bluuebunny/crossref_metadata_2025 huggingface dataset:
Saccharide Sensing Based on Saccharide‐Induced Conformational Changes in Fluorescent Boronic Acid Polymers
Authors: Kanekiyo Yasumasa , Sato Hiroaki , Tao Hiroaki
Published: September 2005

Summary: A novel fluorometric saccharide detection strategy has been established by utilizing saccharide‐induced conformational changes in copolymers containing boronic acid and fluorescent units. The polymer chain changes its conformation due to an alteration of the charge state induced by binding with saccharides. The conformational changes are conveniently detected by monitoring excimer to monomer intensity ratio in the fluorescence spectra. Thus, the present strategy would be a promising way for the creation of highly selective and sensitive saccharide‐sensing systems.

Saccharide‐induced conformational change in copolymers containing boronic acid units.

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Saccharide‐induced conformational change in copolymers containing boronic acid units.
Microfocus X‐Ray Scattering Scanning Microscopy for Polymer Applications
Authors: Zafeiropoulos Nikolaos E. , Davies Richard J. , Roth Stephan V. , Burghammer Manfred , Schneider Konrad , Riekel Christian , Stamm Manfred
Published: September 2005

Summary: The fracture properties of polymers are one of the key parameters that define their service life and limit their applications. One of the most interesting and important questions is how the molecular architecture and the structure of polymers at nanolength scales influence their fracture properties. X‐ray scattering is a powerful means of probing bulk structures at the nanometre scale. It can therefore provide a wealth of information relating to such structure‐property relationships. In the present study, synchrotron radiation microfocus small‐angle X‐ray scattering is used to investigate the damage area ahead and around the crack tip in polyamide 6 (PA6). The results reveal that the damage area propagates far beyond the visible crack, and inside the damaged zone platelet‐shaped cracks/voids are formed.

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Cover Picture: Macromol. Rapid Commun. 18/2005
Authors: Lu Hongbin , Shen Hongbin , Song Zhenlun , Shing Katherine S. , Tao Wei , Nutt Steven
Published: September 2005

Cover: Natural silicate nanorods, attapulgite, show significant improvements in mechanical properties and dimensional stability of epoxy resin, which are easy to uniformly disperse in the organic media after modification and exhibit good commercial potential. Further details can be found in the Communication by H. Lu, H. Shen, Z. Song, K. S. Shing, W. Tao, and S. Nutt* on page 1445.
A hybrid qualitative method for pretesting questionnaires: The example of a questionnaire to caregivers of Alzheimer disease patients
Authors: Oremus Mark , Cosby Jarold L. , Wolfson Christina
Published: September 2005

A hybrid method based on cognitive interviewing and consensus panels was developed to pretest a questionnaire for caregivers of persons with Alzheimer disease (AD). The objective of the questionnaire was to elicit caregivers' attitudes and opinions on the use of medications to treat the disease. Thirty‐one caregivers were divided into five pretest groups, within which each participant was asked to comment on questionnaire wording and design. The comments from participants in the first three groups were used to revise the questionnaire, and the revised version was given to participants in the remaining two groups. Overall, 81% (118/146) of the participants' comments were implemented. The number of comments made in the last two groups decreased relative to the number of comments made in the first three groups. The hybrid method enhanced the user‐friendliness of the questionnaire and can serve as an alternative to common ad hoc pretest approaches that have little basis in theory. © 2005 Wiley Periodicals, Inc. Res Nurs Health 28: 419–430, 2005.
Resident–caregiver relationships and thriving among nursing home residents
Authors: Bergland Ådel , Kirkevold Marit
Published: September 2005

