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We present a surface potential based analytical model for double gate tunnel field effect transistor (DGTFET) for the current, terminal charges, and terminal capacitances. The model accounts for the effect of the mobile charge in the channel and captures the device physics in depletion as well as in the strong inversion regime. The narrowing of the tunnel barrier in the presence of mobile charges in the channel is incorporated via modeling of the inverse decay length, which is constant under channel depletion condition and bias dependent under inversion condition. To capture the ambipolar current behavior in the model, tunneling at the drain junction is also included. The proposed model is validated against TCAD simulation data and it shows close match with the simulation data.

Interlayer exchange coupling (IEC) between GaMnAs layers in GaMnAs/InGaAs/GaMnAs tri-layers was studied by magnetization measurements. Minor hysteresis loops are observed to shift in a direction indicating the presence of ferromagnetic (FM) IEC in the structures. The strength of the FM IEC clearly exhibits an exponential decrease with respect to nonmagnetic InGaAs spacer thickness. The fitting of the spacer thickness dependence of the FM IEC to an exponential decay function provides a decay length of 3.3±0.3 nm, which is relatively large compared to metallic multilayers, indicating a long ranged IEC in systems based on GaMnAs.

This study proposes a method for evaluating the axial decay length of the plasma pressure in detached helium plasmas with a fixed-point laser Thomson scattering and spectroscopic measurements in the linear divertor plasma simulator NAGDIS-II. By controlling the neutral gas pressure, the highly volume-recombining region called the “recombination front” was moved along the magnetic field. The differential terms for the electron pressure and the recombination-front position with respect to the neutral pressure were obtained. By using these two terms, the decay length of the plasma pressure was qualitatively calculated. In addition, from the movable Langmuir probe measurement, difference between the locally estimated decay length around the recombination front and the decay lengths over a wide axial range was discussed. The proposed method can be applied even in the huge heat flux condition where direct-contact measurements such as the Langmuir probe are not available.

The defect detection sensitivity of magnetic nanoemulsions (MNEs) stabilized with different functional moieties such as anionic surfactant, co-polymer and a weak polyelectrolyte is reported here. The visually discernible colour contrast over the defective regions and the corresponding Bragg’s reflection, originating from the linear chain-like structures formed by the leakage magnetic flux are experimentally measured and compared with the theoretically obtained profiles. The linear chain-like structures, formed by the MNEs, are also visualized using atomic force and optical phase contrast microscopy studies. Defect detection studies are carried out on carbon steel samples with artificially made defects (rectangular slots) and the variations in defect detection sensitivity (colour contrast) are assessed under different stabilizing moieties. It is found that the electrostatically stabilized MNEs exhibited superior defect detection sensitivity, as compared to the polymeric stabilizers. The microscopic origin for sensitivity variations, is studied by measuring the inter-droplet forces and hydrodynamic diameter. The inter-droplet force measurements show that the lower decay length is better for improving the defect detection sensitivity. Through image processing and intensity profiling, the defect widths are accurately estimated, which are in good agreements with the actual defect dimensions. The intensity profiles are found to vary linearly with the defect depth for the shallower defects. These results are useful to tailor MNEs with superior defect detection sensitivity and long-term stability towards development of MNE-based thin film sensors for automated and superior defect detection strategies.

