bluuebunny/crossref_metadata_2025 huggingface dataset:
Is Life Getting Better?
Authors: Veenhoven Ruut
Published: October 2005

Abstract. Human society has changed greatly over the past centuries and this process of “modernization” has profoundly affected the lives of individuals; currently we live quite different lives from those our forefathers lived only five generations ago. There are differences of opinion as to whether we live better now than before, and consequently there is also disagreement as to whether we should continue modernizing or rather try to slow the process down. Quality of life in a society can be measured by how long and happy its inhabitants live. Using these indicators I assessed whether societal modernization has made life better or worse. First, I examined some findings from present day survey research. I started with a cross-sectional analysis of 90 nations and found that people live longer and happier in today's most modern societies. Second, I examined trends in 10 modern nations over the last 30 years and found that happiness and longevity have increased in most cases. Third, I considered the long-term and review findings from historical and comparative anthropology, which show that we lived better in the early hunter-gatherer society than in the later agrarian society. Together these data suggest that societal evolution has worked out differently for the quality of human life, first negatively, in the change from a hunter-gatherer existence to agriculture, and next positively, in the more recent transformation from an agrarian to an industrial society. We live now longer and happier than ever before.
Continental aerosol properties inferred from measurements of direct and diffuse solar irradiance
Authors: Marsden David C. , Valero Francisco P. J. , Bush Brett C.
Published: October 2005

Aerosol particles affect the global energy budget and Earth's climate through the absorption and scattering of both solar and terrestrial radiation. Here we present a study of column‐averaged aerosol optical properties derived from clear‐sky measurements of the direct and diffuse components of the solar downwelling spectral and broadband irradiance during a 10‐day observation period at the Atmospheric Radiation Measurement (ARM) facility in central Oklahoma in the fall of 2001. Using a radiative transfer model and Mie calculations of the optical properties of standard continental aerosol components and assuming a constant aerosol composition with altitude, we determine the phenomenological aerosol model that best fits both the direct and diffuse spectral irradiances. Internal and external homogeneous aerosol mixtures were considered, along with single‐aerosol and coated sphere models. We find that the irradiance data is well fit statistically by at least one of the models for every clear‐sky time considered during the observations period, with no excess gaseous absorption required to fit the data. By far the best fitting model consisted of ultrafine (∼5–30 nm radius) coated spheres with absorbing black carbon cores and nonabsorbing shells of water or a similar substance. The mean value of the 500‐nm aerosol single‐scattering albedos for the entire 10‐day period was 0.76. These results indicate that absorbing carbonaceous aerosols can have a significant radiative impact even in rural settings.
Finite volume multiscale finite element method for solving the groundwater flow problems in heterogeneous porous media
Authors: He Xinguang , Ren Li
Published: October 2005

In this paper we present a numerical method, the finite volume multiscale finite element method (FVMSFEM), for solving the groundwater flow problems in heterogeneous porous media spanning over many scales. This method is based on an efficient coupling between the finite volume discretization and the multiscale finite element base functions. It can efficiently capture the large‐scale structure of the solution on a coarse grid without resolving all the small‐scale features and is locally conservative. The underlying idea is to estimate the macroscopic fluxes across the finite control volume interface segments, which bring the local small‐scale information of the medium property to the large scales, by employing the multiscale finite element base functions. We describe the strategy for constructing such a method on the basis of the transient flow problems in porous media. Numerical experiments are carried out for groundwater flow in porous media with a random lognormal conductivity field to demonstrate the efficiency and accuracy of the developed method.
Mantle and gully associations along the walls of Dao and Harmakhis Valles, Mars
Authors: Bleamaster Leslie F. , Crown David A.
Published: October 2005

Evaluation of high‐resolution images allows a systematic characterization of the walls of Dao and Harmakhis Valles, Mars. Variations in wall morphology are classified into three archetypes (exposed, mantled, and incised). Gullies are exposed by removal of semi‐competent mantling deposits, suggesting progressive development of feature‐types in an idealized sequence from i) mantled walls, to ii) incised mantle, and eventually iii) walls that display exposed gullies. Analysis of latitude, elevation, and wall orientation of 420 representative sample sites reveals spatial patterns that display preferential clustering of the two end member morphologies: exposed gullies are favored at lower latitude, higher elevation, and on east facing walls; mantled walls are more prevalent at higher latitude, lower elevation, and on south and southwest facing walls. These morphologies and their patterns are consistent with the hypothesis that gullies emerge from beneath an ice‐rich mantle that is degrading in response to local variations in total solar insolation.
ICESat range and mounting bias estimation over precisely‐surveyed terrain
Authors: Martin C. F. , Thomas R. H. , Krabill W. B. , Manizade S. S.
Published: October 2005

Prior to the launch of the Geoscience Laser Altimeter System (GLAS) on the Ice, Cloud and land Elevation Satellite (ICESat) in January 2003, topographic surveys were made by NASA's Airborne Topographic Mapper (ATM) over regions of the western United States and the Antarctic Dry Valleys to support calibration and validation of the range and pointing errors of GLAS lasers. Surveyed areas included terrain with large slopes, allowing pointing‐bias estimation with as little as a few seconds of ICESat data. Range errors over sloping irregular surfaces are calculated by computing the expected GLAS return waveform and comparing it with the actual waveform. We conclude that the range bias is less than 2 cm and that pointing errors for the best available data set (Laser 2a) have rss errors less than 2 arcsec.
Detection of changes in temperature extremes during the second half of the 20th century
Authors: Christidis Nikolaos , Stott Peter A. , Brown Simon , Hegerl Gabriele C. , Caesar John
Published: October 2005