The purpose of this study was to describe nursing home residents' experiences and perceptions of relationships with caregivers and to explore their importance to thriving. Data were collected through field observations and open‐ended interviews with 26 residents. Receiving appropriate care from kind caregivers made life easier for all residents but contributed to thriving only for some. One group of residents emphasized personal relationships to individual caregivers as essential to thriving. A second group reported that non‐personal relationships contributed to thriving. A third group preferred distant relationships to the caregivers but reported thriving as well. Personal relationships to individual caregivers were not essential to thriving for all residents. © 2005 Wiley Periodicals, Inc. Res Nurs Health 28: 365–375, 2005.
Decisional balance for exercise: Adaptation of an instrument for older Mexican American women
Authors: Laffrey Shirley Cloutier , Lee Young Shin
Published: September 2005

The purpose of this study was to adapt and test an instrument to measure decisional balance for exercise with older Mexican American women. Items were derived from a Decisional Balance Scale (DBS) developed by Marcus, Rakowski, and Rossi (1992) and a focus group with Mexican American women aged 60 to 86 years. The adapted Spanish‐English DBS was administered to 75 Mexican American women (38 exercisers and 37 non‐exercisers). A factor analysis yielded a positive and a negative factor. Alpha coefficients were .95 for the positive factor and .79 for the negative factor. Decisional balance for exercise was significantly more positive for the exercisers than for the non‐exercisers and was positively related to exercise readiness and habitual activity. The findings suggest that the adapted Spanish‐English DBS can be used in exercise and activity research with older Mexican American women. © 2005 Wiley Periodicals, Inc. Res Nurs Health 28: 388–397, 2005.
Synthesis and characterization of amphiphilic triblock copolymers by iron‐mediated atom transfer radical polymerization
Authors: Ibrahim Khalid , Starck Paul , Löfgren Barbro , Seppälä Jukka
Published: September 2005

The atom transfer radical polymerization of methyl methacrylate (MMA) and n‐butyl methacrylate (n‐BMA) was initiated by a poly(ethylene oxide) chloro telechelic macroinitiator synthesized by esterification of poly(ethylene oxide) (PEO) with 2‐chloro propionyl chloride. The polymerization, carried out in bulk at 90 °C and catalyzed by iron(II) chloride tetrahydrate in the presence of triphenylphosphine ligand (FeCl2 · 4H2O/PPh3), led to A–B–A amphiphilic triblock copolymers with MMA or n‐BMA as the A block and PEO as the B block. A kinetic study showed that the polymerization was first‐order with respect to the monomer concentration. Moreover, the experimental molecular weights of the block copolymers increased linearly with the monomer conversion, and the molecular weight distribution was acceptably narrow at the end of the reaction. These block copolymers turned out to be water‐soluble through the adjustment of the content of PEO blocks (PEO content >90% by mass). When the PEO content was small [monomer/macroinitiator molar ratio (M/I) = 300], the block copolymers were water‐insoluble and showed only one glass‐transition temperature. With an increase in the concentration of PEO (M/I = 100 or 50) in the copolymer, two glass transitions were detected, indicating phase separation. The macroinitiator and the corresponding triblock copolymers were characterized with Fourier transform infrared, proton nuclear magnetic resonance, size exclusion chromatography analysis, dynamic mechanical analysis, and differential scanning calorimetry. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5049–5061, 2005
The synthesis of novel aliphatic bis(acenaphthelene) reactive monomers
Authors: Wooster Tim J. , Abrol Simmi , Hey Jeffrey M. , MacFarlane Douglas R.
Published: September 2005

Novel aliphatic‐bridged bis(acenaphthalene)s are synthesized and evaluated as potential precursors to high‐temperature reactive monomers. It was found that as the length of the aliphatic bridging unit increased, the thermal stability of bis(acenaphthalene) increased and melting point decreased. The use of an alternative route for the introduction of the reactive vinyl group resulted in a dramatic increase in monomer purity. The increase in monomer purity resulted in the creation of a processing window that enabled samples to be melt cast prior to polymerization, greatly improving their suitability as high‐temperature polymers. Polymerized samples were found to have high thermal stability, indicating they have potential as high temperature materials. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43:5072–5082, 2005
Preparation and characterization of redox cellulose Langmuir–Blodgett films containing a ferrocene derivative
Authors: Ifuku Shinsuke , Tsujii Yoshinobu , Kamitakahara Hiroshi , Takano Toshiyuki , Nakatsubo Fumiaki
Published: September 2005

