bluuebunny/crossref_metadata_2025 huggingface dataset:
Reaktives Magnetronsputtern von Dünnschichtsolarzellen
Authors: Ellmer Klaus , Unold Thomas
Published: September 2006

Es wird gezeigt, dass reaktives Magnetronsputtern geeignet ist, um elektronisch hochwertige CuInS2‐Solarzellen‐Absorberschichten herzustellen. Hierbei können die Schichten mit einer kompakten Morphologie und Korngrößen im Mikrometerbereich bei Substrattemperaturen unter 500 °C mit Hilfe von metallischen Targets abgeschieden werden. Die mit diesem Prozess hergestellten Schichten besitzen vergleichbare strukturelle und elektronische Eigenschaften, wie CuInS2‐Schichten die in einem 2‐Stufen‐Sulfurisierungsprozess präpariert werden, welcher zur Zeit kommerzialisiert wird. Insbesondere lassen sich für die reaktiv gesputterten Schichten Ladungsträger‐Diffusionslängen von der Größenordnung der Schichtdicke (≈ 2μm) nachweisen. Dies resultiert in Solarzellen mit Wirkungsgraden größer 10 %, vergleichbar mit den besten Wirkungsgraden von CuInS2‐Solarzellen aus anderen Beschichtungsprozessen. Diese Ergebnisse sind vielversprechend im Hinblick auf die Entwicklung des Magnetronsputterns als Großflächenbeschichtungsverfahren für Absorberschichten in Dünnschicht‐Solarzellen.
Optische und mechanische Eigenschaften von RLVIP HfO2‐Schichten
Authors: Kunz Andrea , Hallbauer Antje , Huber Daniel , Pulker Hans K.
Published: September 2006

In diesem Artikel wurden auf ungeheizten Gläsern (Quarzglas, Borosilikatglas) und Si‐Wafern HfO2‐Schichten mittels Reaktiven Niederspannungs‐Hochstrom‐Ionenplattieren (RLVIP) hergestellt. Diese wurden hinsichtlich der optischen Eigenschaften (Brechungsindex, Absorptionskoeffizient) und den mechanischen Schichtspannungen untersucht. Hierfür wurden die Prozessparameter Bogenstrom und Sauerstoffpartialdruck variiert. Mit dem Spektralphotometer wurde die Transmission der Schichten vermessen, woraus der Brechungsindex und die Absorptionskante ermittelt wurden. Für die Messung der Absorption wurde die Photothermale Deflektionsspektroskopie eingesetzt und der Absorptionskoeffizient berechnet. Die mechanischen Schichtspannungen wurden aus der Verformung von dünnen Si‐Wafern ermittelt.
A load awareness medium access control protocol for single‐hop wireless ad hoc networks
Authors: Chao Chih‐Min , Sheu Jang‐Ping , Chou I‐Cheng
Published: September 2006

A contention‐based wireless ad hoc medium access control (MAC) protocol, such as carrier sense multiple access with collision avoidance (CSMA/CA), has excellent efficiency when the system is light loaded. The main drawback of such protocols is their inefficiency and unbounded delay when the system load is heavy. On the other hand, a contention‐free MAC protocol, such as token passing, has a better and fair throughput when the system is heavy loaded. The main drawback of such protocols is their inefficiency when only a small amount of users want to transmit. In this paper, we propose a new load awareness single‐hop wireless ad hoc MAC protocol (which is called theLAprotocol) that exploits the benefits of both contention‐based and contention‐free protocols. A contention‐based MAC protocol is used when the system is light loaded and a contention‐free one is used otherwise. OurLAprotocol, which operates in a distributed fashion and is fully compatible with the IEEE 802.11 wireless local area network (WLAN) standard, can switch smoothly between the contention‐based protocol and the contention‐free one. Simulation results show that our protocol indeed extracts the better part of two kinds of protocols. Copyright © 2006 John Wiley & Sons, Ltd.
The Effects of Cumulative Risks and Promotive Factors on Urban Adolescent Alcohol and Other Drug Use: A Longitudinal Study of Resiliency
Authors: Ostaszewski Krzysztof , Zimmerman Marc A.
Published: September 2006

Resiliency theory provides a conceptual framework for studying why some youth exposed to risk factors do not develop the negative behaviors they predict. The purpose of this study was to test compensatory and protective models of resiliency in a longitudinal sample of urban adolescents (80% African American). The data were from Years 1 (9th grade) and 4 (12th grade). The study examined effects of cumulative risk and promotive factors on adolescent polydrug use including alcohol, tobacco and marijuana. Cumulative measures of risk/promotive factors represented individual characteristics, peer influence, and parental/familial influences. After controlling for demographics, results of multiple regression of polydrug use support the compensatory model of resiliency both cross‐sectionally and longitudinally. Promotive factors were also found to have compensatory effects on change in adolescent polydrug use. The protective model of resiliency evidenced cross‐sectionally was not supported in longitudinal analysis. The findings support resiliency theory and the use of cumulative risk/promotive measures in resiliency research. Implications focused on utilizing multiple assets and resources in prevention programming are discussed.
Do seasonally fluctuating aquatic subsidies influence the distribution pattern of birds between riparian and upland forests?
Authors: Uesugi Akane , Murakami Masashi
Published: September 2006