Since 1950, the warmest and coldest days and nights of the year have become warmer. Comparing these observations with climate model simulations in an optimal detection analysis shows a significant human influence on patterns of change in extremely warm nights. Human influence on cold nights and days is also detected, although less robustly, but there is no detection of a significant human influence on extremely warm days. In the future, extreme temperatures are expected to intensify considerably, with adverse consequences for human health.
Temperature difference across the Lomonosov Ridge: Implications for the Atlantic Water circulation in the Arctic Ocean
Authors: Kikuchi Takashi , Inoue Jun , Morison James H.
Published: October 2005

Drifting buoy observations in the Arctic Ocean indicate that, unlike climatological conditions, the temperature of the upper Atlantic water was higher in the Makarov Basin side of the Lomonosov Ridge than in the Amundsen Basin side in 2004. Hydrographic data from 1991 to 2004 has been compared with climatology to examine the relative phase of Atlantic water temperature change in these regions. On the Amundsen Basin side of the Lomonosov Ridge, a positive temperature anomaly in the Atlantic water began in the early 1990s, continued from the mid‐1990s to the early 2000s and started decreasing in 2004. In contrast, positive temperature anomalies were first apparent on the Makarov Basin side of the Lomonosov Ridge in 2000, and continue in 2004. Recent historical data indicates that the arrival of temperature anomalies on the Makarov Basin side of the Lomonosov Ridge is delayed about 7 years after arrival on the Amundsen Basin side. Our results support the idea that Atlantic Water circulates cyclonically around the periphery of the Makarov basin at a propagation speed of 1–2 cm s−1.
Targeted 3‐D prestack depth imaging at Legs 190‐196 ODP drill sites (Nankai Trough, Japan)
Authors: Costa Pisani Patrizia , Reshef Moshe , Moore Gregory
Published: October 2005

Target‐oriented 3‐D prestack depth migration (PSDM), tied to known depths of key reflections at three ODP drill sites in the Nankai Trough, provides an improved representation of the subsurface depths and P‐wave velocities around the drill holes. The resulting velocity volume is representative of the “in situ” velocities and allows us to extend the 1‐D logging and core velocity data from the drill sites to the entire seismic transect. The PSDM velocity gradients closely match those at the drill sites, although the absolute values of the velocity curves are somewhat different. The average PSDM vertical velocity gradient above the décollement decreases from 0.99 s−1 seaward of the trench axis to 0.87 s−1 landward in the proto‐thrust and frontal thrust zone, with a velocity inversion of about 50–150 m/s at the décollement. Below the décollement, the vertical gradient in the underthrusting section decreases from 0.97 s−1 in the basin to 0.72 s−1 beneath the frontal thrust. The lateral velocity gradient in the underthrusting section between the basin and the deformation front is 0.02 s−1, corresponding to ∼10% thinning in the direction of subduction.
Introduction to special section: Coastal Advances in Shelf Transport
Authors: Barth J. A. , Wheeler P. A.
Published: October 2005

The Coastal Ocean Advances in Shelf Transport (COAST) program conducted an interdisciplinary study of coastal upwelling off central Oregon during summer 2001. Two intensive field efforts during May–June and August 2001 were coordinated with ocean circulation, ecosystem, and atmospheric modeling of the region. A primary goal was to contrast the coastal ocean response to wind forcing in a region of relatively simple alongshore bottom topography versus that associated with a substantial submarine bank. In this overview we provide background motivation for the COAST project and summarize the major research findings.
Simulation of the relative impact of land cover and carbon dioxide to climate change from 1700 to 2100
Authors: Lamptey Benjamin L. , Barron Eric J. , Pollard David
Published: October 2005

The contribution of land cover change (relative to increased CO2) to climate change at the global scale is investigated using the Global Environmental and Ecological Simulations of Interactive Systems (GENESIS) climate model with an interactive BIOME vegetation model based on simulations at 1700 and 2100. Three 40‐year model equilibrium simulations were performed. The first experiment specified carbon dioxide levels of 280 ppmv without human‐induced land use (1700); the second experiment specified carbon dioxide levels of 690 ppmv without human‐induced land use; the third experiment specified carbon dioxide levels of 690 ppmv and included patterns of extensive human land use (as projected for 2100). Data on the extent of human modification to the land at different times were obtained from the History Database of the Global Environment (HYDE) for 1700 and the Integrated Model to Assess the Global Environment (IMAGE2.2) for 2100. The IMAGE model projects land cover changes in response to demographic and economic activity. The projection based on the A1b scenario of the Intergovernmental Panel on Climate Change Special Report on Emission Scenarios was used for this work. As expected, statistically significant (95% level) climate changes in response to carbon dioxide levels were widespread. In contrast, the impact of the land cover change appears to reduce the spatial extent and sometimes magnitude of the changes in temperature due to increased carbon dioxide. Regions where land cover change explained more than 60% of the combined signal due to an increase in CO2 and land cover change are confined to the Northern Hemisphere for near‐surface temperature. Projected land cover changes produced warming (but smaller than that produced by CO2) in some regions and cooling in other regions. The warming, which is about 4 K (seasonal) in some mid to high latitudes, is dominated by physiological factors altering the balance of latent to sensible heating rather than morphological mechanisms. The simulated changes in precipitation are more complex.
Caffeic acid phenethyl ester modulatesHelicobacter pylori‐induced nuclear factor‐kappa B and activator protein‐1 expression in gastric epithelial cells
Authors: Abdel‐Latif Mohamed M M , Windle Henry J , Homasany Basma S El , Sabra Kamal , Kelleher Dermot
Published: October 2005

