practical thermoelectric devices, the current research is focused on electronic optimization of off-stoichiometric p -type Pb x Sn 1− x Te alloys by tuning of Bi 2 Te 3 doping and/or SnTe alloying levels, while avoiding the less mechanically favorable Na dopant. It was shown that upon such doping/alloying, higher ZT s, compared to those of previously reported undoped Pb 0.5 Sn 0.5 Te alloy, were obtained at temperatures lower than 210–340 °C, depending of the exact doping/alloying level. It was demonstrated that upon optimal grading of the carrier concentration, a maximal thermoelectric efficiency enhancement of ∼38%, compared to that of an undoped material, is expected.
    Print ISSN: 0021-8979
    Electronic ISSN: 1089-7550
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 68
    Publication Date: 2015-08-13
    Description: The properties of one-dimensional (1D) nanostructured materials can change considerably and unexpectedly, when their diameters attain the “ultrathin” level, i.e., below 10 nm. Herein, we have summarized recent developments associated with not only the synthesis but also more importantly, the applications of ultrathin 1D nanowires. Specifically, various classes of ultrathin metallic nanowires have been shown to be excellent, high-performing structural motifs for electrocatalysts, superconducting materials, electrical devices, and nano-sized pressure sensors. Moreover, the fabrication of ultrathin-based 0D-1D, 1D-1D, and 1D-2D composite hybrid structures may represent one of the most promising designs for novel architectures in energy storage and conversion, photovoltaic devices, photoconductivity, and photoelectrocatalysis.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 69
    Publication Date: 2015-08-13
    Description: One of the grand challenges facing materials-by-design approaches for complex oxide deployment in electronic devices is how to balance transformative first-principles based predictions with experimental feasibility. Here, we briefly review the functionality-driven approach (inverse design) for materials discovery, encapsulated in three modalities for materials discovery ( m 3 D) that integrate experimental feedback. We compare it to both traditional theoretical and high-throughput database-directed approaches aimed at advancing oxide-based materials into technologies.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 70
    Publication Date: 2015-08-13
    Description: Double cathode buffer layers (CBLs) composed of fullerene derivative functionalized with a crown-ether end group in its side chain (denoted as PCBC) and a LiF layer were introduced between the PCBM acceptor layer and the top cathode in planar p-i-n perovskite solar cells (pero-SCs) based on CH 3 NH 3 PbI 3−X Cl X . The devices with the PCBC/LiF double CBLs showed significant improvements in power conversion efficiency (PCE) and long-term stability when compared to the device with LiF single CBL. Through optimizing the spin-coating speed of PCBC, a maximum PCE of 15.53% has been achieved, which is approximately 15% higher than that of the device with single LiF CBL. The remarkable improvement in PCE can be attributed to the formation of a better ohmic contact in the CBL between PCBC and LiF/Al electrode arising from the dipole moment of PCBC, leading to the enhanced fill factor and short-circuit current density ( J sc ). Besides the PCE, the long-term stability of the devices with PCBC interlayer is also superior to that of the device with LiF single CBL, which is due to the more effective protection for the perovskite/PCBM interface.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 71
    Publication Date: 2015-08-13
    Description: Using a combination of continuous wave and time-resolved spectroscopy, we study the effects of interfacial conditions on the radiative lifetimes and photoluminescence intensities of sub-monolayer colloidal CdTe/CdS quantum dots (QDs) embedded in a three-dimensional porous silicon (PSi) scaffold. The PSi matrix was thermally oxidized under different conditions to change the interfacial oxide thickness. QDs embedded in a PSi matrix with ∼0.4 nm of interfacial oxide exhibited reduced photoluminescence intensity and nearly five times shorter radiative lifetimes (∼16 ns) compared to QDs immobilized within completely oxidized, porous silica (PSiO 2 ) frameworks (∼78 ns). The exponential dependence of QD lifetime on interfacial oxide thickness in the PSi scaffolds suggests charge transfer plays an important role in the exciton dynamics.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 72
    Publication Date: 2015-08-13
    Description: Schottky Barrier-MOSFET technology offers intriguing possibilities for cryogenic nano-scale devices, such as Si quantum devices and superconducting devices. We present experimental results on a device architecture where the gate electrode is self-aligned with the device channel and overlaps the source and drain electrodes. This facilitates a sub-5 nm gap between the source/drain and channel, and no spacers are required. At cryogenic temperatures, such devices function as p-MOS Tunnel FETs, as determined by the Schottky barrier at the Al-Si interface, and as a further advantage, fabrication processes are compatible with both CMOS and superconducting logic technology.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 73