Seasonal fluctuation of allochthonous subsidies influences food web structure and dynamics in recipient communities. This study investigated whether aquatic subsidies influence the dynamics of insectivorous birds in entire catchment. We estimated the prey biomass and bird density in riparian and upland habitats in three catchments in temperate deciduous forests in Hokkaido, Japan. Aquatic prey was found only in riparian forests and the biomass peaked in early spring, while terrestrial prey was equally distributed between habitats and increased in biomass in late spring. Bird density was higher in riparian than in upland forests before bud break, when the biomass of aquatic insects peaked, but was similar in both forests during the rest of the seasons. These results suggest that aquatic prey subsidies are used not only by birds inhabiting riparian forests, but also by birds associated with upland forests. Aquatic prey subsidies may be particularly important in the spring as a critical food resource for survival and the breeding activities of birds, thereby, influencing the population dynamics of bird communities.
Temperature dependent optical properties of single, hierarchically self-assembled GaAs/AlGaAs quantum dots
Authors: Benyoucef M , Rastelli A , Schmidt OG , Ulrich SM , Michler P
Published: September 2006

We report on the experimental observation of bright photoluminescence emission at room temperature from single unstrained GaAs quantum dots (QDs). The linewidth of a single-QD ground-state emission (≈ 8.5 meV) is comparable to the ensemble inhomogeneous broadening (≈ 12.4 meV). At low temperature (T ≤ 40 K) photon correlation measurements under continuous wave excitation show nearly perfect single-photon emission from a single GaAs QD and reveal the single photon nature of the emitted light up to 77 K. The QD emission energies, homogeneous linewidths and the thermally activated behavior as a function of temperature are discussed.
Traveling waves with paraboloid like interfaces for balanced bistable dynamics
Authors: Guo Jong-Shenq , Hamel François , Ninomiya Hirokazu , Roquejoffre Jean-Michel , Chen Xinfu
Published: September 2006

Cylindrically symmetric traveling waves with paraboloid like interfaces are constructed for reaction–diffusion equations with balanced bistable nonlinearities. It is shown that the interface (a level set) is asymptotically a paraboloid

z = \frac{c}{2(n−1)}|x|^{2}

, where

(x,z) \in \mathbb{R}^{n} \times \mathbb{R}

(

n⩾2

) is the space variable and

c

is the speed that the wave travels upwards in the vertical

z

-direction. In the two-dimensional case (i.e.,

n = 1

), the interface is asymptotically a hyperbolic cosine curve

z = A\mathrm{\cosh }(\mu x)

for some positive constants

A

and

μ

.

Nous montrons l'existence d'ondes progressives à symétrie cylindrique pour des équations de réaction–diffusion dont le terme de réaction est une fonction bistable de moyenne nulle. Les courbes de niveau sont de forme parabolique (ou expontielle en dimension 2 d'espace). Plus précisément, l'interface (n'importe quelle courbe de niveau) se comporte asymptotiquement comme une parabole

z = \frac{c}{2(n−1)}|x|^{2}

, où

(x,z) \in \mathbb{R}^{n} \times \mathbb{R}

(

n⩾2

) est la variable d'espace et

c

est la vitesse de propagation de l'onde dans la direction

z

. En dimension 2 d'espace (i.e.

n = 1

), l'interface se comporte asymptotiquement comme un cosinus hyperbolique

z = A\mathrm{\cosh }(\mu x)

, où

A

et

μ

sont des constantes strictement positives.
Interior estimates for some semilinear elliptic problem with critical nonlinearity
Authors: Esposito Pierpaolo
Published: September 2006

We study compactness properties for solutions of a semilinear elliptic equation with critical nonlinearity. For high dimensions, we are able to show that any solutions sequence with uniformly bounded energy is uniformly bounded in the interior of the domain. In particular, singularly perturbed Neumann equations admit pointwise concentration phenomena only at the boundary.

On étudie les propriétés de compacité pour solutions d'une équation elliptique semi-linéaire avec non-linéarité critique. En hautes dimensions, on démontre qu'une suite de solutions avec énergie uniformément bornée est uniformément bornée dans l'intérieur du domaine. En particulier, les équations de Neumann perturbées singulièrement peuvent avoir des phénomènes de concentration seulement sur la frontière.
Childhood adversities and risk for suicidal ideation and attempts: a longitudinal population-based study
Authors: ENNS MURRAY W. , COX BRIAN J. , AFIFI TRACIE O. , DE GRAAF RON , TEN HAVE MARGREET , SAREEN JITENDER
Published: September 2006

Background. Developmental adversities may be risk factors for adult suicidal behavior, but this relationship has rarely been studied prospectively. The present study examined the association between childhood adversities and new onset suicidal ideation and attempts in an adult population-based sample.

Method. The study used a large community mental health survey (the Netherlands Mental Health Survey and Incidence Study; n=7076, age range 18–64 years). Logistic regression analyses were used to evaluate the relationship between childhood adversities and new onset of suicidal ideation and attempts over 3 years of longitudinal follow-up.

Results. During the study period 85 new cases of suicidal ideation and 39 new onset suicide attempts were observed. The incidence rate for new suicide ideation was 0·67% per year and the incidence rate for new suicide attempts was 0·28% per year. Childhood neglect, psychological abuse and physical abuse were strongly associated with new onset suicidal ideation and suicide attempts. Odds ratios (ORs) ranged from 2·80 to 4·66 for new onset suicidal ideation and from 3·60 to 5·43 for new onset suicide attempts. The total number of adversities reported had a strong graded relationship to new onset suicidal ideation and attempts. These associations remained significant after controlling for the effects of mental disorders.

