World Library  

 
  • Cover Image

Journal of Applied Physics : Effect of grain refinement on enhanci...

By: A. Malagoli, V. Braccini, M. Tropeano, M. Vignolo, C. Bernini et al

Description: Ex situ powder-in-tube MgB2 tapes prepared with ball-milled, undoped powders showed a strong enhancement of the irreversibility field H∗, the upper critical field Hc2, and the critical current density Jc(H) together with the suppression of the anisotropy of all of these quantities. Jc reached 104 A/cm2 at 4.2 K and 10 T, with an irreversibility field of about 14 T at 4.2 K, and Hc2 of 9 T at 25 K, high values for not-doped MgB2. The enhanced Jc and H∗ values...

Read More
  • Cover Image

Physics of Plasmas : Modeling of an advanced concept of a double s...

By: L. Garrigues, C. Boniface, G. J. Hagelaar, and J. P. Boeuf

Description: We present a study of the principle and operation of a two-stage Hall effect thruster, the SPT-MAG, using a two-dimensional quasineutral hybrid model coupled with a Monte Carlo simulation of electron transport. The purpose of the two-stage design is the separation of ion production and acceleration in two separate chambers, the ionization stage and the acceleration stage, with separate control of acceleration voltage and total ionization. The originality of ...

Read More
  • Cover Image

Journal of Applied Physics : Al-doped ZnO nanocrystals

By: Pratibha Kadam, Chitra Agashe, and Shailaja Mahamuni

Description: Al3+-doped ZnO nanocrystals were differently obtained by wet chemical and an electrochemical route. An increase in forbidden gap due to change in crystal size and also due to Al3+ doping in ZnO is critically analyzed. The Moss–Burstein type shift in Al3+-doped ZnO nanocrystals provides an evidence of successful Al3+ doping in ZnO nanocrystals. The possibility of varying the carrier concentration in ZnO nanocrystals is the indirect implication of the present investigations.

Read More
  • Cover Image

Applied Physics Letters : Absence of elastic clamping in quantitat...

By: David A. Scrymgeour and Julia W. P. Hsu

Description: We establish that clamping effects, which limit accurate determination of piezoelectric responses in bulk materials and films using piezoelectric force microscopy (PFM), are not present when measuring discrete nanostructures with radii less than five times the tip radius. This conclusion is established by comparing the piezoelectric response in ZnO rods using two electrode configurations: one with the conducting atomic force microscopy tip acting as the top ...

Read More
  • Cover Image

The Journal of Chemical Physics : Analysis of polyatomic molecules...

By: Peter C. Chen and Kamilah Mitchell

Description: The peak-sorting capabilities of high resolution coherent two-dimensional (2D) spectroscopy provide a new way of dealing with severe rotational congestion. This paper describes the application of this technique to the polyatomic molecule, NO2. NO2 is a primary component of photochemical smog and has a notoriously complex and congested spectrum that extends from the infrared to the ultraviolet regions. This spectrum is infamous for having an unusually high de...

Read More
  • Cover Image

Biblioteca Hispanica : Programs of Natural History and Physiology ...

By: Sandalio of. Pereda and Martinez
Read More
  • Cover Image

Journal of Applied Physics : Spectroscopic determination of electr...

By: J. E. Maslar, W. S. Hurst, and C. A. Wang

Description: Phonon-plasmon coupled mode Raman spectra of n-type GaSb were measured at room temperature as a function of electron concentration. These spectra were obtained using an optical system based on 752.55 nm excitation. Utilization of this wavelength permits greater sensitivity to GaSb coupled mode Raman scattering over a wider doping range than is possible with visible wavelength excitation-based systems. A relatively simple spectral model for the electronic con...

Read More
  • Cover Image

Biblioteca Hispanica : Notions of Natural History, to Reach Children

By: Jose Maria Solano and Eulate
Read More
  • Cover Image

Journal of Applied Physics : Thermal peculiarity of AlAs-capped In...

By: V. G. Dorogan, Yu. I. Mazur, J. H. Lee, Zh. M. Wang, M. E. Ware et al

Description: GaAs and AlAs thin capping layers as well as postgrowth rapid thermal annealing (RTA) were applied to InAs quantum dots (QDs) grown by molecular beam epitaxy to study the tunability of optical properties of QDs by photoluminescence (PL) methods. The PL of AlAs-capped QDs shows double-peak structure, as opposed to GaAs-capped QDs, which is due to the formation of two families of QDs in the AlAs-capped sample confirmed by the power dependent PL measurements. T...

Read More
  • Cover Image

Applied Physics Letters : Ultrafast carrier capturing in GaInP/Er,...

By: Y. Terai, K. Hidaka, K. Fujii, S. Takemoto, M. Tonouchi et al

Description: Carrier capturing in GaInP/Er,O-codoped GaAs (GaAs:Er,O) /GaInP laser diodes (LDs) was investigated by means of the threshold current density (Jth) of laser emission. The Er-doped LDs showed laser emission of the GaAs band edge at room temperature, and its Jth increases with the Er flow rate during the growth. In the dependence of Jth on reciprocal cavity length, the effective gain factor of the LDs decreased by the codoping of Er and O. These results r...

Read More
  • Cover Image

Journal of Applied Physics : Mechanical behavior of stressed films...

By: Conal E. Murray and K. L. Saenger

Description: The effects of stressed thin films on substrates that possess anisotropic elasticity have been measured and modeled. Substrate curvature induced by a uniform, stressed film will be axisymmetric for substrates possessing greater than twofold in-plane symmetry, and anisotropic for twofold symmetric substrates. For a (011) Si substrate, the difference between the curvature along the 〈110〉 and 〈100〉 principal axes varies by approximately 47%. A simple, analytica...