Thirty years ago there was considerable excitement over the first report of a long-ranged “hydrophobic force” between solids that were not wet by water (Israelachvili and Pashley, Nature 1982, 300 , 341–342). Many of the subsequent measurements have been reexamined and found not to support the existence of a long-range hydrophobic force. The principal difficulty was that hydrophobic solids frequently experience other forces, which obscured or were mistaken for a hydrophobic force. In this paper, we review the surviving evidence for a long-range hydrophobic force and find that there is only supporting evidence in a total of two papers, one old and one new, where net attractive forces were measured at separations greater than about 5–6 nm. Thus the evidence is scarce. In contrast there are new experiments showing no such force, thereby arguing against the universality of a measureable hydrophobic force beyond about 6 nm. Since solvent water is common to the experiments, such evidence makes it difficult to describe a universal mechanism for a long-ranged hydrophobic force based on water structure. There are also new measurements that are consistent with a hydrophobic force with a decay length in the range 0.3–1.0 nm. In particular, attractive forces have been measured on small radius surfaces (8–50 nm) consistent with a hydrophobic force with a decay length of 0.5–0.6 nm, and a variety of net repulsive measurements are consistent with an attractive hydrophobic force that has a decay length of 0.3–1.0 nm. We also discuss some new measurements, which are consistent with cavitation, and not a surface force that acts at a distance.

The narrow scrape-off layer power component observed in COMPASS inner wall limiter circular discharges by means of IR thermography is investigated by Langmuir probes embedded in the limiter. The power flux profiles are in good agreement with IR observations and can be described by a double-exponential decay with a short decay length (

We studied electronic properties of atomic-scale dangling bond (DB) and DB wires on Si(100)-2 × 1:H surfaces using a ultrahigh vacuum scanning tunneling microscope (UHV-STM). The decay of the near-midgap DB-states induced by an unpaired DB depends on the crystalline orientation of the Si(100) surface. The decay length of the DB-states of an unpaired DB wire can be ~ 2.5 nm along the dimer row direction. The perturbation from an unpaired DB to an adjacent paired DB is also demonstrated. The results are in good agreement with density functional calculations.

In various models of supersymmetry (SUSY), the lightest superparticle in the minimal SUSY standard model sector, which we call MSSM-LSP, becomes unstable. Then, we may observe the decay of the MSSM-LSP in the detector at the LHC experiment. We show that the discovery of such a decay process (and the determination of the lifetime of the MSSM-LSP) may be possible at the LHC even if the decay length of the MSSM-LSP is much longer than the size of the detector; sizable number of the MSSM-LSPs decay inside the detector if the lifetime is shorter than 0.01-1 millisec. We also discuss the implications of the study of the MSSM-LSP decay for several well-motivated SUSY models., Comment: 13 pages, 4 figures

In supersymmetric (SUSY) models with the gravitino being the lightest SUSY particle (LSP), the SUSY breaking scale (i.e., the gravitino mass) could be determined by measuring the lifetime of the next-to-lightest SUSY particle (NLSP). However, for an ultralight gravitino of mass of O(1) eV, which is favored cosmologically, the determination of the SUSY breaking scale, or the gravitino mass, is difficult because the NLSP decay length is too short to be measured directly. Recently we proposed a new determination of the gravitino mass by measuring a branching fraction of two decay modes of sleptons. In this paper, we investigate the prospects for determining the gravitino mass at LHC. For demonstration we take some explicit gauge-mediation models and show that the gravitino mass can be determined with an accuracy of a few 10% for an integrated luminosity 10-100 fb^{-1}., Comment: 16 pages, 10 figures

Corrosion is typical of the damage that occurs in ageing pressure vessels and pipelines used in industrial processes as a result of reactive products inside or harsh environmental conditions on the outside. Structural integrity of such components needs to be evaluated periodically to establish the continued suitability of the vessels under operating conditions. The present paper develops a method for Level 2 (as categorized by API 579) fitness-for-service (FFS) evaluation of spherical pressure vessels with localized corrosion. The decay lengths for spherical shells subject to different sizes of corroded areas are calculated based on elastic effects in shells so as to identify the reference volume participating in plastic action. Lower bound “remaining strength factors” of spherical pressure vessels containing corrosion damage are formulated by the application of Mura's variational formulation and the m α -multiplier method. Three alternative design recommendations are given. The effectiveness of the proposed methods is evaluated and demonstrated through illustrative examples and comparison with Level 3 inelastic finite element analyses.