Caffeic acid phenethyl ester (CAPE), an active component of propolis from honeybee hives (honeybee resin), has anti‐inflammatory, anti‐carcinogenic and anti‐bacterial properties. This study was designed to investigate the anti‐inflammatory effects of CAPE onHelicobacter pylori‐induced NF‐κB and AP‐1 in the gastric epithelial cell line AGS.

Electrophoretic mobility shift assay was used to measure NF‐κB‐ and AP‐1‐DNA binding activity. Western blotting was used to detect IκB‐αand COX‐2 expression in AGS cells cocultured withH. pylori. The antiproliferative effect of CAPE was measured by MTT assay.

Our results showed that caffeic phenethyl ester inhibitsH. pylori‐induced NF‐κB and AP‐1 DNA‐binding activity in a dose (0.1–25 μg ml−1∼0.35–88 μM) and time‐ (15–240 min) dependent manner in AGS cells. Maximum inhibition by CAPE was observed at concentrations of 25 μg ml−1(∼88 μM) CAPE preventedH. pylori‐ and cytokine‐induced degradation of IκB‐αprotein.

Pretreatment of AGS cells with CAPE also blocked cytokine‐ and mitogen‐induced NF‐κB and AP‐1 expression. Furthermore, CAPE suppressedH. pylori‐induced cell proliferation and production of the cytokines TNF‐αand IL‐8. In addition, CAPE blockedH. pylori‐induced COX‐2 expression.

The inhibition of such transcription by CAPE could result in suppression of many genes duringH. pylori‐induced inflammation, and also provide new insights into the anti‐cancer and anti‐inflammatory properties of CAPE.

British Journal of Pharmacology(2005)146, 1139–1147. doi:10.1038/sj.bjp.0706421
Feminist ‘Selves’ and Feminism's ‘Others’: Feminist Representations of Jamaat-E-Islami Women in Pakistan
Authors: Jamal Amina
Published: October 2005

In Pakistan, as in many other societies, politico-religious movements or so-called Islamist fundamentalist movements are becoming an important site for women's activism as well as the harnessing of such activism to promote agendas that seem to undermine women's autonomy. This has become a concern for a growing feminist literature which from a variety of political and theoretical positions seeks to understand and explain the subject-position of Muslim women as politico-religious activists. This paper attempts a deconstructive reading of texts by leading Pakistani feminist scholars as they attempt the difficult process of steering between fundamentalism and Orientalism in their accounts of ‘fundamentalist’ women in the political ideological space of Pakistan.
Boundary-layer exchange by bubble: A novel method for generating transient nanofluidic layers
Authors: Jennissen Herbert P.
Published: October 2005

Unstirred layers (i.e., Nernst boundary layers) occur on every dynamic solid-liquid interface, constituting a diffusion barrier, since the velocity of a moving liquid approaches zero at the surface (no slip). If a macromolecule-surface reaction rate is higher than the diffusion rate, the Nernst layer is solute depleted and the reaction rate becomes mass-transport limited. The thickness of a Nernst boundary layer (δN) generally lies between 5 and 50μm. In an evanescent wave rheometer, measuring fibrinogen adsorption to fused silica, we made the fundamental observation that an air bubble preceding the sample through the flow cell abolishes the mass-transport limitation of the Nernst diffusion layer. Instead exponential kinetics are found. Experimental and simulation studies strongly indicate that these results are due to the elimination of the Nernst diffusion layer and its replacement by a dynamic nanofluidic layer (δν) maximally 200–300nm thick. It is suggested that the air bubble leads to a transient boundary-layer separation into a novel nanoboundary layer on the surface and the bulk fluid velocity profile separated by a vortex sheet with an estimated lifetime of 30–60s. A bubble-induced boundary-layer exchange from the Nernst to the nanoboundary layer and back is obtained, giving sufficient time for the measurement of unbiased exponential surface kinetics. Noteworthy is that the nanolayer can exist at all and displays properties such as (i) a long persistence and resistance to dissipation by the bulk liquid (boundary-layer-exchange-hysteresis) and (ii) a lack of solute depletion in spite of boundary-layer separation. The boundary-layer-exchange by bubble (BLEB) method therefore appears ideal for enhancing the rates of all types of diffusion-limited macromolecular reactions on surfaces with contact angles between 0° and 90° and only appears limited by slippage due to nanobubbles or an air gap beneath the nanofluidic layer on very hydrophobic surfaces. The possibility of producing nanoboundary layers without any nanostructuring or nanomachining should also be useful for fundamental physical studies in nanofluidics.
Rigorous dynamics and radiation theory for a Pauli-Fierz model in the ultraviolet limit
Authors: Bertini Massimo , Noja Diego , Posilicano Andrea
Published: October 2005