The 3‐ferrocenoylpropanoyl group, one of the redox species, was introduced at C‐2 and/or C‐3 positions of 6‐O‐(4‐stearyloxytrityl)cellulose. The spreading behavior of the cellulose derivatives on the water surface and the properties of Langmuir–Blodgett (LB) films were investigated. The surface pressure–area isotherm of the cellulose monolayer was changed by the subphase temperature. Uniform monolayers of 6‐O‐(4‐stearyloxytrityl)cellulose 3‐ferrocene propionate (STCFc) could be deposited successively onto several substrates by the horizontal lifting method at 10 mN m−1, and this produced X‐type LB films. The successive uniform depositions of STCFc were confirmed by ultraviolet–visible absorption spectra. X‐ray diffraction measurements indicated that the thickness of the STCFc molecules in the LB films was 1.99 nm. Fourier transform infrared spectroscopy measurements supported the idea that hydrocarbon chains in the LB films were highly ordered (trans‐zigzag) and oriented considerably perpendicular to the surface of the substrate. Moreover, the CO group of the ferrocenoyl groups was perpendicular to the surface of the substrate, and the ferrocene group was occupied in the water phase. Cyclic voltammograms for the STCFc monolayer on a gold electrode exhibited surface waves. The interfacial electron‐transfer process between the redox site incorporated into the cellulose LB monolayer and the electrode surface was fast enough at a scanning rate lower than 100 mV s−1. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5023–5031, 2005
Preparation and polymerization of a water‐soluble, nonbonding crosslinking agent for a mechanically crosslinked hydrogel
Authors: Kubo Masataka , Matsuura Toyohiro , Morimoto Hiromi , Uno Takahiro , Itoh Takahito
Published: September 2005

A novel water‐soluble cyclic macromonomer based on a cyclic potassium polyacrylate was prepared. The radical polymerization of acrylamide in the presence of the cyclic macromonomer was carried out to obtain a mechanically crosslinked polyacrylamide. The terpolymerization of acrylamide, sodium acrylate, and the cyclic macromonomer gave a mechanically crosslinked polyelectrolyte with high swellability. The mechanically crosslinked polyelectrolyte exhibited large volume shrinkage in a water solution of Cu(II) salt. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5032–5040, 2005
High electroluminescent properties of conjugated copolymers from poly[9,9‐dioctylfluorenyl‐2,7‐vinylene]‐co‐(2‐(3‐dimethyldodecylsilylphenyl)‐1,4‐phenylene vinylene)] for light‐emitting diode applications
Authors: Jin Sung‐Ho , Jung Hwan‐Hee , Hwang Chan‐Koo , Koo Dae‐Sung , Shin Won Suk , Kim Yeong‐Inn , Wook Lee Jae , Gal Yeong‐Soon
Published: September 2005