Spherical shapes are used in industry as hemispherical vessel heads or high-pressure storage vessels due to the inherent strength associated with the shape. Structural integrity of such components needs to be evaluated periodically to prevent failure of the vessels under operating conditions. The paper develops a method for Level 2 (as defined by API 579 [(2000). Fitness-for-service, API 579. Washington, DC: American Petroleum Institute]) fitness-for-service estimation of spherical shapes subject to local hot spots where the temperatures are elevated due to local damage. The decay length for spherical shells is determined, and the size of hot spot to be identified as local is proposed. A lower bound “remaining strength factor” (RSF) for spherical pressure vessels containing hot spots is formulated by the application of Mura's variational formulation and the m α -multiplier method. The effectiveness of the proposed Level 2 method is evaluated and demonstrated through an example.

Ultrashallow junctions in semiconductors and multi-quantum wells (MQW) in lasers demand high depth resolution for accurate depth profiling. SIMS has been widely used in depth profiling and the use of ultralow-energy SIMS has demonstrated a narrower surface transient and an improvement in depth resolution. In this work, we use an ATOMIKA 4500 SIMS depth profiler with O 2 + primary ions at an ultralow-energy (Ep) of 250 eV and incidence angles (0) between 0 and 70° without oxygen flooding. A sample with 10 delta layers of Si 0.7 Ge 0.3 nominally grown 11 nm apart is used. We observe that for applications like characterizing ultrashallow junctions, 0 ∼ 0° provides the narrowest surface transient (z tr ) of 0.7 nm, which is marginally better than at 0 ∼ 40° with z tr of 1.0 nm. The depth resolution denoted by the full width at half maximum (FWHM) of the 70 Ge + peaks is comparable for both θ ∼ 0 and 40° at 1.6 and 1.4 nm, respectively. However, in the case of MQW profiling, whereby the quantum wells are normally located deeper, 0 ∼ 40° is preferable. At this angle, the average sputter rate of 47 nm min -1 nA -1 cm -2 is significantly higher, more than double that at 0 ∼ 0° and a better depth resolution with decay length (λ d ) of 0.64 nm compared to 0.92 nm at 0 ∼ 0°. Moreover, the dynamic range possible is also better at 0 ∼ 40°. 0 ∼ 60° is not ideal, even though there is no sign of the onset of roughening. Although the higher sputter rate is an advantage, the depth resolution deteriorates as the profile gets deeper.

The mean lifetime of the tau lepton is measured from the decay length distribution of 3-prong tau decays from e + e − collisions at the ϒ ( 4 S ) resonance. A data sample of 80.0 fb−1 collected with the BaBar detector at the PEP-II B Factory is used for this measurement. The measured tau lifetime is: τ τ = 289.40 ± 0.91 (stat.) ± 0.90 (syst.) fs . All the results are preliminary.

Fluid slip along hydrophobic microchannel walls has been observed experimentally by Tretheway and Meinhart [Phys. Fluids, 14 (3) (2002) L9]. In this paper, we show how fluid slip can be modeled by the lattice Boltzmann method and investigate a proposed mechanism for the apparent fluid slip [Phys. Fluids (2003)]. By applying an exponentially decaying hydrophobic repulsive force of 4x10^-^3 dyn/cm^3 with a decay length of 6.5 nm, an effective fluid slip of 9% of the main stream velocity is obtained. The result is consistent with experimental @m-PIV data and with the proposed mechanism.

Heat conduction in circular cylinders of functionally graded materials and laminated composites is studied with emphasis on the end effects. By means of matrix algebra and eigenfunction expansion, the decay length that characterizes the end effects on the thermal filed is evaluated and the 2D solution as a useful approximation assessed.

This report provides a review of the main algorithms for offline inclusive b-tagging developed within the CMS community. Two b-tag algorithms, one based on the impact parameter measurement and the other based on the secondary vertices are dicdussed. The performance of these algorithms are presented for several jet transverse energies and pseudorapidity regions. An additional decay length based b-tag is also described and its preliminary performance is presented.