The present paper is devoted to the detailed study of quantization and evolution of the point limit of the Pauli-Fierz model for a charged oscillator interacting with the electromagnetic field in dipole approximation. In particular, a well defined dynamics is constructed for the classical model, which is subsequently quantized according to the Segal scheme. To this end, the classical model in the point limit, already obtained by Noja and Posilicano [Ann. I.H.P. Phys. Theor. 71, 425 (1999)], is reformulated as a second order abstract wave equation, and a consistent quantum evolution is given. This allows a study of the behavior of the survival and transition amplitudes for the process of decay of the excited states of the charged particle, and the emission of photons in the decay process. In particular, for the survival amplitude the exact time behavior is found. This is completely determined by the resonances of the systems plus a tail term prevailing in the asymptotic, long time regime. Moreover, the survival amplitude exhibits in a fairly clear way the Lamb shift correction to the unperturbed frequencies of the oscillator.
Fast evaluation of polarizable forces
Authors: Wang Wei , Skeel Robert D.
Published: October 2005

Polarizability is considered to be the single most significant development in the next generation of force fields for biomolecular simulations. However, the self-consistent computation of induced atomic dipoles in a polarizable force field is expensive due to the cost of solving a large dense linear system at each step of a simulation. This article introduces methods that reduce the cost of computing the electrostatic energy and force of a polarizable model from about 7.5 times the cost of computing those of a nonpolarizable model to less than twice the cost. This is probably sufficient for the routine use of polarizable forces in biomolecular simulations. The reduction in computing time is achieved by an efficient implementation of the particle-mesh Ewald method, an accurate and robust predictor based on least-squares fitting, and non-stationary iterative methods whose fast convergence is accelerated by a simple preconditioner. Furthermore, with these methods, the self-consistent approach with a larger timestep is shown to be faster than the extended Lagrangian approach. The use of dipole moments from previous timesteps to calculate an accurate initial guess for iterative methods leads to an energy drift, which can be made acceptably small. The use of a zero initial guess does not lead to perceptible energy drift if a reasonably strict convergence criterion for the iteration is imposed.
On the origins of approximations for stochastic chemical kinetics
Authors: Haseltine Eric L. , Rawlings James B.
Published: October 2005

This paper considers the derivation of approximations for stochastic chemical kinetics governed by the discrete master equation. Here, the concepts of (1) partitioning on the basis of fast and slow reactions as opposed to fast and slow species and (2) conditional probability densities are used to derive approximate, partitioned master equations, which are Markovian in nature, from the original master equation. Under different conditions dictated by relaxation time arguments, such approximations give rise to both the equilibrium and hybrid (deterministic or Langevin equations coupled with discrete stochastic simulation) approximations previously reported. In addition, the derivation points out several weaknesses in previous justifications of both the hybrid and equilibrium systems and demonstrates the connection between the original and approximate master equations. Two simple examples illustrate situations in which these two approximate methods are applicable and demonstrate the two methods’ efficiencies.
Efficient method for the calculation of time- and frequency-resolved four-wave mixing signals and its application to photon-echo spectroscopy
Authors: Gelin Maxim F. , Egorova Dassia , Domcke Wolfgang
Published: October 2005

An efficient method has been developed for the calculation of third-order time- and frequency-resolved optical signals. To obtain the general four-wave mixing signal, seven auxiliary density matrices have to be propagated in time. For the special cases of two-pulse photon-echo and transient-grating signals, two or three density matrices, respectively, are required. The method is limited to weak laser fields (it is thus valid within the third-order perturbation theory) but allows for any pulse durations and automatically accounts for pulse-overlap effects. To illustrate the method, we present the explicit derivation of the three-pulse photon-echo signal. Any other third-order optical signal can be calculated in the same manner. As an example, two- and three-pulse photon-echo and transient-grating signals for a weakly damped displaced harmonic oscillator have been calculated.
Analytic structure of radiation boundary kernels for blackhole perturbations
Authors: Lau Stephen R.
Published: October 2005

Exact outer boundary conditions for gravitational perturbations of the Schwarzschild metric feature integral convolution between a time-domain boundary kernel and each radiative mode of the perturbation. For both axial (Regge–Wheeler) and polar (Zerilli) perturbations, we study the Laplace transform of such kernels as an analytic function of (dimensionless) Laplace frequency. We present numerical evidence indicating that each such frequency-domain boundary kernel admits a “sum-of-poles” representation. Our work has been inspired by Alpert, Greengard, and Hagstrom’s analysis of nonreflecting boundary conditions for the ordinary scalar wave equation.
Analysis of the rotational spectrum of methylene (CH2) in its vibronic ground state with an Euler expansion of the Hamiltonian
Authors: Brünken Sandra , Müller Holger S. P. , Lewen Frank , Giesen Thomas F.
Published: October 2005