A new series of copolymers with high brightness and luminance efficiency were synthesized using the Gilch polymerization method, and their electro‐optical properties were investigated. The weight‐average molecular weights (Mw) and polydispersities of the synthesized poly(9,9‐dioctylfluorenyl‐2,7‐vinylene) [poly(FV)], poly[2‐(3‐dimethyldodecylsilylphenyl)‐1,4‐phenylenevinylene] [poly(m‐SiPhPV)], and poly[9,9‐di‐n‐octylfluorenyl‐2,7‐vinylene]‐co‐(2‐(3‐dimethyldodecylsilylphenyl)‐1,4‐phenylene vinylene)] [poly(FV‐co‐m‐SiPhPV)] were found to be in the ranges of (8.7–32.6) × 104 and 2.3–5.4, respectively. It was found that the electro‐optical properties of the copolymers could be adjusted by controlling the feed ratios of the comonomers. Thin films of poly(FV), poly(m‐SiPhPV), and poly(FV‐co‐m‐SiPhPV) were found to exhibit photoluminescence quantum yields between 21% and 42%, which are higher than those of MEH‐PPV. Light‐emitting diodes were fabricated in ITO/PEDOT/light‐emitting polymer/cathode configurations using either double layer (LiF/Al) or triple layer (Alq3/LiF/Al) cathode structures. The performance of the polymer light‐emitting diodes (PLEDs) with triple layer cathodes was found to be better than that of the PLEDs with double layer cathodes in poly(FV) and poly(FV‐co‐m‐SiPhPV). The turn‐on voltages of the PLEDs were in the range of 4.5–6.0 V, with maximum brightness and luminance efficiency up to 9691 cd/m2 at 16 V and 3.27 cd/A at 13 V, respectively. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5062–5071, 2005
The antisite LuAl defect‐related trap in Lu3Al5O12:Ce single crystal
Authors: Nikl M. , Mihokova E. , Pejchal J. , Vedda A. , Zorenko Yu. , Nejezchleb K.
Published: September 2005

Absorption, radioluminescence and thermoluminescence spectra were measured for a set of Lu3Al5O12:Ce samples consisting of a bulk single crystal and Liquid Phase Epitaxy‐grown films prepared from the same raw materials. The triple peak structure within 120–200 K distinguished in thermolu‐ minescence glow curves of the bulk crystals was ascribed to an electron trap arising due to the LuAl antisite defect. The depth of the trap associated with the dominant peak at 142 K was evaluated using the initial rise method. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Defect structure of ZrO2‐doped rare earth perovskite scintillators
Authors: Stanek C. R. , Levy M. R. , McClellan K. J. , Uberuaga B. P. , Grimes R. W.
Published: September 2005

The efficiency of scintillator materials is decreased by processes associated with electrons or holes trapped at point defects. It therefore follows that minimizing the concentration of the defects responsible for trapped electrons/holes will in‐ crease the scintillator efficiency. It has been proposed that annealing or doping oxide scintillators with aliovalent ions can change the concentration of point defects (M. Nikl, phys. stat. sol. (a) 178, 595 (2000) [1]). Here, we predict the defect structures corresponding to ZrO2 doping in a series of rare earth aluminate (REAlO3) perovskites. From these calculations, we predict the mechanism leading to the decrease in oxygen vacancy concentration (the predominant electron trap in REAlO3). We propose this mechanism to be an example of “defect engineering”, where a particularly egregious defect is traded for a less deleterious defect. These results can be used to further optimize such scintillator materials.

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A perfect REAlO3 orthorhombic perovskite unit cell (a), compared to the same unit cell with the defects associated with ZrO2 doping, namely $ {\rm Zr}^\bullet _{\rm RE} $, $ {\rm Zr}^\bullet _{\rm Al} $ and $ {\rm O}'' _{\rm i} $ (b).

(© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Repeatability of the sonographic assessment of fetal sucking and swallowing movements
Authors: Levy D. S. , Zielinsky P. , Aramayo A. M. , Behle I. , Stein N. , Dewes L.
Published: September 2005

Objective

To test the repeatability of sonography in the assessment of fetal sucking and swallowing movements.

Methods

Eighty normal fetuses of pregnant women with no systemic abnormalities were examined sonographically at 30–38 weeks of gestation. Sucking and swallowing movements were observed for 15 min and the face was visualized in frontal and lateral views. The examinations were recorded for later analysis by two independent observers and the 95% limits of agreement (Bland and Altman) method was used for inter‐ and intraobserver comparison.