Conclusions. Childhood abuse and multiple adversities are strongly associated with future suicidal behavior and the mental disorders assessed in the present study do not fully account for this effect. A comprehensive understanding of suicidal behavior must take childhood adversities into account.
Obsessive–compulsive disorder, tics and anxiety in 6-year-old twins
Authors: BOLTON DEREK , RIJSDIJK FRÜHLING , O'CONNOR THOMAS G. , PERRIN SEAN , ELEY THALIA C.
Published: September 2006

Background. Previous reports of genetic influences on obsessive–compulsive disorder (OCD) symptoms have suggested moderate heritability. Family history studies of co-morbidity have found familial aggregation with tics, especially for early-onset OCD, and familial aggregation with anxiety disorders.

Method. Heritability of OCD and familial aggregation of OCD, tics and anxiety disorders were investigated in a community sample of 6-year-old twins using a two-phase design in which 4662 twin pairs were sampled and 854 pairs were assessed in the second phase by maternal-informant diagnostic interview using DSM-IV criteria.

Results. In the multivariate model combined additive genetic and common environmental effects were estimated as 47% for sub-threshold OCD, and the model was unable to distinguish these sources of familial aggregation. There were strong familial aggregations between sub-threshold OCD and tics and between sub-threshold OCD and other anxiety disorders (80% and 97% respectively), although again specific sources could not be distinguished.

Conclusions. The findings are consistent with the hypothesis of a tic-related early-onset OCD phenotype, but also with the hypothesis of an anxiety-related early-onset OCD phenotype.
The use of complementary and alternative medicine in the general population: results from a longitudinal community study
Authors: RÖSSLER WULF , LAUBER CHRISTOPH , ANGST JULES , HAKER HELENE , GAMMA ALEX , EICH DOMINIQUE , KESSLER RONALD C. , AJDACIC-GROSS VLADETA
Published: September 2006

Background.Many patients with psychological or physical problems are interested in non-medical approaches. The reasons for the growing popularity of complementary and alternative medicine (CAM) are not well understood considering that evidence of the effectiveness of conventional therapies is greater than ever before. We have examined data from the Zurich Study to determine trends and predictors of CAM use in Switzerland.

Method.The Zurich Study is a longitudinal community study that was started in 1979 with a sample of 591 participants born in 1958 and 1959. In 1999, the last of six interview waves with face-to-face interviews was conducted. CAM use was analyzed with data from interviews in 1993 and 1999. Polytomous logistic regression analysis focused on the personal, demographic and sociocultural background of CAM users.

Results.CAM use in the last 12 months was reported by 21·9% of the participants in 1993 and by 29·5% in 1999. CAM use among those exhibiting either physical or psychological problems was in the ratio of two to one. There was a trend from alternative variants of CAM (homeopathy) to complementary ones (massage, osteopathy, acupuncture). The vast majority of CAM use was in addition to conventional therapies. Predictors of CAM use were, among others, attribution of physical complaints to stress and other psychological variables, very low education level in parents, and lacking political interest.

Conclusions.Besides the sociocultural background, characteristics such as the psychological attribution style play an important role in CAM use. CAM use in Switzerland is mainly of a complementary rather than an alternative nature.
Hepatitis A virus infection in people of South Asian origin in England and Wales: analysis of laboratory reports between 1992 and 2004
Authors: GUNGABISSOON U. , ANDREWS N. , CROWCROFT N. S.
Published: September 2006

The aim of the study was to determine whether rates of hepatitis A infection are higher in people of South Asian origin compared to the general population, to look for evidence of spread to the general population, and to identify ways to improve preventive strategies. Routine laboratory reports of hepatitis A infection in England and Wales in 1992–2004 were analysed. Study participants were patients with confirmed hepatitis A infection reported to the Health Protection Agency by the diagnosing laboratory. Nam Pehchan software was used to identify patients of South Asian ethnicity. Main outcome measures were comparison of incidence of hepatitis A in South Asian and non-South Asian groups, by age and region. Rates of infection were significantly higher in the South Asian group compared to the non-South Asian group (rate ratio 2·68, 95% confidence interval 2·07–3·47). Patients in the South Asian group had a younger age distribution. Travel was an important risk factor with 85% of those of South Asian origin acquiring their infection abroad, most frequently in the Indian subcontinent, compared to less than one third of those in other groups. Health-care professionals should ensure that all travellers to high-risk countries are protected by hepatitis A vaccination. Targeted information campaigns may be indicated in regions of the United Kingdom for people in South Asian minority ethnic groups.
Some Observations on the Role of Ducats in the Balkans in Late Medieval and Modern Times
Authors: BRZIĆ ALEKSANDAR N.
Published: September 2006

Ducats were issued for the first time in the second half of the thirteenth century. Although practically invisible in Western Europe nowadays, they are still hoarded and used by the rural population of the Balkans. The wealth stored in them is considerable; its level does not show signs of structural decline yet, even in the age of the almighty euro. The history of the use of ducats in the Balkans can be divided into three distinctive periods. Using a descriptive economic-historical approach, the characteristics of these periods, their main evolutionary aspects and particularities are being observed and explained. An overview of countries issuing ducats in the Balkans is given and some economic comparisons used to illustrate the significance of ducats as an economic phenomenon. Finally, the very important question of the use of ducats in jewelry in the Balkans is considered.
‘Putting Animals into Politics’: The Labour Party and Hunting in the First Half of the Twentieth Century
Authors: TICHELAR MICHAEL
Published: September 2006