    Publication Date: 2015-08-13
    Description: We report an experimental study of the domain structure of ferroelectric YMnO 3 and YMn 0.9 Fe 0.1 O 3 using polycrystalline samples prepared by direct hydrothermal crystallisation at 240 °C, well below their structural phase transition temperatures. Powder X-ray diffraction shows the expected P 6 3 cm space group for both samples with an increase in a and a small decrease in c with Fe incorporation, consistent with an adjustment of MnO 5 tilting, while XANES spectra at the Mn and Fe K edges show the oxidation state of both metals are maintained at +3 in the doped sample. High resolution TEM shows that curved stripe, annular and vortex domains can all be observed in the YMnO 3 crystals, proving that the structural phase transition is not the only driving force for the occurrence of the annular and vortex domains. Furthermore, the absence of the annular and vortex domains in YMn 0.9 Fe 0.1 O 3 indicates that the tilting state of MnO 5 bipyramids plays an important role in the domain formation. Atomic resolution STEM images confirm that the ferroelectric domain walls correspond to structural antiphase boundaries similar to the crystals made via high temperature solid-state reactions.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 74
    Publication Date: 2015-08-13
    Description: An infrared detector is proposed that is based on a ferroelectric tunnel junction (FTJ) working under bolometer-like principles. Electron tunneling, either direct or indirect, through the ferroelectric barrier depends on the temperature of the devices. During tunneling, infrared radiation alters the polarization of the ferroelectric film via pyroelectricity, resulting in a change in the barrier height of the tunnel junction. A high temperature coefficient of resistance of up to −3.86% was observed at room temperature. These results show that the FTJ structure has potential to be adapted for use in uncooled infrared detectors.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 75
    Publication Date: 2015-08-13
    Description: Although magnetic heterostructures are the basis of many magnetic technologies, the mechanisms involved in magnetization reversals in such structures are not fully understood, especially in amorphous multilayers. Here, we report on the SmCo/CoAlZr system and exploit resonant magnetic x-ray scattering to probe the element specific magnetization reversals. When combined into a tri-layer structure, two different switching fields and reversal mechanisms are observed for the Sm and Co sub-lattices. We argue that the decoupling of the sub-lattices arises from the local distribution of atomic species within the amorphous matrix leading to a strong magnetic leverage effect and exchange pinning. The decoupling arises due to strong interactions between regions of high Co density which span the interface. The relatively sparse interactions between Sm and Co induce a localized pinning of the Co-rich areas, resulting in an exchange bias in minor loops and an enhanced coercivity.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 76
    Publication Date: 2015-08-13
    Description: The room-temperature ferromagnetic behavior of MnAs/GaAs(001) thin film has been locally explored by Transmission Electron Microscope (TEM). We first differentiated hexagonal α-MnAs and quasi-hexagonal β-MnAs which are very similar in atomic structure by electron diffraction. Local magnetic moment information of the identified α-MnAs was extracted from manganese-L 2,3 edges using Energy-loss Magnetic Circular Dichroism technique and the ratio of orbital to spin magnetic moment was measured. In this experiment, atomic structure identification, chemical analysis, and magnetic moment measurement were simultaneously achieved at high spatial resolution in TEM, thus providing a potential method for in-situ study of local properties of multiphase magnetic materials.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 77
    Publication Date: 2015-08-13
    Description: Ag 9 (SiO 4 ) 2 NO 3 was prepared by a reactive flux method. The structures, morphologies, and light absorption properties were investigated. Owing to the polar crystal structure, an internal electric field can be formed inside the material, which can facilitate the photogenerated charge separation during the photocatalytic process. Based on both the wide light absorption spectra and high charge separation efficiency originated from the polarized internal electric field, Ag 9 (SiO 4 ) 2 NO 3 exhibit higher efficiency over Ag 3 PO 4 during the degradation of organic dyes under visible light irradiation, which is expected to be a potential material for solar energy harvest and conversion.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 78