Read More
  • Cover Image

Review of Scientific Instruments : Resistivity and thermopower mea...

By: Ajay Soni and G. S. Okram

Description: Automated precision measurement setups for electrical resistivity of eight metallic samples simultaneously and thermoelectric power of different types of samples in the temperature range of 5–325 K have been developed. The details of the setups and their capabilities have been described. Usually each run takes nearly 5 h and typical error is within 3% and 4%, respectively. The results of high purity Nb and Pt samples are used as examples to demonstrate this.

Read More
  • Cover Image

Journal of Mathematical Physics : Symmetry, full symmetry groups, ...

By: Biao Li, Wang-Chuan Ye, and Yong Chen

Description: The Lie symmetry algebra of a generalized Davey–Stewartson (GDS) system is obtained. The general element of this algebra depends on eight arbitrary functions of time, which has a Kac–Moody–Virasoro loop algebra structure and is isomorphic to that of the standard integrable Davey–Stewartson equations under certain conditions imposed on parameters and arbitrary functions. Then based on the symmetry group direct method proposed by Lou and Ma [J. Phys. A 38, L12...

Read More
  • Cover Image

Journal of Applied Physics : Electric-field-controlled electron re...

By: Y. Y. Liao, D. S. Chuu, and S. R. Jian

Description: This study investigates phonon-induced electron relaxation in a lateral double quantum dot that is embedded in a suspended slab. Exact calculations are made in electric fields. The dependence of the relaxation rate on the parameters of the dots and the slabs is analyzed. Numerical results indicate that the relaxation rate depends strongly on the phonon character of the slab. Unlike in the bulk environment, phonon-subband quantization clearly influences the b...

Read More
  • Cover Image

Journal of Applied Physics : Multiferroic properties of Ni0.5Zn0.5...

By: Hongfang Zhang, Siu Wing Or, and Helen Lai Wa Chan

Description: We present a powder-in-sol precursor hybrid processing route to synthesize dense, homogenous, and fine-grained Ni0.5Zn0.5Fe2O4–Pb(Zr0.53Ti0.47)O3 (NZFO–PZT) multiferroic ceramic composites and report their ferromagnetic-ferroelectric characteristics. Nanosized NZFO ferromagnetic powders are dispersed into PZT ferroelectric sol-gel precursor and uniformly distributed slurry is prepared by ball-milling mixing of the powder-precursor suspension prior to be sint...

Read More
  • Cover Image

Physics of Plasmas : High intensity, plasma-induced emission from ...

By: Qingliang Liao, Ya Yang, Liansheng Xia, Junjie Qi, Yue Zhang et al

Description: High intensity electron emission cathodes based on a well-aligned ZnO nanorod array were fabricated. An investigation of the properties of the plasma and the electron beams produced by ZnO nanorod array cathodes was presented. Intense current electron beams were obtained from the cathodes. At an electric field of 7–8 V/μm and pulse duration of ∼ 100 ns, the highest emission current density reached 76–91 A/cm2. The production mechanism of the electron beams w...

Read More
  • Cover Image

Physics of Fluids : Quantifying the linear stability of a flowing ...

By: A. Kerem Uguz and N. Aubry

Description: Motivated by the destabilization of a two-fluid layer flowing in a microchannel for efficient mixing or droplet formation, we study quantitatively the linear stability of the interface between two liquids subjected to an electric field parallel or normal to the flat interface. In the case of fast electric charge relaxation times, the equations for the perturbation can be significantly reduced [ A. K. Uguz, O. Ozen, and N. Aubry, Phys. Fluids 20, 031702 (2008...

Read More
  • Cover Image

Journal of Applied Physics : Electronic properties of (Ga,Mn)N thi...

By: S. Granville, B. J. Ruck, A. R. H. Preston, T. Stewart, F. Budde et al

Description: Optical and dc resistivity measurements as well as x-ray spectroscopies have been performed on (Ga,Mn)N films containing Mn at up to 11 at. %. The results indicate that at higher Mn contents, the Fermi level is situated within extended states, while GaN host interband optical transitions are unaffected. The Mn state is confirmed to be 3d5, as in the case of lower Mn content films; however, the high Mn content merges the 3d levels into a band located just bel...

Read More
  • Cover Image

Journal of Applied Physics : Composition dependence of electronic ...

By: G. He, L. D. Zhang, G. W. Meng, G. H. Li, G. T. Fei et al.

Description: Composition-dependent electronic structure and optical properties of Hf1−xSixOy (0.1 ≤ x ≤ 0.6) gate dielectrics on Si at 450 °C grown by UV-photo-induced chemical vapor deposition (UV-CVD) have been investigated via x-ray photoemission spectroscopy and spectroscopy ellipsometry (SE). By means of the chemical shifts in the Hf 4f, Si 2p, and O 1s spectra, the Hf–O–Si bondings in the as-deposited films have been confirmed. Analyses of composition-dependent ban...

Read More
  • Cover Image

The Journal of Chemical Physics : Glassy properties and viscous sl...

By: Kristine Niss, Cécile Dalle-Ferrier, Valentina M. Giordano, Giulio Monaco, Bernhard Frick et al

Description: We present an extensive analysis of the proposed relationship [ T. Scopigno et al., Science 302, 849 (2003) ] between the fragility of glass-forming liquids and the nonergodicity factor as measured by inelastic x-ray scattering. We test the robustness of the correlation through the investigation of the relative change under pressure of the speed of sound, nonergodicity factor, and broadening of the acoustic exitations of a molecular glass former, cumene, and...

Read More
 
1
|
2
|
3
Records: 1 - 20 of 45 - Pages: 



Copyright © World Library Foundation. All rights reserved. eBooks from World Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.