This article will discuss the background to opposition to hunting within the Labour Party before the Second World War, and in particular the role of the Humanitarian League and its successor the League Against Cruel Sports. It will highlight internal tensions of class and ideology that are still current today. It will examine the fate of two private members bills introduced in 1949 designed to prohibit hunting and coursing. Both bills were heavily defeated after the intervention of the Labour Government. This article will examine the reasons the post-war Labour Government used to oppose the bills before drawing some general conclusions about the Labour movement and blood sports. It will be argued that the primary reason why the bills were defeated was the strong desire of the Government to preserve its relationship with the farmers and the wider rural community.
Non-pharmacological management of orthostatic hypotension in the elderly patient
Authors: Fan Chie Wei , Cunningham Conal J
Published: September 2006

Orthostatic hypotension (OH) is defined as a systolic blood pressure (SBP) drop of at least 20 mmHg, or a diastolic blood pressure drop of at least 10 mm Hg within three minutes of standing from a supine position. It can be symptomatic or asymptomatic and is a common condition that can affect up to one in three older people living in the community. The prevalence is higher amongst those with Parkinson's disease and, unsurprisingly, amongst those attending a syncope clinic. The aetiology and pathophysiology of OH have been comprehensively discussed in a previous article in this journal.
Inner shelf response to Tropical Storm Floyd
Authors: Kohut Josh T. , Glenn Scott M. , Paduan Jeffrey D.
Published: September 2006

A continuously operated coastal observatory off the southern coast of New Jersey provides an opportunity to study both long‐term trends and episodic events. On the evening of 16 September 1999, Tropical Storm Floyd moved up the New Jersey coast directly over the observatory. The response of the inner shelf is characterized using a depth‐averaged (DA) and surface layer (SL) model in conjunction with direct observations. During the storm, the DA model was more representative of the observed response. While there was a peak in the near‐inertial band of the depth average current, the response was not the typical clockwise ringing response seen in deepwater stratified regions. Instead the shallow, well‐mixed inner shelf responded with an alongshore current oscillation balanced by the alongshore pressure gradient and bottom stress. The increased influence of bottom friction damps the typical inertial tail seen in deeper ocean responses and shortens the relaxation phase from several days to hours. Immediately following the storm, the surface layer model better represents the observed currents. It appears that the excessive rainfall associated with the storm and the resulting freshening of the inner shelf isolate the surface layer from the effect of bottom friction. The large waves and currents associated with the storm increase the potential for a sediment resuspension and transport event. Unlike the typical nor'easter in which the transport in this location is alongshore toward the south and onshore, the currents coinciding with the largest waves are alongshore toward the south but with an offshore component.
Stable isotope discrimination during soil denitrification: Production and consumption of nitrous oxide
Authors: Menyailo Oleg V. , Hungate Bruce A.
Published: September 2006

Measuring the stable isotope composition of nitrous oxide (N2O) evolved from soil could improve our understanding of the relative contributions of the main microbial processes (nitrification and denitrification) responsible for N2O formation in soil. However, interpretation of the isotopic data in N2O is complicated by the lack of knowledge of fractionation parameters by different microbial processes responsible for N2O production and consumption. Here we report isotopic enrichment for both nitrogen and oxygen isotopes in two stages of denitrification, N2O production and N2O reduction. We found that during both N2O production and reduction, enrichments were higher for oxygen than nitrogen. For both elements, enrichments were larger for N2O production stage than for N2O reduction. During gross N2O production, the ratio of δ18O‐to‐δ15N differed between soils, ranging from 1.6 to 2.7. By contrast, during N2O reduction, we observed a constant ratio of δ18O‐to‐δ15N with a value near 2.5. If general, this ratio could be used to estimate the proportion of N2O being reduced in the soil before escaping into the atmosphere. Because N2O‐reductase enriches N2O in both isotopes, the global reduction of N2O consumption by soil may contribute to the globally observed isotopic depletion of atmospheric N2O.
An aquaculture‐based method for calibrated bivalve isotope paleothermometry
Authors: Wanamaker Alan D. , Kreutz Karl J. , Borns Harold W. , Introne Douglas S. , Feindel Scott , Barber Bruce J.
Published: September 2006

To quantify species‐specific relationships between bivalve carbonate isotope geochemistry (δ18Oc) and water conditions (temperature and salinity, related to water isotopic composition [δ18Ow]), an aquaculture‐based methodology was developed and applied to Mytilus edulis (blue mussel). The four‐by‐three factorial design consisted of four circulating temperature baths (7, 11, 15, and 19°C) and three salinity ranges (23, 28, and 32 parts per thousand (ppt); monitored for δ18Ow weekly). In mid‐July of 2003, 4800 juvenile mussels were collected in Salt Bay, Damariscotta, Maine, and were placed in each configuration. The size distribution of harvested mussels, based on 105 specimens, ranged from 10.9 mm to 29.5 mm with a mean size of 19.8 mm. The mussels were grown in controlled conditions for up to 8.5 months, and a paleotemperature relationship based on juvenile M. edulis from Maine was developed from animals harvested at months 4, 5, and 8.5. This relationship [T°C = 16.19 (±0.14) − 4.69 (±0.21) {δ18Oc VPBD − δ18Ow VSMOW} + 0.17 (±0.13) {δ18Oc VPBD − δ18Ow VSMOW}2; r2 = 0.99; N = 105; P < 0.0001] is nearly identical to the Kim and O'Neil (1997) abiogenic calcite equation over the entire temperature range (7–19°C), and it closely resembles the commonly used paleotemperature equations of Epstein et al. (1953) and Horibe and Oba (1972). Further, the comparison of the M. edulis paleotemperature equation with the Kim and O'Neil (1997) equilibrium‐based equation indicates that M. edulis specimens used in this study precipitated their shell in isotopic equilibrium with ambient water within the experimental uncertainties of both studies. The aquaculture‐based methodology described here allows similar species‐specific isotope paleothermometer calibrations to be performed with other bivalve species and thus provides improved quantitative paleoenvironmental reconstructions.
A Nd isotopic study of southern sourced waters and Indonesian Throughflow at intermediate depths in the Cenozoic Indian Ocean
Authors: Martin Ellen E. , Scher Howie
Published: September 2006