    Publication Date: 2015-08-13
    Description: We obtained photovoltaic response in pristine multilayer WSe 2 by sandwiching WSe 2 between top and bottom metals. In this structure, the work-function difference between the top metal and WSe 2 plays a critical role in generating built-in potentials and photovoltaic responses. Our devices with Zn as top metal exhibit photo-conversion efficiencies up to 6.7% under 532 nm illumination and external quantum efficiencies in the range of 40%–83% for visible light. This work provides a method for generating photovoltaic responses in layered semiconductors without detrimental doping or exquisite heterostructures, and also advances the physics for modulating the band structures of such emerging semiconductors.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 79
    Publication Date: 2015-08-13
    Description: We use cyclotron resonance THz-spectroscopy in pulsed magnetic fields up to 63 T to measure the electron effective mass in Si-doped GaAsN semiconductor alloys with nitrogen content up to 0.2%. This technique directly probes the transport properties of the N-modified conduction band, particularly the electron effective mass, which has been discussed controversially in the experimental and theoretical literature. We report a slight increase of the electron effective mass and nonparabolicity with N-content for different photon energies in agreement with the two-level band anticrossing model calculations. Furthermore, we show a pronounced electron mobility drop with increasing N-content.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 80
    Publication Date: 2015-08-13
    Description: Blending the conjugated polymer poly(3-hexylthiophene) (P3HT) with the insulating electret polystyrene (PS), we show that the threshold voltage V t of organic field-effect transistors (OFETs) can be easily and reversely tuned by applying a gate bias stress at 130 °C. It is proposed that this phenomenon is caused by thermally activated charge injection from P3HT into PS matrix, and that this charge is immobilized within the PS matrix after cooling down to room temperature. Therefore, room-temperature hysteresis-free FETs with desired V t can be easily achieved. The approach is applied to reversely tune the OFET mode of operation from accumulation to depletion, and to build inverters.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 81
    Publication Date: 2015-08-13
    Description: Reflective surfaces are one of the key elements of solar plants to concentrate energy in the receivers of solar thermal electricity plants. Polymeric substrates are being considered as an alternative to the widely used glass mirrors due to their intrinsic and processing advantages, but optimizing both the reflectance and the physical stability of polymeric mirrors still poses technological difficulties. In this work, polymeric surfaces have been functionalized with ceramic thin-films by atomic layer deposition. The characterization and optimization of the parameters involved in the process resulted in surfaces with a reflection index of 97%, turning polymers into a real alternative to glass substrates. The solution we present here can be easily applied in further technological areas where seemingly incompatible combinations of polymeric substrates and ceramic coatings occur.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 82
    Publication Date: 2015-08-13
    Description: Understanding the coupling of different modal frequencies and their tuning mechanisms has become essential to design multi-frequency MEMS devices. In this work, we fabricate a MEMS beam with fixed boundaries separated from two side electrodes and a bottom electrode. Subsequently, we perform experiments to obtain the frequency variation of in-plane and out-of-plane mechanical modes of the microbeam with respect to both DC bias and laser heating. We show that the frequencies of the two modes coincide at a certain DC bias, which in turn can also be varied due to temperature. Subsequently, we develop a theoretical model to predict the variation of the two modes and their coupling due to a variable gap between the microbeam and electrodes, initial tension, and fringing field coefficients. Finally, we discuss the influence of frequency tuning parameters in arrays of 3, 33, and 40 microbeams, respectively. It is also found that the frequency bandwidth of a microbeam array can be increased to as high as 25 kHz for a 40 microbeam array with a DC bias of 80 V.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 83
    Publication Date: 2015-08-13
