Compact Einstein warped product spaces with nonpositive scalar curvature

We study Einstein warped product spaces. As a result, we prove the following: if is an Einstein warped product space with nonpositive scalar curvature and compact base, then is simply a Riemannian product space.

     

Existence results for degenerate <Emphasis Type="Italic">p</Emphasis>(<Emphasis Type="Italic">x</Emphasis>)-Laplace equations with Leray-Lions type operators

We show the existence and multiplicity of solutions to degenerate p(x)-Laplace equations with Leray-Lions type operators using direct methods and critical point theories in Calculus of Variations and prove the uniqueness and nonnegativeness of solutions when the principal operator is monotone and the nonlinearity is nonincreasing. Our operator is of the most general form containing all previous ones and we also weaken assumptions on the operator and the nonlinearity to get the above results. Moreover, we do not impose the restricted condition on p(x) and the uniform monotonicity of the operator to show the existence of three distinct solutions.     

Monitoring process for attributes with quality deterioration and diagnosis errors

The aim of this paper is to present an online economical quality-control procedure for attributes in a process subject to quality deterioration after random shift and misclassification errors during inspections. The process starts in control (State I) and, in a random time, it shifts to out of control (State II). Once at State II, the non-conforming fraction increases according to a non-decreasing function ψ(z), where z is the number of items produced after a shift. The monitoring procedure consists of inspecting a single item at every m produced items, which is examined r times independently to decide its condition. Once an inspected item is declared non-conforming, the process is stopped and adjusted. A direct search technique is used to find the optimum parameters which minimize the expected cost function. The proposed model is illustrated by a numerical example. Copyright © 2007 John Wiley & Sons, Ltd.     

Direct observation of the quantum tunneling of single hydrogen atoms with a scanning tunneling microscope

Single hydrogen atoms were imaged on the Cu(001) surface by scanning tunneling microscopy (STM). The vibrations of individual H and D atoms against the surface were excited and detected by inelastic electron tunneling spectroscopy (STM-IETS). Variable temperature measurements of H atom diffusion showed a transition from thermally activated diffusion to quantum tunneling at 60 K. Regimes of phonon-assisted and electron-limited quantum tunneling were observed. The thermal diffusion rate of D atoms varied over 7 orders of magnitude between 80 and 50 K with no transition to quantum tunneling down to a thermal hopping rate of 4x10(-7) s(-1).     

Enhanced stability of 1D molecular lines on the H-terminated Si(001) surface

We present a facile method for the self-directed growth of 1D molecular lines on the H-terminated Si(001) surface. Instead of a previously employed single dangling bond, we here employ a single H-free Si dimer as a reaction site, resulting in an enhanced stability of the radical intermediate for the O-phthalaldehyde (OP) molecule containing two carbonyl groups. This radical intermediate easily abstracts two H atoms from a neighboring Si dimer, thereby allowing the chain reaction for a 1D molecular line. Such a fabricated OP line will be stable at higher temperatures compared to previously reported alkene lines because of its enhanced stability.     

Quantum MIMO Communication Scheme Based on Quantum Teleportation with Triplet States

A novel quantum MIMO communication scheme is proposed by generalizing the wireless communication technique to the quantum field. The MIMO quantum teleportation can be implemented with triplet states in order to enhance the capacity and fidelity of the quantum channel, in which an n-qubit sequence of quantum signals can be transmitted through the MIMO quantum channel by applying the diversity technique. The quantum noise filtering is involved before the quantum signals are outputted. The analysis and discussions demonstrate that the quantum MIMO teleportation can be performed securely with high capacity and fidelity.     

Removal of nanoparticles on silicon wafer using a self-channeled plasma filament

The effective removal of nanoparticles from a silicon wafer surface was demonstrated using the self-channeled plasma filament excited by a femtosecond (130?fs) Ti:sapphire laser (?? _p=790?nm). The photoinduced self-channeled plasma filament in air reached a length of approximately 110?C130?mm from the first focal spot with diameters ranging from 40 to 50???m at input intensities of more than 1.0×10¹⁴?W/cm². By the scan of wafer using the X?CY?CZ stage during self-channeled plasma filament, the removal variation of nanoparticles on surface was observed in situ before and after the plasma filament occurred. The cleaning efficiency was strongly dependent on the gap distance between the plasma filament and the surface. The removal efficiency of nanoparticles reached 96?% with no damage to the surface when the gap was 150???m.     

Influence of polymer dielectric surface energy on thin‐film transistor performance of solution‐processed triethylsilylethynyl anthradithiophene (TES‐ADT)

This study investigates the correlation between surface energy of polymer dielectrics and the film morphology, microstructure, and thin‐film transistor performance of solution‐processed 5,11‐bis(triethylsilylethynyl) anthradithiophene (TES‐ADT) films. The low surface energy polyimide (PI) dielectric induced large grains with strong X‐ray reflections for spin‐cast TES‐ADT films in comparison to high surface en‐ ergy poly(4‐vinyl phenol) (PVP) dielectric. Furthermore, thin‐film transistors based on spin‐cast TES‐ADT films on PI dielectric exhibited enhanced electrical performance, small hysteresis, and high stability under bias stress with carrier mobility as high as 0.43 cm²/Vs and a current on/off ratio of 10⁷. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Transparent p‐NiO/n‐ZnO diodes used in circuit rectifiers

We report on the fabrication of a transparent photostable cell circuit composed of drive and resistor diodes which are face‐to‐face connected to each other with different device area. The diodes consisted of e‐beam evaporated p‐NiO on sputter‐deposited n‐ZnO for p/n diode formation on indium‐tin‐oxide glass. Our transparent diodes show photostable rectifying behavior, about 10³ on/off current ratio and even dynamic rectification at a maximum frequency of 100 Hz AC input signal in ambient light. The noticeable photo‐responsivity of the circuit was obtained only under ultraviolet (UV) light. We conclude that our transparent diode circuit is promising in enriching the field of transparent device electronics. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Local chemical distribution and electronic structure of Ge1−xTx DMS single crystals (T=Cr,Mn, Fe)

The spatial concentration distribution and local electronic structure of ferromagnetic Ge_1−xT_x (T=Cr, Mn, Fe) DMS single crystals have been investigated by using scanning photoelectron microscopy (SPEM), X-ray absorption spectroscopy (XAS), and photoemission spectroscopy (PES). It is found that doped T ions in Ge_1−xT_x crystals are chemically phase-separated, suggesting that the observed ferromagnetism arises from the phase-separated T-rich phases in Ge_1−xT_x.