We present an analysis of a global, field-free data set of the methylene radical CH2 in its X̃B13 vibronic ground state by means of a novel Euler expansion of the Hamiltonian. The data set comprises pure rotational transitions up to 2THz obtained with microwave accuracies of 30–500kHz as well as ν2 ground-state combination differences and pure rotational data obtained with infrared accuracies of 0.001–0.010cm−1. Highly accurate spectroscopic parameters have been determined. These include rotational, spin-spin, spin-rotation, and electron-spin–nuclear-spin coupling terms along with several centrifugal distortion corrections. The spectroscopic model has been tested and improved by recording newly three weak ΔN≠ΔJ fine-structure components of the NKaKc=212−303 and 505−414 transitions near 434, 454, and 581GHz. These lines were rather close to the predictions. Overall weighted root mean squares of 1.28 and 0.83 were achieved for fits in which the Euler expansion was used only for the rotational part of the Hamiltonian or for the rotational and spin-spin terms of the Hamiltonian, respectively. The resulting spectroscopic parameters allow for precise frequency predictions of astrophysically important rotational transitions of methylene.
First-principles investigation of finite-temperature behavior in small sodium clusters
Authors: Lee Mal-Soon , Chacko S. , Kanhere D. G.
Published: October 2005

A systematic and detailed investigation of the finite-temperature behavior of small sodium clusters, Nan, in the size range of n=8–50 are carried out. The simulations are performed using density-functional molecular dynamics with ultrasoft pseudopotentials. A number of thermodynamic indicators such as specific heat, caloric curve, root-mean-square bond-length fluctuation, deviation energy, etc., are calculated for each of the clusters. Size dependence of these indicators reveals several interesting features. The smallest clusters with n=8 and 10 do not show any signature of melting transition. With the increase in size, broad peak in the specific heat is developed, which alternately for larger clusters evolves into a sharper one, indicating a solidlike to liquidlike transition. The melting temperatures show an irregular pattern similar to the experimentally observed one for larger clusters [Schmidt et al., Nature (London) 393, 238 (1998)]. The present calculations also reveal a remarkable size-sensitive effect in the size range of n=40–55. While Na40 and Na55 show well-developed peaks in the specific-heat curve, Na50 cluster exhibits a rather broad peak, indicating a poorly defined melting transition. Such a feature has been experimentally observed for gallium and aluminum clusters [Breaux et al., J. Am. Chem. Soc. 126, 8628 (2004); Breaux et al., Phys. Rev. Lett. 94, 173401 (2005)].
State-to-state photodissociation of carbonyl sulfide (ν2=,1∣JlM). II. The effect of initial bending on coherence of S(D21) polarization
Authors: van den Brom Alrik J. , Rakitzis T. Peter , Janssen Maurice H. M.
Published: October 2005

Photodissociation studies using ion imaging are reported, measuring the coherence of the polarization of the S(D21) fragment from the photolysis of single-quantum state-selected carbonyl sulfide (OCS) at 223 and 230nm. A hexapole state-selector focuses a molecular beam of OCS parent molecules in the ground state (ν2=0∣JM=10) or in the first excited bending state (ν2=1∣JlM=111). At 230nm photolysis the Im[a1(1)(‖,⊥)] moment for the fast S(D21) channel increases by about 50% when the initial OCS parent state changes from the vibrationless ground state to the first excited bending state. No dependence on the initial bending state is found for photolysis at 223nm. We observe separate rings in the slow channel of the velocity distribution of S(D21) correlating to single CO(J) rotational states. The additional available energy for photolysis at 223nm is found to be channeled mostly into the CO(J) rotational motion. An improved value for the OC–S bond energy D0=4.292eV is reported.
Comment on “Hydrophobic effects on partial molar volume” [J. Chem. Phys. 122, 094509 (2005)]
Authors: Graziano Giuseppe
Published: October 2005

It is pointed out that the results obtained by Imai and Hirata [ J. Chem. Phys.122, 094509 (2005)] for the partial molar volume of benzene in a detailed model of water and in a hypothetical nonpolar water model should be interpreted with care. By turning off the electrostatic interactions among water molecules, keeping fixed the molar volume and so the liquid number density, in order to produce the hypothetical nonpolar water without H bonds, the size of water molecules increases from about 2.8 to about 3.2Å. This fact is due to the bunching-up effect of H bonds. The consequences of this fact are clarified by means of calculations performed using the analytical expression of the partial molar volume derived by Lee [J. Phys. Chem.87, 112 (1983)] from the scaled particle theory equation of state for hard-sphere mixtures.
Instrument techniques for rheometry
Authors: Hou Ying Y. , Kassim Hamida O.
Published: October 2005

This article presents a review of some latest advances in rheology measuring techniques. Consideration is given to the modification and approaches in conventional measuring techniques and also to the development of specialty instruments. A number of sensing technologies such as nuclear-magnetic-resonance imaging and ultrasonic pulse Doppler mapping have recently been adopted to produce viscoelastic measurements for both Newtonian and non-Newtonian materials. The working principles of these technologies and their applications are described. Other recent developments in modifications of conventional rheometers for performance enhancement and for complex material characterizations have been thoroughly discussed. Some instrument designs and their special applications, such as interfacial rheometers, extensional rheometers, and high-pressure rheometers, have also been evaluated in detail.
Rotational diffusion of colloidal particles near confining walls
Authors: Jones R. B.
Published: October 2005