    Description: Atomic-scale knowledge and control of oxidation of GaSb(100), which is a potential interface for energy-efficient transistors, are still incomplete, largely due to an amorphous structure of GaSb(100) oxides. We elucidate these issues with scanning-tunneling microscopy and spectroscopy. The unveiled oxidation-induced building blocks cause defect states above Fermi level around the conduction-band edge. By interconnecting the results to previous photoemission findings, we suggest that the oxidation starts with substituting second-layer Sb sites by oxygen. Adding small amount of indium on GaSb(100), resulting in a (4 × 2)-In reconstruction, before oxidation produces a previously unreported, crystalline oxidized layer of (1 × 3)-O free of gap states.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 84
    Publication Date: 2015-08-13
    Description: A scanning transmission electron microscope equipped with a backscattered and secondary electron detector is shown capable to image graphene and hexagonal boron nitride monolayers. Secondary electron contrasts of the two lightest monolayer materials are clearly distinguished from the vacuum level. A signal difference between these two materials is attributed to electronic structure differences, which will influence the escape probabilities of the secondary electrons. Our results show that the secondary electron signal can be used to distinguish between the electronic structures of materials with atomic layer sensitivity, enhancing its applicability as a complementary signal in the analytical microscope.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 85
    Publication Date: 2015-08-13
    Description: Refractive index sensing plays a key role in various environmental and biological sensing applications. Here, a method is presented for measuring the absolute refractive index dispersion of liquids using an array of photonic crystal resonant reflectors of varying periods. It is shown that by covering the array with a sample liquid and measuring the resonance wavelength associated with transverse electric polarized quasi guided modes as a function of period, the refractive index dispersion of the liquid can be accurately obtained using an analytical expression. This method is compact, can perform measurements at arbitrary number of wavelengths, and requires only a minute sample volume. The ability to sense a material's dispersion profile offers an added dimension of information that may be of benefit to optofluidic lab-on-a-chip applications.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 86
    Publication Date: 2015-08-13
    Description: Brillouin microscopy is an emerging technique to yield high spatial resolution mechanical images in a non-contact manner. The main challenge in Brillouin spectroscopy is given by the detection and the localisation of the Brillouin peaks, in particular, when a high amount of elastic light is collected. We demonstrate a purely interferometric method to suppress the parasitic light which overwhelms the Brillouin spectrum using destructive interference in a Michelson interferometer. A suppression ratio of 35 dB is readily achieved. Both double and single stage virtually imaged phased array spectrometers are tested showing that the Brillouin peaks can still be measured when the intensity of the elastic light is higher by 53 dB, hence, enabling 3D mechanical imaging of thin biological systems such as cells.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 87
    Publication Date: 2015-08-13
    Description: In earlier works, we used spheres of various sizes as impedance probes in demonstrating a method of determining plasma potential, φ p , when the probe radius is much larger than the Debye length, λ D . The basis of the method in those works [Walker et al ., Phys. Plasmas 13 , 032108 (2006); ibid . 15 , 123506 (2008); ibid . 17 , 113503 (2010)] relies on applying a small amplitude signal of fixed frequency to a probe in a plasma and, through network analyzer-based measurements, determining the complex reflection coefficient, Γ , for varying probe bias, V b . The frequency range of the applied signal is restricted to avoid sheath resonant effects and ion contributions such that ω pi  ≪ ω ≪ ω pe , where ω pi is the ion plasma frequency and ω pe is the electron plasma frequency. For a given frequency and applied bias, both Re( Z ac ) and Im( Z ac ) are available from Γ . When Re( Z ac ) is plotted versus V b , a minimum predicted by theory occurs at φ p [Walker et al ., Phys. Plasmas 17 , 113503 (2010)]. In addition, Im (Z ac ) appears at, or very near, a maximum at φ p . As n e decreases and the sheath expands, the minimum becomes harder to discern. The purpose of this work is to demonstrate that when using network analyzer-based measurements, Γ itself and Im (Z ac ) and their derivatives are useful as accompanying indicators to Re( Z ac ) in these difficult cases. We note the difficulties encountered by the most commonly used plasma diagnostic, the Langmuir probe. Spherical probe data is mainly used in this work, although we present limited data for a cylinder and a disk. To demonstrate the effect of lowered density as a function of probe geometry, we compare the cylinder and disk using only the indicator Re( Z ac ).