We present Nd isotopic data for fossil fish teeth recovered from the past 40 m.y. at ODP Site 757, currently located at 1650 m water depth on the Ninetyeast Ridge in the Indian Ocean. Although Site 757 sits in a region strongly influenced by weathering inputs from the Himalayas and volcanic inputs from the Indonesian arc, the pattern of Nd isotopic variations does not appear to respond to these potential sources of Nd. Instead, secular variations correlate to changes in the composition of intermediate to deep water masses bathing the site and circulation patterns in the Indian Ocean. From ∼40 to 10 Ma, ɛNd values and the pattern of change at Site 757 closely match those of ODP Site 1090, a deep water site in the Atlantic sector of the Southern Ocean. Comparison to data from several Fe‐Mn crusts in the Indian Ocean suggests that intermediate to deep water flow paths were similar to the modern distribution of Circumpolar Deep Water. At approximately 10 Ma, Nd isotopic values increase in a step function by 2 ɛNd units, suggesting that plate motions had carried Site 757 into a region influenced by Indonesian Throughflow. Estimates of the vertical and horizontal position of this site at 10 Ma imply that Indonesian Throughflow extended as far south as ∼20°S and to a depth of ∼1500 m. From 10 to 0 Ma, Nd isotopic variations at Site 757 appear to record variations in Indonesian Throughflow. From 10 to 5.5 Ma, values at Site 757 overlap with those from crusts located in the southwest Pacific, indicating extensive flow through the Indonesian Seaway. From 5.5 to 3.4 Ma, ɛNd values become less radiogenic at Site 757 and more radiogenic in the southwest Pacific, suggesting increasing closure of the seaway and concomitant rerouting of equatorial Pacific waters. Beginning at 3.4 Ma, ɛNd values become more radiogenic again at Site 757, which may be attributed to enhanced opening of the seaway or to a change in the source of Throughflow waters from a southern to a northern Pacific region.
Headward growth of chasmata by volatile outbursts, collapse, and drainage: Evidence from Ganges chaos, Mars
Authors: Rodriguez J. A. P. , Kargel Jeffrey , Crown David A. , Bleamaster Leslie F. , Tanaka Kenneth L. , Baker Victor , Miyamoto Hideaki , Dohm James M. , Sasaki Sho , Komatsu Goro
Published: September 2006

The nature and significance of collapse processes in Capri, Eos, and Ganges Chasmata remain poorly understood. Using Ganges Chasma as a type locality, these chasmata are interpreted to be the result of clustering and assimilation of multiple chaotic terrains, which primarily formed by localized depressurization‐induced or thermally‐triggered dissociation of buried gas clathrate hydrates and explosive eruption of gas‐saturated ground water. Such crustal destabilization could have been triggered by (1) deep fracture propagation from the Martian surface, (2) magmatic intrusions and associated heating and inflation‐induced terrain fracturing, and/or (3) climatic thaw and thinning/weakening of the permafrost over the clathrate and gas‐rich groundwater zones. Volume increases associated with release of gases contributed to the expulsion of groundwater and fluidized sediments at the surface, thereby carving the higher outflow channels peripheral to the chasmata and the lower outflow channel floors of the chasmata and outflow channels.
Role of non‐adiabatic processes in the creation of the outer radiation belts
Authors: Fox Nicola J. , Mauk Barry H. , Blake J. Bernard
Published: September 2006

Addressed here are characteristics of processes generating Earth's outer electron radiation region between ∼2 and 7 RE with electron energies from 100's of keV to greater than a few MeV. The question is: To what extent are non‐adiabatic processes required in the creation of the outer radiation belt from the purported source population, the plasmasheet residing beyond 10 RE? Using data sampled within the plasmasheet by the ISEE‐1 satellite, we determine the phase space densities (PSDs) achievable by adiabatic transport processes alone from the plasmasheet and compare them with PSDs at various L‐values within the radiation belt, measured by the CRESS spacecraft. Because processes that might reduce transported PSDs are not included, the comparison yields a lower limit to the effects of non‐adiabatic processes. We find non‐adiabatic processes have a profound affect on outer radiation belt electrons with energies greater than ∼1 MeV, and most clearly between equatorial geocentric distances 5 to 7 RE.
High‐resolution electron temperature measurements using the plasma line asymmetry
Authors: Nicolls M. J. , Sulzer M. P. , Aponte N. , Seal R. , Nikoukar R. , González S. A.
Published: September 2006