The measurements of Rb = σ(e+e− → b b )/σ(e+e− → q q ) at centre-of-mass energies above the Z pole using data collected by the LEP experiments from 1995 to 1999 are summarised. The measurements are performed using b-tagging methods that exploit the relatively large decay length of b hadrons. A preliminary combination of the Rb measurements is also presented.

Computer models for following stimulus gradients in two-dimensional space were evaluated to determine the relative advantages of different strategies and to identify the issues that must be addressed in making such a comparison. The simulations were implemented with emphasis on making them as general and free of specific assumptions as possible. Performance was defined as progress along the gradient divided by the cost of the movements and time taken. Plausible values of costs were taken from data on animal energetics. The models also included various kinds of noise that limit performance. These included unintended variations and biases in motor outputs as well as sensory inputs. An initial guess at appropriate noise levels led to performance worse than that observed in experiments with leukocytes. Reduced noise levels gave good agreement. Under these, more appropriate, conditions, peak performance for the various models varied from 24 to 99% of the maximum possible. The threshold gradient required to provide performance equal to 1% of the maximum possible varied from 800 to 5000 searcher diameters per gradient decay length. Some models performed well only over a narrow range of gradients. There was no indication of a tradeoff between sensitivity to shallow gradients and high performance in steep gradients. The model of tropotaxis (simultaneous, spatial comparison) with movement in any direction was superior in having the lowest threshold, the highest maximum performance, requiring the fewest parameters to fit, and performed well over the widest range of gradients. This result suggests that amoeboid cells and echinoderms might be particularly well suited to following gradients. The modeling demonstrates the need to obtain quantitative estimates for a number of parameters (relating costs and noise levels) for a more rigorous understanding of the relative advantages of these different strategies.

We have searched for time-dependent B s 0 – B s 0 mixing using a sample of 400 000 hadronic Z 0 decays collected by the SLD experiment at the SLC. The analyses take advantage of the excellent vertexing efficiency and resolution of the pixel-based CCD Vertex Detector which provides a B decay length resolution of approximately 100 μm . All analyses determine the B hadron flavor at production by exploiting the large forward–backward asymmetry of polarized Z 0 → b b decays. This flavor tag is enhanced by incorporating additional information from the hemisphere opposite that of the reconstructed B decay. In one analysis, B decay vertices are reconstructed inclusively with a topological technique, and separation between B s 0 and B s 0 decays is based on the reconstruction of a “charge dipole” of the topological vertices to exploit the B s 0 →D s − cascade charge structure. The other two analyses select semileptonic decays to tag the B flavor at decay and reconstruct the B decay vertex by intersecting the lepton with either all tracks in the nearest jet or the trajectory of a topologically reconstructed D vertex. The three analyses are combined to exclude the following values of the oscillation frequency: Δ m s 6.0 ps −1 Δ m s ps −1 . Future prospects are outlined.

It is well known that in some cases, the Johnson–Kendall–Roberts model is not adequate to deduce adhesion energies from pull-off force values obtained from surface forces measurements. Then, the decay length of the interaction becomes significant, and the data are more adequately modelled by the Maugis model (D. Maugis, J. Colloid Interface Sci, 150 (1992) 243). In this paper, we consider the problem of modelling the data when the interaction is made up of two components, with very different decay lengths. We show that this case cannot be handled by the Maugis model directly and propose an adequate generalization of the Maugis model. This general model allows one to accurately split the total adhesion energy into its various components.

The production rate of Σ − in Z 0 decays is measured by DELPHI and the result is presented and compared to JETSET. Due to their long decay length, the decay of Σ ± often takes place outside the three-layered microvertex detector, which makes a direct determination of their track parameters possible. A direct measurement of the Ξ − and Ξ + lifetimes and masses is also presented. The production rate − + Ξ + > qq in all hadronic events is measured and compared to the JETSET model as well as the production rate − + Ξ + > bb in bb events.