    Print ISSN: 1070-664X
    Electronic ISSN: 1089-7674
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 88
    Publication Date: 2015-08-13
    Description: The classical gravitational instability of a layer of denser fluid overlying a layer of less dense fluid, commonly known as the Rayleigh-Taylor instability, has been studied for well over a hundred years. In this article, we present the results of numerical simulations of a variant of this instability in which a plug of dense fluid is released from rest in a thin channel between two flat, vertical walls, causing a downward acceleration of the entire fluid column and formation of boundary layers near the walls. The plug of dense fluid undergoes distinctly different evolution near the walls and in the fluid interior. The instability in the interior, which we label the “hammerhead” instability based on its shape, is robust over a range of physical parameters, but disappears below a threshold Schmidt number. Fluid near the wall is slowed, and thin tendrils that link the near wall fluid to the main body of the fluid plug form, and in some cases undergo their own instability. We characterize the fully three-dimensionalized state, finding that while bulk measures of kinetic energy three-dimensionalization do not discriminate between low and high Schmidt number cases, the geometric distributions of the dynamical parameters Q and R from the turbulence literature are profoundly different in the high Schmidt number case. Finally, we consider the role of shear in situations in which the two plates are not exactly vertical, demonstrating that shear diminishes the importance of three-dimensionalization, while the hammerhead instability remains relevant.
    Print ISSN: 1070-6631
    Electronic ISSN: 1089-7666
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 89
    Publication Date: 2015-08-13
    Description: Flow past two cylinders of different diameters in close proximity is simulated numerically for a constant diameter ratio of 0.45, a gap ratio of 0.0625, and a Reynolds number of 1000 (defined using the diameter of the main cylinder). The effect of the position angle α of the small cylinder relative to the large one on force coefficients and wake flow patterns are studied. Depending on the position angle α of the small cylinder, four wake flow modes are identified: the upstream interference mode for α = 0°, 22.5°, and 45°, the intermittent attached gap flow mode for α = 67.5° and 90°, the attached gap flow mode for α = 112.5° and 135°, and the wake interference mode for α = 157.5° and 180°. The RMS lift coefficients of both cylinders are reduced significantly compared with that of a single cylinder, regardless of the position angle of the small cylinder. Although the variation trends of the mean drag and lift coefficients with the position angle of the small cylinder obtained from the two-dimensional (2D) and three-dimensional (3D) simulations are similar, the 2D simulations overestimate the mean drag coefficient, the RMS drag and lift coefficients compared with those obtained from the 3D simulations.
    Print ISSN: 1070-6631
    Electronic ISSN: 1089-7666
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 90
    Publication Date: 2015-08-13
    Print ISSN: 1070-664X
    Electronic ISSN: 1089-7674
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 91
    Publication Date: 2015-08-13
    Description: Farley-Buneman modes are an example of the collisional instability, which is thought to be the dominant mechanism for the irregularities in low ionosphere region. Despite high collisionality due to electron-neutral and ion-neutral collisions, the kinetic effects associated with finite temperature are important for determination of the mode frequencies and growth rate. This is especially important for ion component that is largely unmagnetized due to low ion cyclotron frequency. The ion thermal effects are strongly pronounced for shorter wavelengths and are crucial for the growth rate cut-off at high wavenumbers. We develop an extended fluid model for ion dynamics to incorporate the effects of ion thermal motion. The model is based on the extended MHD model that includes the evolution equations for higher order moments such as ion viscosity and ion heat flux. We also develop the generalized Chapman-Enskog closure model that provides exact linear closures based on the linearized kinetic equation. The results of these models are compared and tested against the linear kinetic model. The dispersion of Farley-Buneman modes and growth rate behavior are investigated in the short wavelength region.