In this paper, we present the first results of a new technique for measuring the electron temperature in the daytime ionosphere using the Arecibo incoherent scatter radar (ISR). The technique utilizes the plasma line component of the incoherent scatter spectrum. The difference in the up‐ and down‐shifted plasma line frequencies is related to the density and temperature of the ionosphere, as well as more minor effects resulting from photoelectrons, currents, and other sources. The shift is very small (the order of 1 kHz in a plasma line frequency of several MHz) but can be measured quite accurately with the coded long pulse plasma line technique. We compare the results to ion line measurements of the electron temperature, and the two independent techniques show good agreement. In addition to providing a measure of the electron temperature that is independent of the ion line, the approach allows for a sensitive test of kinetic plasma theory including a magnetic field, gives us the ability to study photoelectron populations and electron currents, and will allow us to constrain ion line fits in the bottomside (and possibly topside) regions to more accurately fit for composition.
A Lagrangian identification of major sources of Sahel moisture
Authors: Nieto Raquel , Gimeno Luis , Trigo Ricardo M.
Published: September 2006

The drying trend in the Sahelian region from the 1950s to the 1990s was a hotspot of decadal‐scale changes in the climate of the 20th century. However, the sources of moisture in this region have been poorly studied. Motivated by the excellent skills of a new Lagrangian method of diagnosis for identifying the sources of moisture over a region (Stohl and James, 2004, 2005), this study examines the main sources over the Sahel. The method computes budgets of evaporation minus precipitation by calculating changes in the specific humidity along the trajectories. We tracked the air masses residing over the Sahel over a period of five years (2000–2004). Recycling was identified as the major source of moisture over the Sahel. Two additional sources of moisture reaching Sahel have been identified here, namely; 1) a band in the North Atlantic stretching between the Sahel and Iberia, and 2) the entire Mediterranean basin, and the nearby Red Sea.
Global distribution of total ozone on Mars from SPICAM/MEX UV measurements
Authors: Perrier S. , Bertaux J. L. , Lefèvre F. , Lebonnois S. , Korablev O. , Fedorova A. , Montmessin F.
Published: September 2006

The dual UV/IR spectrometer SPICAM on board the European mission Mars Express is dedicated to monitoring the Martian atmosphere and has recorded spectra for more than one Martian year, from January 2004 to April 2006, over a large range of latitudes and longitudes. SPICAM UV spectra were recorded on the day side in a nadir geometry, in the 110–320 nm range, allowing measurement of ozone absorption around 250 nm. The method used to retrieve column‐integrated ozone quantities is described. A full radiative transfer forward model of the radiance factor is used in an iterative loop to fit the data with four parameters: the surface albedo at 210 and 300 nm, the dust opacity, and the total ozone column. The analysis of the complete data set is presented. The global climatology of ozone on Mars is retrieved for the first time with spatial and temporal coverage. The most significant findings are (1) large increases in the ozone column density at high latitudes during late winter‐early spring of each hemisphere that totally disappear during summer, (2) a large variability of the northern spring content related to the polar vortex oscillations, (3) low ozone columns in the equatorial regions all year long, and (4) local variations of the ozone column related to topography, mainly above Hellas Planitia. A good overall agreement is obtained comparing SPICAM data to predictions of a Chemical General Circulation Model. However, significant discrepancies in total abundances are found near northern spring when ozone reaches its annual peak. These results will help further understanding of the dynamics and chemistry of Mars atmosphere.
Three view electronically scanned interferometer for plasma electron density measurements on the H-1 heliac
Authors: Oliver David , Howard John , Kumar Santhosh T. A. , Pretty D. G. , Blackwell B. D.
Published: September 2006

We report the development of a three view electronically scanned millimeter-wave interferometer for plasma electron density profile measurement on the H-1 heliac. The system utilizes an electronically tunable backward-wave oscillator whose output is incident on a fixed blazed diffraction grating such that sweeping the source frequency effects a spatial scan of the plasma cross section. Two diagonal views essentially span most of the plasma cross section, while the horizontal arm views the lower half of the plasma. The diffracted beams traverse the plasma in <1ms with a spatial resolution ∼20mm. A study of the density projection dependence on magnetic configuration shows that the presence of low-order rational surfaces in the plasma gives rise to sharp density gradients in the vicinity of the surface.
Diagnosing radiation drive asymmetry and absorbed energy in ignition Hohlraums using gas-filled capsules
Authors: Hoffman Nelson M. , Wilson Douglas C. , Kyrala George A.
Published: September 2006

The shape of the x-ray self-emission image from an imploded inertial confinement fusion capsule has been used to diagnose Hohlraum radiation drive asymmetry [L. J. Suter et al., Phys. Rev. Lett. 73, 2328 (1994); A. Hauer et al., Rev. Sci. Instrum. 66, 672 (1995); A. Hauer et al., Phys. Plasmas 2, 2488 (1995); N. D. Delameter et al., Phys. Plasmas 3, 2022 (1996)]. Timing of neutron yield from the implosion can also be used to diagnose the absorbed radiation drive energy. We propose a set of beryllium capsules filled with gas, rather than layered cryogenic ice, to diagnose asymmetry and absorbed energy in ignition Hohlraums. Capsules with a range of initial shell thickness have a corresponding range of implosion times, allowing sampling of drive conditions throughout an ignition pulse. For example a 12μm thick shell implodes during the foot of the ignition pulse, sampling the drive up to about 10ns. For such capsules, the foot pulse is a high-adiabat drive and leads to implosions that are rather robust against instability and mixing. In these capsules, the best time to record images for diagnosing asymmetry may be several hundred picoseconds after peak x-ray brightness, when the image distortion is increasing rapidly.
High-repetition CO2 laser for collective Thomson scattering diagnostic of α particles in burning plasmas
Authors: Kondoh T. , Hayashi T. , Kawano Y. , Kusama Y. , Sugie T. , Miura Y. , Koseki R. , Kawahara Y.
Published: September 2006