The decay length method, used to measure the τ lifetime in 3-prong τ decays, is described. The most recent lifetime measurements made using this method at Z0 energies from the OPAL, ALEPH, DELPHI and SLD experiments are summarized. These measurements of the τ lifetime are seen to be statistics limited.

Computed disjoining pressure isotherms are compared with experimentally measured isotherms obtained using ellipsometry. A detailed charge regulation model for amphoteric surfaces has been used to describe the glass-brine interface. The results of this model together with an electrochemical description of the mercury-brine interface have been used to numerically compute disjoining pressure isotherms for aqueous films between glass and mercury. These isotherms allow us to predict the stability of aqueous films in various systems of interest. A comparison between measured and computed disjoining pressure isotherms indicates a good agreement when a decay length of 35 A is chosen for the hydration forces. The effects of brine pH, electrolyte concentration, and the potential on the mercury surface on the disjoining pressure isotherms and on the stability of thin aqueous films are discussed.

A tunneling study is performed on the surface of the normal-conducting copper oxide La 1.5 Ba 1.5 Cu 3 O 7- y (LBCO) in the N (LBCO)-S (HoBa 2 Cu 3 O 7- y (HBCO)) bi-layer system. The measured tunneling d I /d V curve has a gap-like structure which is similar to those of high- T c superconductors. The peak-to-peak voltage 2Δ in the tunneling d I /d V curve exponentially decreases with increasing LBCO layer thickness. These facts suggest that superconductivity is induced in the LBCO layer. The characteristic decay length ξ of Δ is 260±50 nm , which is two orders larger than the value expected from the conventional theory of the proximity effect.

The decay length of shear diffusion in magnetic fluids is calculated for various field configurations. This provides information on the rotational friction coefficient η r , and the magnetic relaxation time τ. A simple experimental set-up is proposed.

Uniaxial tensile tests to failure have regularly been employed to characterise the material properties of various biological tissues, ranging from heart valves (Anssari-Benam et al., 2011) and arteries (Teng et al., 2009; Lillie et al., 2010) to tendons (Legerlotz et al., 2010), intervertebral discs (Nerurkar et al., 2010) and liver (Brunon et al., 2010), providing valuable quantitative data on important mechanical properties such as ultimate stress, strain and modulus. These properties, by definition, are intrinsic material properties and thus should not depend on the geometry of the specimen

We have observed ballistic electron transport beyond 100 microm in the 2D electron system of an ultra-high mobility GaAs(AlGa)As heterostructure employing a magnetic electron focusing technique through wide point contacts. The amplitude of the characteristic magneto-oscillations is found to depend exponentially on electron propagation distance with a decay length λ a = 15 microm. λ a differs by about a factor of 2 from the mobility mean free path of 28 microm. This may indicate the determination of a different angular average of scattering events in focusing experiments as compared to standard mobility measurements.

We appreciate the detailed response from Professor Horgan, discussing our letter to the editor concerned with end effects when mechanical testing soft tissues (Anssari-Benam et al., 2012a), and providing further insightful analysis. The concepts of end effects and characteristic decay length have indeed been well established for a long time in the context of solid mechanics, with substantial contributions from Professor Horgan, towards establishing theoretical and analytical criteria for their characterisation, as referenced in our previous publication (Anssari-Benam et al., 2012b; from Horgan (1972), Choi and Horgan (1977).

A tunneling study is performed on the surface of a normal-conducting copper oxide La 1.5 Ba 1.5 Cu 3 O 7−y (LBCO) in S(HoBa 2 Cu 3 O 7−y (HBCO))-N(LBCO) bi-layer system. Measured tunneling dI/dV curve has a gap-like structure. The peak-to-peak voltage 2Δ in the tunneling dI/dV curve exponentially decreases with increasing LBCO layer thickness. These facts suggest that a superconductivity is induced in the LBCO layer. The characteristic decay length ξ of Δ is 260±50 nm, which is two orders larger than the value expected from the conventional theory of the proximity effect.