    Print ISSN: 1070-664X
    Electronic ISSN: 1089-7674
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 92
    Publication Date: 2015-08-14
    Description: Ultrafast energy relaxation process in Bi 2 Te 3 thin films is studied using a collinear two color pump-probe technique. The coherent optical phonon is enhanced and destroyed by changing the separation times of double pump pulses. The non-oscillatory component of the reflectivity trace after the second pump pulse shows a distinct difference with and without the presence of coherent optical phonons, thus providing a direct evidence of the effect of optical phonon on the hot carrier relaxation process. The deduced characteristic times are systematically smaller when coherent optical phonons are involved in the energy transfer process. Comparatively, the conventional relaxation process is relatively slow, which is explained by the screening effect of the incoherent optical phonon. This work suggests that the energy relaxation can be manipulated through the excitation of coherent optical phonons.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 93
    Publication Date: 2015-08-14
    Description: Using first-principles calculations, we show that the conduction and valence band energies and their deformation potentials exhibit a non-negligible compositional bowing in strained ternary semiconductor alloys such as InGaAs. The electronic structure of these compounds has been calculated within the framework of local density approximation and hybrid functional approach for large cubic supercells and special quasi-random structures, which represent two kinds of model structures for random alloys. We find that the predicted bowing effect for the band energy deformation potentials is rather insensitive to the choice of the functional and alloy structural model. The direction of bowing is determined by In cations that give a stronger contribution to the formation of the In x Ga 1− x As valence band states with x ≳ 0.5, compared to Ga cations.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 94
    Publication Date: 2015-08-14
    Description: Magnetic, dielectric, and ac conductivity as well as room temperature structural and Raman studies are performed on double perovskite Dy 2 NiMnO 6 . The crystal structure of the compound adopts monoclinic P2 1 /n space group, where alternate Mn and Ni distorted octahedral are arranged in anti-phase a − a − b + order in Glazer notation. Magnetization studies show two magnetic transitions around 100 K and 20 K which are related to the ordering of transition and rare earth cations moment, respectively. Temperature dependent dielectric permittivity shows Havriliak-Negami type thermally activated dielectric relaxation. The ac conductivity at different temperature is found to follow Jonscher power law behavior. Time-temperature scaling of the conductivity spectra reveals that the charge transport dynamics is independent of temperature. Intriguingly, an anomaly in the dielectric constant is observed close to the order of Dy moment which indicates intrinsic magnetoelectric coupling. The hybridization between Dy and Ni/Mn is suggested to be correlated with the magnetoelectric coupling.
    Print ISSN: 0021-8979
    Electronic ISSN: 1089-7550
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 95
    Publication Date: 2015-08-14
    Description: The stable configurations and electronic and magnetic properties of nonmetal atoms (H, N, P, O, S, F, and Cl) adsorbed ReS 2 monolayers have been investigated by first-principles calculations. It is found that H, O, S, F, and Cl prefer to occupy the peak sites of S atoms, while both N and P atoms favor the valley sites of S atoms. The ReS 2 sheet exhibits a good adsorption capability to nonmetal atoms. The reconstruction of the surface is pronounced in N- and P-adsorbed ReS 2 monolayers. In H-adsorbed case, the Fermi level is pulled into the conduction band, which results in the semiconductor-metal transition. The same magnetic moment of 1 μ B is found in the N-, P-, F-, and Cl-adsorbed ReS 2 monolayers, while the mechanisms of forming magnetic moment for N (P)- and F (Cl)-adsorbed cases are different. In addition, the spatial extensions of spin density in P-, F-, and Cl-adsorbed cases are larger than that in N-adsorbed case, which is more suitable to achieve long-range magnetic coupling interaction at low defect concentrations. Our results provide insight for achieving metal-free magnetism and a tunable band gap for various electronic and spintronic devices based on ReS 2 .
    Print ISSN: 0021-8979
    Electronic ISSN: 1089-7550
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 96
    Publication Date: 2015-08-14
    Description: Three different chemical solutions are used to remove the possible contamination on GaN surface, while Ga 2 O 3 is still found at the surface. After thermal annealing at 710 °C in the ultrahigh vacuum (UHV) chamber and activated with Cs/O, all the GaN samples are successfully activated to the effective negative electron affinity (NEA) photocathodes. Among all samples, the GaN sample with the highest content of Ga 2 O 3 after chemical cleaning obtains the highest quantum efficiency. By analyzing the property of Ga 2 O 3 , the surface processing results, and electron affinity variations during Cs and Cs/O 2 deposition on GaN of other groups, it is suggested that before the adsorption of Cs, Ga 2 O 3 is not completely removed from GaN surface in our samples, which will combine with Cs and lead to a large decrease in electron affinity. Furthermore, the effective NEA is formed for GaN photocathode, along with the surface downward band bending. Based on this assumption, a new dipole model Ga 2 O 3 -Cs is suggested, and the experimental effects are explained and discussed.
    Print ISSN: 0021-8979
    Electronic ISSN: 1089-7550
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 97
    Publication Date: 2015-08-14
    Description: The phase transitions and ferroelectricity of LiNbO 3 and LiTaO 3 have been investigated theoretically from first principles. The phonon analyses and the molecular dynamics simulations revealed that the ferroelectric phase transition is not conventional displacive type but order-disorder type with strong correlation between cation displacements. According to the evaluated potential energy surfaces around the paraelectric structures, the large difference in ferroelectricity between the two oxides results from the little difference in short-range interionic interaction between Nb-O and Ta-O. As the results of the crystal orbital overlap population analyses, the different short-range interaction originates from the difference in covalency between Nb4 d -O2 p and Ta5 d -O2 p orbitals, particularly d xz - p x / d yz - p y orbitals ( π orbitals), from the electronic point of view.