A high-repetition and high-energy transversely excited atmospheric carbon dioxide (CO2) laser for a collective Thomson scattering (CTS) diagnostic has been developed to establish a diagnostic method of confined α particles in burning plasmas. To excite a single-transverse and single-longitudinal mode, a continuous wave seed laser was injected to an unstable resonator with a cavity length of ∼4.4m. Pulse energy of 10J with a repetition rate of 10Hz has been achieved in the single-mode operation. Pulse energies of 18J with a repetition rate of 10Hz and 36J with single shot operation have also been achieved in the multimode operation. These results give a prospect for the CTS diagnostic on International Thermonuclear Experimental Reactor (ITER), which requires single-mode energy of 20J with repetition rate of 40Hz.
High-speed three-wave polarimeter-interferometer diagnostic for Madison symmetric torus
Authors: Deng B. H. , Brower D. L. , Ding W. X. , Wyman M. D. , Chapman B. E. , Sarff J. S.
Published: September 2006

A high-speed three-wave polarimeter-interferometer diagnostic has been developed on the Madison symmetric torus reversed field pinch to provide simultaneous measurement of electron density and poloidal magnetic field profile evolution. With increased digitizer bandwidth, polarimetry noise due to aliasing and cross-talk is minimized, and time response improved. System performance is demonstrated by measurements of equilibrium profile evolution during fast events such as the sawtooth crash and pellet injection.
Gated x-ray detector for the National Ignition Facility
Authors: Oertel John A. , Aragonez Robert , Archuleta Tom , Barnes Cris , Casper Larry , Fatherley Valerie , Heinrichs Todd , King Robert , Landers Doug , Lopez Frank , Sanchez Phillip , Sandoval George , Schrank Lou , Walsh Peter , Bell Perry , Brown Matt , Costa Robert , Holder Joe , Montelongo Sam , Pederson Neal
Published: September 2006

Two new gated x-ray imaging cameras have recently been designed, constructed, and delivered to the National Ignition Facility in Livermore, CA. These gated x-Ray detectors are each designed to fit within an aluminum airbox with a large capacity cooling plane and are fitted with an array of environmental housekeeping sensors. These instruments are significantly different from earlier generations of gated x-ray images due, in part, to an innovative impedance matching scheme, advanced phosphor screens, pulsed phosphor circuits, precision assembly fixturing, unique system monitoring, and complete remote computer control. Preliminary characterization has shown repeatable uniformity between imaging strips, improved spatial resolution, and no detectable impedance reflections.
Three-dimensional modeling and inversion of x-ray pinhole detector arrays
Authors: Tritz K. , Stutman D. , Delgado-Aparicio L. , Finkenthal M.
Published: September 2006

X-ray pinhole detectors are a common and useful diagnostic for high temperature and fusion-grade plasmas. While the measurements from such diagnostics are line integrated, local emission can be recovered by inverting or modeling the data using varying assumptions including toroidal symmetry, flux surface isoemissivity, and one-dimensional (1D) chordal lines of sight. This last assumption is often valid when the structure sizes and gradient scale lengths of interest are much larger than the spatial resolution of the detector elements. However, x-ray measurements of, for example, the strong gradients in the H-mode pedestal may require a full three-dimensional (3D) treatment of the detector geometry when the emission of the plasma has a significant variation within the field of view, especially in a high-triangularity, low aspect ratio plasma. Modeling of a high spatial resolution tangential edge array for NSTX has shown that a proper 3D treatment can improve the effective spatial resolution of the detector by 10%–40% depending on the modeled signal-to-noise ratio and gradient scale length. Results from a general treatment of arbitrary detector geometry will provide a guideline for the amount of systematic error that can be expected by a 1D versus 3D field of view analysis.
Application of precise phase detector for density profile and fluctuation measurements using CO2 imaging heterodyne interferometer on LHD
Authors: Vyacheslavov L. N. , Khilchenko A. D. , Zubarev P. V. , Tanaka K. , Michael C. , Sanin A. L. , Kawahata K. , Okajima S.
Published: September 2006

The two-color CO2∕YAG laser imaging heterodyne interferometer was recently equipped with a precise digital phase counter (eight channels, 0.5mrad resolution, 1MHz carrier frequency and sampling rate, 500kHz bandwidth, ±250rad recording range, and a maximum data record of 8.4×106 samples/channel). This modification enables detailed measurements of plasma density dynamics during pellet ablation and, in addition, observations of density fluctuations. Examples of fast rising density peaks in pellet discharges as well as spatial and spectral characteristics of plasma density fluctuations obtained with the heterodyne interferometer are presented.
Motional Stark effect diagnostic expansion on DIII-D for enhanced current and Er profile measurements
Authors: Holcomb C. T. , Makowski M. A. , Jayakumar R. J. , Allen S. A. , Ellis R. M. , Geer R. , Behne D. , Morris K. L. , Seppala L. G. , Moller J. M.
Published: September 2006