Results

The mean ± SD number of swallowing movements, sucking bursts and total sucking movements recorded by Observer 1 were 8.3 ± 4.7, 9.9 ± 9.3 and 35.8 ± 48.0 and the equivalent values for Observer 2 were 8.2 ± 4.8, 9.8 ± 9.3 and 36.4 ± 49.0, respectively. The mean (95% limits of agreement) interobserver difference was 0.1 (−1.4; 1.6), 0.1 (−2.2; 2.3) and −0.6 (−9.0; 7.9), and the mean (95% limits of agreement) intraobserver difference was 0.4 (−3.1; 3.9), 0.1 (−2.0; 2.2) and 1.0 (−10.7; 12.7) for swallowing movements, sucking bursts and total sucking movements, respectively.

Conclusions

The high degree of intra‐ and interobserver repeatability disclosed in the sonographic analysis of fetal sucking and swallowing movements supports the applicability of sonographic assessment in normal fetuses. Copyright © 2005 ISUOG. Published by John Wiley & Sons, Ltd.
Population dynamics of Rattus argentiventer, Rattus losea, and Rattus rattus inhabiting a mixed‐farming system in the Red River Delta, Vietnam
Authors: Brown Peter R. , Tuan Nguyen Phu , Singleton Grant R. , Hue Dao Thi , Hoa Phung Thi , Ha Phi Thi Thu , Tan Tran Quang , Van Tuat Nguyen
Published: September 2005

Rodent pests cause significant damage to lowland irrigated rice crops in the Red River Delta of northern Vietnam. Data from a 4‐year study were examined to look at the population dynamics of the ricefield rat, Rattus argentiventer (representing 50% of captures), the lesser ricefield rat, Rattus losea (30% of captures), and the black rat, Rattusrattus complex (9% of captures) that inhabit the irrigated mixed‐cropping system. We tested the hypothesis that these rodent species were breeding in response to the availability of high‐quality food provided by crops rather than in response to rainfall. The abundance of rodents fluctuated annually, with a main peak following the spring rice crop, and a secondary peak following the summer rice crop. There was a strong relationship between the monthly abundance of rats and rainfall, but a weak relationship between monthly rates of increase and rainfall. There were distinct peaks in breeding activity during the reproductive stages of the rice crops suggesting that changes in crop stages were more important than rainfall in this seasonal, but irrigated agroecosystem. The modal litter size for R. argentiventer was 8 (mean of 8.67±0.20 SE, range 2–16), where the mode for R. losea, was 7 (mean of 7.32±0.15 SE, range 3–14). Management of these species needs to be conducted prior to the onset of the main breeding seasons.
the value of patient hydration prior to bone scintigraphy
Authors: stace s. m. , huggett s. m. , denton b. k. , harries a. m.
Published: September 2005

the aim of this study was to establish whether hydration prior to radiopharmaceutical injection, in addition to post injection hydration, contributed any value to image quality during bone scintigraphy. two hundred patients referred for bone imaging over a four month period were randomised into two groups. group a was issued with instructions to hydrate pre and post injection, and group b was only advised to hydrate between injection and scan. equal regions of interest (roi) were then drawn on each image: firstly over the femoral diaphysis, and secondly over the contra-lateral adductor area. the total number of gamma counts from the bone roi and the soft tissue roi was then expressed as a ratio, and a mean value for each group was established.

the mean ratio for group a was found to be 2.25, and for group b 2.30. a t test of variance confirmed that there was no statistical difference between the ratios of the groups (t = 50.272, n = 5100, p = 50.618). it was concluded that hydration levels prior to bone scintigraphy injection, where it is preserved post injection, have no significant effect on the bone-soft tissue (b:st) ratio in the image.
patients with multiple sclerosis: their experiences and perceptions of the mri investigation
Authors: laidlaw a. , henwood s.
Published: September 2005

this qualitative study investigated multiple sclerosis (ms) patients' holistic experience of magnetic resonance imaging (mri). with support from the ms society, eight individuals with ms were interviewed using unstructured, tape-recorded interviews.

the holistic experience was overall a negative one. the most negative aspects being cited as the lack of support and information around the time of diagnosis. the loss of control felt by individuals was also an import ant issue, which led patients to pursue self-empowerment by actively seeking out information and support.