    Print ISSN: 0021-8979
    Electronic ISSN: 1089-7550
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 98
    Publication Date: 2015-08-14
    Description: The reported values of bandgap of rutile GeO 2 calculated by the standard density functional theory within local-density approximation (LDA)/generalized gradient approximation (GGA) show a wide variation (∼2 eV), whose origin remains unresolved. Here, we investigate the reasons for this variation by studying the electronic structure of rutile-GeO 2 using many-body perturbation theory within the GW framework. The bandgap as well as valence bandwidth at Γ-point of rutile phase shows a strong dependence on volume change, which is independent of bandgap underestimation problem of LDA/GGA. This strong dependence originates from a change in hybridization among O- p and Ge-( s and p ) orbitals. Furthermore, the parabolic nature of first conduction band along X-Γ-M direction changes towards a linear dispersion with volume expansion.
    Print ISSN: 0021-9606
    Electronic ISSN: 1089-7690
    Topics: Chemistry and Pharmacology , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 99
    Publication Date: 2015-08-13
    Description: Carrier-type control of spin-glass (cluster spin-glass) is studied in order to engineer basic magnetic semiconductor elements using the memory functions of spin-glass. A key of carrier-polarity control in magnetite is the valence engineering between Fe(II) and Fe(III) that is achieved by Ti(IV) substitution. Single phases of (001)-oriented Fe 3− x Ti x O 4 thin films have been obtained on spinel MgAl 2 O 4 substrates by pulsed laser deposition. Thermoelectric power measurements reveal that Ti-rich films ( x  = 0.8) show p -type conduction, while Ti-poor films ( x  = 0.6–0.75) show n -type conduction. The systematic Fe(III) reduction to Fe(II) followed by Ti(IV) substitution in the octahedral sublattice is confirmed by the X-ray absorption spectra. All of the Fe 3− x Ti x O 4 films ( x  = 0.6–0.8) exhibit ferrimagnetism above room temperature. Next, the spin-glass behaviors of Ti-rich Fe 2.2 Ti 0.8 O 4 film are studied, since this magnetically diluted system is expected to exhibit the spin-glass behaviors. The DC magnetization and AC susceptibility measurements for the Ti-rich Fe 2.2 Ti 0.8 O 4 film reveal the presence of the spin glass phase. Thermal- and magnetic-field-history memory effects are observed and are attributed to the long time-decay nature of remanent magnetization. The detailed analysis of the time-dependent thermoremanent magnetization reveals the presence of the cluster spin glass state.
    Print ISSN: 0021-8979
    Electronic ISSN: 1089-7550
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 100
    Publication Date: 2015-08-13
    Description: We study the pair complexation of a single, highly charged polyelectrolyte (PE) chain (of 25 or 50 monomers) with like-charged patchy protein models (CPPMs) by means of implicit-solvent, explicit-salt Langevin dynamics computer simulations. Our previously introduced set of CPPMs embraces well-defined zero-, one-, and two-patched spherical globules each of the same net charge and (nanometer) size with mono- and multipole moments comparable to those of globular proteins with similar size. We observe large binding affinities between the CPPM and the like-charged PE in the tens of the thermal energy, k B T , that are favored by decreasing salt concentration and increasing charge of the patch(es). Our systematic analysis shows a clear correlation between the distance-resolved potentials of mean force, the number of ions released from the PE, and CPPM orientation effects. In particular, we find a novel two-site binding behavior for PEs in the case of two-patched CPPMs, where intermediate metastable complex structures are formed. In order to describe the salt-dependence of the binding affinity for mainly dipolar (one-patched) CPPMs, we introduce a combined counterion-release/Debye-Hückel model that quantitatively captures the essential physics of electrostatic complexation in our systems.
    Print ISSN: 0021-9606
    Electronic ISSN: 1089-7690
    Topics: Chemistry and Pharmacology , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...