The motional Stark effect (MSE) diagnostic on DIII-D has been expanded to take advantage of a change in the neutral beam geometry, adding 24 new MSE channels viewing a beam injected counter to the plasma current. When data from these channels are used with those from two older MSE arrays viewing a different beam, the overall radial resolution improves near the magnetic axis at least a factor of 2, and the uncertainty in calculations of vertical magnetic field and radial electric field decreases in the edge at least a factor of 4. The new design uses two optical systems mounted on the same vacuum port with a common shutter and shielding.
Domain wall and periodic solutions of coupled ϕ4 models in an external field
Authors: Khare Avinash , Saxena Avadh
Published: September 2006

Coupled double well (ϕ4) one-dimensional potentials abound in both condensed matter physics and field theory. Here we provide an exhaustive set of exact periodic solutions of a coupled ϕ4 model in an external field in terms of elliptic functions (domain wall arrays) and obtain single domain wall solutions in specific limits. We also calculate the energy and interaction between solitons for various solutions. Both topological and nontopological (e.g., some pulse-like solutions in the presence of a conjugate field) domain walls are obtained. We relate some of these solutions to the recently observed magnetic domain walls in certain multiferroic materials and also in the field theory context wherever possible. Discrete analogs of these coupled models, relevant for structural transitions on a lattice, are also considered.
Surface enhanced Raman optical activity of molecules on orientationally averaged substrates: Theory of electromagnetic effects
Authors: Janesko Benjamin G. , Scuseria Gustavo E.
Published: September 2006

We present a model for electromagnetic enhancements in surface enhanced Raman optical activity (SEROA) spectroscopy. The model extends previous treatments of SEROA to substrates, such as metal nanoparticles in solution, that are orientationally averaged with respect to the laboratory frame. Our theoretical treatment combines analytical expressions for unenhanced Raman optical activity with molecular polarizability tensors that are dressed by the substrate’s electromagnetic enhancements. We evaluate enhancements from model substrates to determine preliminary scaling laws and selection rules for SEROA. We find that dipolar substrates enhance Raman optical activity (ROA) scattering less than Raman scattering. Evanescent gradient contributions to orientationally averaged ROA scale to first or higher orders in the gradient of the incident plane-wave field. These evanescent gradient contributions may be large for substrates with quadrupolar responses to the plane-wave field gradient. Some substrates may also show a ROA contribution that depends only on the molecular electric dipole–electric dipole polarizability. These conclusions are illus trated via numerical calculations of surface enhanced Raman and ROA spectra from (R)-(−)-bromochlorofluoromethane on various model substrates.
A class of superintegrable systems of Calogero type
Authors: Smirnov Roman G. , Winternitz Pavel
Published: September 2006

We show that the three-body Calogero model with inverse square potentials can be interpreted as a maximally superintegrable and multiseparable system in Euclidean three-space. As such it is a special case of a family of systems involving one arbitrary function of one variable.
Measuring the wicking behavior of textiles by the combination of a horizontal wicking experiment and image processing
Authors: Morent Rino , De Geyter Nathalie , Leys Christophe , Vansteenkiste Ewout , De Bock Johan , Philips Wilfried
Published: September 2006

A horizontal wicking experiment is proposed to measure the wicking behavior of textiles. A syringe supplying a continuous flow of distilled water is in contact with the absorbing fabric resulting in a wicking region. The increase in wicking area or the wicking area after a certain time is recorded with a digital camera. The picture analyzing process is automated by the use of two complementary image segmentation algorithms: morphological segmentation and region merging. Where commercial image analyzing software fails due to the specific porous structure of textiles, the developed algorithms succeed in calculating the wicking area semiautomatically. It is shown that the newly developed technique is able to test the wicking behavior of, e.g., a cotton fabric and a plasma treated polyester nonwoven.
Method of characterizing electrical contact properties of carbon nanotube coated surfaces
Authors: Yaglioglu Onnik , John Hart A. , Martens Rod , Slocum Alexander H.
Published: September 2006

We present a method for electromechanical characterization of carbon nanotube (CNT) films grown on silicon substrates as potential electrical contacts. The method includes measuring the sheet resistance of a tangled CNT film, measuring the contact resistance between two tangled CNT films, and investigating the dependence on applied force and postgrowth annealing. We also characterize Au-CNT film contact resistance by simultaneous measurement of applied force and resistance. We measure a contact resistance as low as 0.024Ω∕mm2 between two films of tangled single-wall carbon nanotubes grown on a polished silicon substrate and observe an electromechanical behavior very similar to that predicted by classical contact theory.
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, ultrahigh vacuum scanning tunneling microscope having two orthogonal tips with tunnel junctions as close as a few nanometers
Authors: Xu J. F. , Thibado P. M. , Ding Z.
Published: September 2006

An instrument that incorporates two scanning tunneling microscope (STM) tips which can have their tunnel junctions as close together as a few nanometers was designed and built. The sample is fixed and can be imaged simultaneously and independently with both STM tips. The tips and sample can be positioned and angled to image the same surface or perpendicular surfaces. The entire STM head is cooled with liquid helium to about 4K while in an ultrahigh vacuum environment. Macroscopic positioning of the tips is accomplished using piezoelectric “stick-slip” coarse motion stages, whereas atomic positioning is accomplished with piezoelectric tube scanners. This instrument addresses the critical need to locally characterize individual nanostructures and heterostructures.