the study suggests improvement in information to patients attending for mri is essential, along with adequate support (including details about the ms society) being offered at the time of receiving confirmed diagnosis and results. the study shows that for some patients, there is a long lasting negative effect from the scan, which impacts on other activities, as well as affecting the patients' willingness to undergo future imaging.
clinical governance: two years experience of reporting discrepancy review in radiology
Authors: vohrah a. , chandy j.
Published: September 2005

this article describes a system for reviewing reporting discrepancies encountered in our department. this system has been in operation for two years and its aim was to learn from errors being encountered. it was introduced as part of our department's approach to clinical governance.
optimising patient care: meeting the needs of the paediatric oncology patient
Authors: o'connor g. , drennan c.
Published: September 2005

the challenge of making life better for the paediatric oncology patient by correctly identifying the specific psychosocial needs of the individual patient is dealt with in this paper. among the topics discussed are the inclusion of the patient's parents in this process, the role of therapeutic play, and the use of a pain scale as a successful intervention. stein's understanding of empathy is dealt with in some detail.
out-patients' expectations of bone scans: do they influence satisfaction?
Authors: rogers h.
Published: September 2005

within the health care sector there is a renewed emphasis on the satisfaction of patients and their involvement in its' evaluation. there is also some evidence to suggest that the expectations of patients play a fundamental part in forming this satisfaction. this study aimed to establish the expectations of bone scan patients who attended a nuclear medicine department and consequently measured their satisfaction after the visit. a possible link between the two was assessed. a questionnaire survey was undertaken to assess the patients' expectations prior to their visit and subsequently their satisfaction after their scan. the questionnaires included comment sections to encourage the addition of free text to the questionnaires by the patients. a total of 181 patients were included in the analysis which provided a range of expectations, with most patients expressing high importance to those expectations. generally satisfaction was found to be high. statistical analysis of the results showed a significant positive correlation between the expectations of patients and their satisfaction. the expectations of patients may therefore be targeted by health professionals in their attempts to provide the care patients need and deserve.
the sonographic appearances of tuberculous epididymo-orchitis
Authors: cantin p.g. , freeman s.j.
Published: September 2005

tuberculous epididymo-orchitis is a condition rarely encountered in countries where tuberculosis is uncommon. patients with scrotal symptoms are likely to be referred for ultrasound examination where an erroneous diagnosis of testicular tumour or non-specific epididymitis may be suggested unless the ultrasound practitioner is aware of the sonographic features of this condition. we report the ultrasound features in a patient with tuberculous epididymo-orchitis.
Tenuous ring formation by the capture of interplanetary dust at Saturn
Authors: Mitchell C. J. , Colwell J. E. , Horányi M.
Published: September 2005

We examine the capture of interplanetary dust particles by Saturn using both a simple two‐dimensional code as well as a three‐dimensional code with more detailed charging currents and forces. The incoming grain's energy may be lost to the magnetosphere due to the grain's finite charging time as it passes through the magnetospheric plasma. The two‐dimensional code uses an equilibrium grain potential as a function of radial position and a charging time as a function of particle size. The ratio of prograde to retrograde captures depends on the shape of the equilibrium potential as a function of distance from the planet, with more prograde captures observed for more negative potentials. In the three‐dimensional simulations, we observe a thick ring of dust particles captured into retrograde orbits. This dust, which has a typical size of 0.1 μm, forms a tenuous ring around the planet extending from the edge of the main rings to ≈9 planetary radii with a thickness of ≈3 planetary radii. We predict that the peak density for retrograde particles is 3 × 10−15 cm−3, which should be observed by the Cassini spacecraft. We expect that with the appropriate viewing geometry, about 20 grains will be detected by the Cosmic Dust Analyzer during the first 4 years of the mission.
Emissions from international shipping: 2. Impact of future technologies on scenarios until 2050
Authors: Eyring V. , Köhler H. W. , Lauer A. , Lemper B.
Published: September 2005