We study the rotational diffusion of a spherical colloid confined in a narrow channel between parallel plane hard walls. The walls damp translational diffusion much more than rotational diffusion so that there is expected to be little translation-rotation coupling. Using a recent calculation of the nonisotropic rotational mobilities arising from the hydrodynamic interactions with the walls, we set up the rotational Smoluchowski equation for either a particle with a permanent dipole moment or a polarizable particle with axisymmetric polarizabilities subject to an external electric field. Using the Smoluchowski equation dynamics we calculate the time-correlation functions of orientation that are measured in depolarized light scattering for the cases of no external field, external field normal to the walls, and external field parallel to the walls. The decay of correlations is shown to be given by a weighted sum of decaying exponentials and can be characterized by an initial and a mean characteristic decay time. The weights and decay rates of each component and the characteristic decay times are studied numerically for a range of field strengths. The nonisotropic rotational mobilities make these decay times highly sensitive to the distance of the particle from the confining walls. This position dependence can be used as a method of measuring the rotational mobilities or, conversely, the rate of decay of correlations can be used as a probe of particle position between the confining walls.
Effects of Ca doping on the Curie temperature, structural, dielectric, and elastic properties of Ba0.4Sr0.6−xCaxTiO3 (0⩽x⩽0.3) perovskites
Authors: Zheng R. K. , Wang J. , Tang X. G. , Wang Y. , Chan H. L. W. , Choy C. L. , Li X. G.
Published: October 2005

The effects of Ca doping on the Curie temperature, structural, dielectric, and elastic properties of Ba0.4Sr0.6−xCaxTiO3 (0⩽x⩽0.3) has been studied. Powder x-ray diffraction revealed that the cubic lattice constant a decreases linearly with increasing x from 0 to 0.15, while showing an anomalous expansion between x=0.15 and x=0.18. This, together with the anomalies in the dielectric constants, Curie temperature TC, and elastic constants observed for 0.15<x<0.18, suggests that a small amount of Ca ions substituted for Ti ions. Correlated with the evolution of a with x, TC increases linearly with increasing x from 0 to 0.15; while deviating from linear behavior for x>0.15, TC increases persistently up to x=0.25 and thereafter shows a decrease. These variations of TC with x have been interpreted in terms of Ca-doping-induced A-site cation size variance, a substitution of a small amount of Ca ions for Ti ions, and structural phase separation. Upon cooling the longitudinal elastic constant CL shows drastic softening near TC, arising from the electrostrictive coupling between the polarization fluctuations and the elastic strains. Moreover, it was found that Ca doping induces the hardening of CL just below TC, and the magnitude of the relative hardening of CL (i.e., ΔCL∕CL) increases with increasing x, implying that the tetragonal ferroelectric phase was increasingly stabilized by Ca doping.
Near-infrared photoconductive and photovoltaic devices using single-wall carbon nanotubes in conductive polymer films
Authors: Kazaoui S. , Minami N. , Nalini B. , Kim Y. , Hara K.
Published: October 2005

We have fabricated prototypical Al/single-wall carbon nanotube (SWNT)-polymer/indium tin oxide thin-film devices that exhibit promising photoconductive and photovoltaic responses in a broad spectral range, typically from 300to1600nm. This achievement was made possible by finely dispersed SWNT powders in polymer matrices such as poly-phenylene-vinylene and poly-thiophene. These devices utilize (i) the intrinsic near-infrared light harvesting properties of semiconducting SWNTs, (ii) the electronic transport properties of both semiconducting and metallic SWNTs in combination with those of the polymer matrices, and (iii) probably charge/energy transfer processes between SWNTs and the polymers. By selecting different sources of SWNTs and polymers, we have shown that the optoelectronic properties of these devices are potentially tunable. To support our investigation, several techniques including spectrally resolved photoconductivity, optical absorption, and photoluminescence spectroscopy were utilized.
Low-temperature pathways to Ge-rich Si1−xGex alloys via single-source hydride chemistry
Authors: Hu C.-W. , Menéndez J. , Tsong I. S. T. , Tolle J. , Chizmeshya A. V. G. , Ritter Cole , Kouvetakis J.
Published: October 2005

We report rapid low-temperature (300–470°C) growth of Si0.50Ge0.50, Si0.33Ge0.67, Si0.25Ge0.75, and Si0.20Ge0.80 alloys on Si(100) using heavy single-source hydride molecular compounds (H3Ge)nSiH4−n (n=1–4). Incorporation of the entire SiGe, SiGe2, SiGe3, and SiGe4 framework of these precursors into the film provides precise control of morphology, composition, and strain. Low-energy electron microscopy analysis indicates that the (H3Ge)xSiH4−x (x=2–4) species are highly reactive, with H2 desorption characteristics comparable to those of Ge2H6, despite the presence of strong Si–H bonds in their molecular structure.
Controlled enhancement of the electron field-effect mobility of F16CuPc thin-film transistors by use of functionalized SiO2 substrates
Authors: de Oteyza Dimas G. , Barrena Esther , Ossó J. Oriol , Dosch Helmut , Meyer Stephan , Pflaum Jens
Published: October 2005