Hydration forces between two hydrophilic surfaces are generated by the overlap between the two polarization layers which are formed near each of them. The differential equation that describes the polarizatin field as well as the corresponding boundary conditions are derived on the basis of electrostatics. Expressions for the decay length and for the magnitude of the force have been derived and compared with experiment.

Almost all analyses of large structures neglect local effects due to the application of loads and due to the transfer of loads between structural elements. In recent years, however, the use in aircraft structures of highly anisotropic materials, such as graphite/epoxy, has motivated more detailed studies of the applicability of Saint-Venant's principle. In this paper in graphite/epoxy is analysed using the finite element method (FEM). The influence of anisotropy and transition from a thicker to a thinner laminate cross-section (ply-drop) is investigated. The characteristic decay length which is large for highly anisotropic materials is lessened by a change in thickness.

We have investigated the forces between two surfaces, immersed in a dilute electrolyte solution, interacting specifically with the ions that are in their immediate vicinity. It is found that at large separations the free energy decays exponentially (the decay length being approximately half the Debye length) with separation, while the magnitude of the force depends on the physical properties of the surfaces and their interactions with the nearby ions. This long-range attractive force could well represent a case for the electrostatic nature of the surface-specific very long-range “hydrophobic” interaction.

Buttiker's analysis of the Larmor clock is extended to the local situation in which a uniform transverse magnetic field is confined to an arbitrary part of a barrier. The resulting local characteristic electron-barrier interaction times for transmission and reflection are complex quantities whose real and imaginary parts are measurable, at least in principle. Analytic expressions for the local interaction times of a rectangular barrier are derived and their properties investigated. The effects of a multiple image potential are examined numerically. Quite apart from the question of local interaction times, it is shown that in the tunnelling regime the transverse magnetic field produces significant precession only when it extends to within a decay length κ−1 of either edge of a rectangular barrier.

The redistribution of As from a shallow As-implant (5 keV) in Si following oxygen bombardment has been studied by grazing exit RBS. The oxygen bombardment was performed in an ion implanter (12.5 keV O+, room temperature and 40 K), and a reactive ion elcher (1.7 keV O+2). For 12.5 keV O+ bombardment the As redistributes very rapidly in the sample; displacements up to 50 nm are observed. Implantation at 40 K shows only a very small reduction in spreading of the As distribution indicating a very low activation energy for the defect-induced diffusion. Bombardment with 1.7 keV O+2 does not broaden the internal As distribution as much as at 12.5 keV O+ but our results indicate that the As-atoms segregate at the oxide-silicon interface. Enhanced segregation in the reactive ion etcher results in a much larger decay length than under SIMS-bombardment conditions.

Annealing behaviors of the activation energy for electrical conduction, the optical gap, and the spin density in amorphous Si are investigated. It is found that the Fermi level shifts downwards with the decrease of the spin density, increasing the decay length of the wave function of localized state at the Fermi level. The downward shift of the Fermi level suggests that the localized states in the upper energy region in the gap are annealed out more easily than those in the lower one.

Heavy fourth-generation neutrinos ν4 produced at colliders via Z 0 → ν 4 ν 4 may be detected via their decays in flight ν4 → l + W (virtual) if the neutrino mixing matrix elements U4l (l = e, μ, τ) have appropriate size. For neutrino mass m 4 = 15 GeV and |U 4l |⋍10 −4 , the mean decay length is about 40 cm and scales with |U|−2 (m4)−6 for mτ⪡m4⪡MZ. Searches via W → Lν4 are another possibility.

Critical currents for triple layer superconducting-normal metal-superconducting (SNS) junctions have been measured with the normal metal in the thick-clean limit in order to determine the spatial variation of the order paremeter as a function of magnetic field (H). Critical currents fall exponentially with H as might be expected if the decay length, K -1 N , varies linearly with H. The diffusivity, D N , derived from the measured depairing parameter, α =D N eH/c, agrees with the diffusivity determined from resistivity measurements.