In this study the today's fleet‐average emission factors of the most important ship exhausts are used to calculate emission scenarios for the future. To develop plausible future technology scenarios, first upcoming regulations and compliance with future regulations through technological improvements are discussed. We present geographically resolved emission inventory scenarios until 2050, based on a mid‐term prognosis for 2020 and a long‐term prognosis for 2050. The scenarios are based on some very strict assumptions on future ship traffic demands and technological improvements. The four future ship traffic demand scenarios are mainly determined by the economic growth, which follows the IPCC SRES storylines. The resulting fuel consumption is projected through extrapolations of historical trends in economic growth, total seaborne trade and number of ships, as well as the average installed power per ship. For the future technology scenarios we assume a diesel‐only fleet in 2020 resulting in fuel consumption between 382 and 409 million metric tons (Mt). For 2050 one technology scenario assumes that 25% of the fuel consumed by a diesel‐only fleet can be saved by applying future alternative propulsion plants, resulting in a fuel consumption that varies between 402 and 543 Mt. The other scenario is a business‐as‐usual scenario for a diesel‐only fleet even in 2050 and gives an estimate between 536 and 725 Mt. Dependent on how rapid technology improvements for diesel engines are introduced, possible technology reduction factors are applied to the today's fleet‐average emission factors of all important species to estimate future ship emissions. Combining the four traffic demand scenarios with the four technology scenarios, our results suggest emissions between 8.8 and 25.0 Tg (NO2) in 2020, and between 3.1 to 38.8 Tg (NO2) in 2050. The development of forecast scenarios for CO2, NOx, SOx, CO, hydrocarbons, and particulate matter is driven by the requirements for global model studies of the effects of these emissions on the chemical composition of the atmosphere and on climate. The developed scenarios are suitable for use as input for chemical transport models (CTMs) and coupled chemistry‐climate models (CCMs).
Constraining the first aerosol indirect radiative forcing in the LMDZ GCM using POLDER and MODIS satellite data
Authors: Quaas Johannes , Boucher Olivier
Published: September 2005

The indirect effects of anthropogenic aerosols are expected to cause a significant radiative forcing of the Earth's climate whose magnitude, however, is still uncertain. Most climate models use parameterizations for the aerosol indirect effects based on so‐called “empirical relationships” which link the cloud droplet number concentration to the aerosol concentration. New satellite datasets such as those from the POLDER and MODIS instruments are well suited to evaluate and improve such parameterizations at a global scale. We derive statistical relationships of cloud‐top droplet radius and aerosol index (or aerosol optical depth) from satellite retrievals and fit an empirical parameterization in a general circulation model to match the relationships. When applying the fitted parameterizations in the model, the simulated radiative forcing by the first aerosol indirect effect is reduced by 50% as compared to our baseline simulation (down to −0.3 and −0.4 Wm−2 when using MODIS and POLDER satellite data, respectively).
Representation of a nonspherical ice particle by a collection of independent spheres for scattering and absorption of radiation: 3. Hollow columns and plates
Authors: Grenfell Thomas C. , Neshyba Steven P. , Warren Stephen G.
Published: September 2005

The ability of an assembly of spheres to represent scattering and absorption by a nonspherical ice crystal of the same volume‐to‐area (V/A) ratio was previously evaluated for convex shapes (circular cylinders and hexagonal prisms). Here we extend the comparison to indented and hollow prisms, which are common in ice clouds. In the equivalent‐sphere representation, the crystal mass and surface area are both conserved. Internal surfaces as well as external surfaces contribute to the total surface area; in the model representation both become external surfaces of spheres. The optical depth τ of the model cloud is thus greater than that of the real cloud by the ratio A/4P, where A is the total area of the nonspherical particle and P is the orientation‐averaged projected area. This ratio, which we call “fluffiness,” is unity for convex shapes but may exceed 2 for clusters of hollow bullets. In effect, the scattering at interior surfaces of a hollow crystal becomes classified as multiple scattering in the model of ice spheres. Therefore, rather than directly comparing the asymmetry factor (g) and single‐scattering albedo (ωo) of the hollow crystal to those of the equal‐V/A sphere, it is more appropriate to compare the product τ(1 − g)ωo, because this quantity largely determines the bulk radiative properties of the cloud. Errors in albedo, absorptance, and transmittance of ice clouds, caused by the equal‐V/A representation, are presented for a range of aspect ratios, indentation depths, and ice‐water paths at visible and near‐infrared wavelengths.
MIL03346, the most oxidized Martian meteorite: A first look at spectroscopy, petrography, and mineral chemistry
Authors: Dyar M. Darby , Treiman Allan H. , Pieters Carlé M. , Hiroi Takahiro , Lane Melissa D. , O'Connor Vanessa
Published: September 2005