We present a comparative study of copper-hexadecafluorophthalocyanine (F16CuPc) films grown on bare SiO2 and on SiO2 functionalized by octadecyltrimethoxisilane (OTMS), a methyl terminated molecular layer with a lower surface energy than SiO2. We show that the functionalization of SiO2 by OTMS leads to the formation of highly structurally ordered F16CuPc crystallites. The extended lateral order and subsequent reduction of grain boundaries result in an improved field-effect mobility for electrons by almost an order of magnitude in thin-film transistors made of these films.
Formation of misfit dislocations at the thin strained Si∕strain-relaxed buffer interface
Authors: Loo Roger , Delhougne Romain , Caymax Matty , Ries Mike
Published: October 2005

Misfit dislocations at the strained Si∕SiGe strain-relaxed buffer interface are known to enhance leakage currents of strained Si metal oxide semiconductor devices. As we show in this letter, misfit dislocations at this interface might be generated even for Si thicknesses below the critical thickness for layer relaxation. The important parameter is the degree of relaxation of the strain-relaxed buffer. If the strain-relaxed buffer is not fully relaxed, threading dislocations can glide during thermal treatments. This results in misfit dislocations at the strained Si∕SiGe interface, because the threading dislocation segments within the strained Si are blocked by its tensile stress.
Spatial resolution of ballistic electron emission microscopy measured on metal/quantum-well Schottky contacts
Authors: Tivarus C. , Pelz J. P. , Hudait M. K. , Ringel S. A.
Published: October 2005

Au Schottky contacts on cleaved AlGaAs∕GaAs∕AlGaAs quantum wells (QWs) were used as precise nanometer-scale apertures to quantify the spatial resolution of ballistic electron emission microscopy (BEEM). Both the amplitude and width of the measured average BEEM current profiles showed systematic dependencies on the QW width and Au film thickness, indicating surprisingly large BEEM resolutions of ∼12, ∼16, and ∼22nm for Au film thicknesses of 4, 7, and 15nm, respectively, but roughly independent of Au grain size. These measurements are consistent with theoretical models that include multiple hot-electron scattering at interfaces and in the bulk of the metal film.
Programmable logic elements based on ferromagnetic nanodisks containing two antidots
Authors: Rahm M. , Stahl J. , Weiss D.
Published: October 2005

Magnetoresistive elements for data storage or logic operations require reliable bistable magnetic switching. Soft magnetic nanodisks containing two antidots, which serve as pinning sites for a magnetic vortex, provide an alternative route for bistable magnetic switching. Here we show by means of micromagnetic simulations that field pulses generated by two orthogonal metallic current lines can switch the magnetic vortex core between antidots on a subnanosecond time scale. Using a third strip line to enable switching of the element’s magnetically hard layer, the logic operations AND, OR, NAND, and NOR can be established.
Atomic scale morphology of thin GaNAs films: Effects of nitrogen content and growth temperature
Authors: McGee W. M. , Bone P. A. , Williams R. S. , Jones T. S.
Published: October 2005

The surface morphology of 8nm GaNAs layers grown by molecular-beam epitaxy on GaAs(001) substrates has been studied as a function of nitrogen content and growth temperature using scanning tunneling microscopy (STM). Increasing the nitrogen content from 0%–3% leads to a pronounced increase in surface roughness, caused by the appearance of deep pits. Raising the growth temperature from 400–500°C produces the same effect. We propose that pit formation is symptomatic of phase segregation. STM images show that the GaNAs layers adopt an (n×3) surface reconstruction, suggesting that a disproportionately high concentration of N is present on the postgrowth surface compared with that incorporated into the layer during growth.
Room-temperature single-electron effects in silicon nanocrystal memories
Authors: Pace C. , Crupi F. , Lombardo S. , Gerardi C. , Cocorullo G.
Published: October 2005

In this work, we present an experimental study on the single-electron effects observed at room temperature in silicon nanocrystal memories. The electrical characterization has been performed by means of a purposely designed low noise high bandwidth measurement system. Relevant statistical properties of the threshold voltage shifts induced by single-electron trapping and detrapping in the silicon dots are reported. The kinetics of electron capture and emission is also discussed.
Subpicosecond saturation of intersubband absorption in (CdS∕ZnSe)∕BeTe quantum-well waveguides at telecommunication wavelength
Authors: Akimoto R. , Li B. S. , Akita K. , Hasama T.
Published: October 2005

Ultrafast all-optical switching at an optical communication wavelength has been investigated by utilizing an intersubband transition (ISBT) of II–VI-based multiple quantum wells (MQWs) fabricated in high-mesa waveguide devices. The waveguide structure consists of a CdS∕ZnSe∕BeTe MQW core layer and two top and bottom ZnMgBeSe quaternary cladding layers grown by molecular beam epitaxy on a (001) GaAs substrate. A marked increase in waveguide transmittance was observed only for transverse-magnetic-polarized subpicosecond pulse with increasing incident pulse energy at λ=1.57μm, indicative of the ISBT absorption saturation. The pulse energy necessary for a 10dB transmittance increase is as low as 13.3pJ for a waveguide device with 2.7μm mesa, and the saturation pulse energy can be even further reduced by employing a narrower mesa structure. Ultrafast gate switching within a time window of 0.56ps was also demonstrated with pump pulse at λ=1.57μm and probe pulse at λ=1.63μm in this waveguide device.
Third-order nonlinear optical properties of a cadmiun sulfide-dendrimer nanocomposite
Authors: Etienne Michael , Biney Anna , Walser Ardie D. , Dorsinville Roger , Bauer David L. V. , Balogh-Nair Valeria
Published: October 2005

We have investigated the nonlinear optical response of thin films consisting of a poly(propyleneimine) dendrimer matrix having diaminobutane core with and without small 2.2nm diameter CdS quantum dots. Large nonlinear coefficients and low nonlinear absorption losses were observed at 532 and 1064nm. The high nonlinearity and low two-photon absorption yielded promising figures of merit for nonlinear optical switching applications.
Coordination-complex polymer as an organic conductor for organic light-emitting diodes
Authors: Seo Soon-Min , Kim Joon H. , Park Jeong-Yong , Lee Hong H.
Published: October 2005

A coordination complex of poly(3,4-ethylene dioxythiophene)-poly(styrene sulfonate) (PEDOT-PSS) is used to enhance the performance of organic light-emitting diodes. Use of the coordination complex formed by copper results in more than doubling the device lifetime when the complex is used as the hole injection layer (HIL) in place of the usual HIL of PEDOT-PSS that is not treated. Of the possible coordination complexes of PEDOT-PSS, the coordination complex formed with copper gives the best performance. The optimal mass ratio of CuSO4 and PEDOT-PSS solution in forming the complex is found to be 0.533. Surface morphology of the organic film formed and conductivity enhancement are the main factors that determine the optimal mass ratio.
Photoinduced stress in a ZnSe∕GaAs epilayer containing 90°α partial dislocations
Authors: Ohno Yutaka
Published: October 2005

Photoinduced stress in a ZnSe∕GaAs epilayer containing 90°α partial dislocations was observed in situ by means of polarized cathodoluminescence spectroscopy under light illumination in a transmission electron microscope. A dislocation glided under the illumination of a monochromatic light whose photon energy was above 2.07–2.40eV, presumably due to a recombination-enhanced effect. The glide accompanied with a variation of the compression stress along [110] in the epilayer; the stress decreased at the temperature of 35K, while it increased at higher temperatures.
Fabrication and application of long strands of silicon nanowires as sensors for bovine serum albumin detection
Authors: Shao Ming-Wang , Yao Hui , Zhang Ming-Liang , Wong Ning-Bew , Shan Yue-Yue , Lee Shuit-Tong
Published: October 2005

Strands of aligned silicon nanowires (SiNWs) with lengths over 2mm and diameters of 35nm were synthesized via a two-step controlled growth. The large dimensionality made it possible to fabricate an individual strand of SiNWs into an electrode for cyclic voltammetric detection of bovine serum albumin (BSA). The strand sensor with the immense surface area and electrical conductivity of SiNWs shows the highest sensitivity and widest linear range ever reported for BSA detection.
Growth mechanism of stacked-cone and smooth-surface GaN nanowires
Authors: Cai X. M. , Djurišić A. B. , Xie M. H. , Chiu C. S. , Gwo S.
Published: October 2005

Gallium nitride (GaN) nanowires were grown on uncoated or Ni-coated Si substrates by evaporation of Ga in NH3∕Ar gas flow. A mixture of nanowires growing along [101¯0] and [0001] was obtained, where the former showed smooth surfaces and the latter showed the stacked-cone morphology. The yield of the two types of nanowires was found to depend on the NH3 flow. The reduction of NH3 flow led to fewer stacked-cone nanowires. The growth mechanisms of the two types of GaN nanowires are discussed.
The Financial Economics of Privatization
Authors: Megginson William Leon
Published: October 2005

This book explores the different aspects of privatization. It charts the emergence of privatization and looks at how and why countries privatize their state-owned enterprises (SOEs). It examines the impact of privatization on financial markets, and transition and nontransition economies. It analyzes the privatization experiences of five industries that have seen the largest number of state ownership sales: telecommunications, banking, oil and gas, electricity production and distribution, and commercial airlines. The key lessons of privatization based on experience and empirical research as well as unresolved issues in privatization policy and research are discussed.
The Scope of Privatization
Authors: Megginson William Leon
Published: October 2005

This chapter begins with a discussion of the history of state ownership. It then charts the rise of privatization programs since these were first popularized by Margaret Thatcher’s Conservative British government in the early 1980s. An overview of chapters included in this volume is presented.
Privatization Industry Studies
Authors: Megginson William Leon
Published: October 2005

This chapter examines why governments are choosing to privatize state-owned banks (SOBs), how they are selling SOBs, and whether these sales have achieved the goals set by the divesting governments. The overall impact of state ownership of banks has been disastrous in almost every country. Reducing state influence on credit allocation decisions is essential for countries seeking to establish a more efficient and market-oriented economy. Privatizing governments should completely divest their ownership in banks whenever and wherever it is politically feasible to do so. Privatization is also associated with performance improvements in divested banks, though the extent of improvement varies by region and stage of national development.
The Lessons and Future of Privatization
Authors: Megginson William Leon
Published: October 2005

This chapter begins with a discussion of the lessons learned from a quarter-century of privatization. It then considers the unresolved issues in privatization policy and research. It concludes with an assessment of likely future course of privatization in the short, medium, and long term.