Meteorite MIL03346, recovered from Antarctica, is a nakhlite: an augite clinopyroxenite inferred to have originated from Mars' surface. MIL03346 contains ∼70% augite and 3% olivine in a fine‐grained mesostasis of basaltic glass, olivine, titanomagnetite, and pyrrhotite. Part of the olivine is altered to fine‐grained ferric clays and oxides: “iddingsite” as described in other nakhlites. Chemical compositions of augite and olivine (FeO/MnO and Fe/Mg) are nearly identical to those of other nakhlites and are consistent with a Martian origin. The augite contains significant Fe3+: ∼24% of total iron by Mössbauer spectroscopy and ∼13% by elemental analyses and crystal chemistry. This proportion of Fe3+ in augite is consistent with high‐temperature equilibration near the QFM oxygen buffer. Thermal emission spectra are similar to those of other nakhlites. Visible to mid‐IR spectra of MIL03346 show the same absorption features as do other nakhlites but at distinctly lower reflectances (which likely represent Fe3+ in augite and magnetite). MIL03346 appears to contain the most Fe3+ of any Martian meteorite studied to date and to have come from the most oxidizing magmatic environment yet reported.
Dielectric properties of self-assembled layers of octadecylamine on mica in dry and humid environments
Authors: Benitez J. J. , de la Fuente O. Rodriguez , Díez-Pérez I. , Sanz F. , Salmeron M.
Published: September 2005

Atomic force microscopy operating in noncontact electrostatic force mode was used to study the interaction of water with films of alkylamines and alkylsilanes on mica. The films efficiently block water adsorption except in exposed mica areas, where it strongly modifies the mobility of surface ions. We also studied the molecular orientation of octadecylamine molecules forming monolayers and multilayer islands. In monolayer films the molecules bind to mica through the amino group, producing a positive contact potential relative to mica (dipole pointing up). In multilayer films the methyl and amino group terminations are exposed in alternating layers that give rise to alternating values of the contact potential. These findings correlate with low and high friction forces measured in the methyl termination and amino terminations.
Models of electrodes and contacts in molecular electronics
Authors: Ke San-Huang , Baranger Harold U. , Yang Weitao
Published: September 2005

Bridging the difference in atomic structure between experiments and theoretical calculations and exploring quantum confinement effects in thin electrodes (leads) are both important issues in molecular electronics. To address these issues, we report here, by using Au-benzenedithiol-Au as a model system, systematic investigations of different models for the leads and the lead-molecule contacts: leads with different cross sections, leads consisting of infinite surfaces, and surface leads with a local nanowire or atomic chain of different lengths. The method adopted is a nonequilibrium Green’s-function approach combined with density-functional theory calculations for the electronic structure and transport, in which the leads and molecule are treated on the same footing. It is shown that leads with a small cross section will lead to large oscillations in the transmission function T(E), which depend significantly on the lead structure (orientation) because of quantum waveguide effects. This oscillation slowly decays as the lead width increases, with the average approaching the limit given by infinite surface leads. Local nanowire structures around the contacts induce moderate fluctuations in T(E), while a Au atomic chain (including a single Au apex atom) at each contact leads to a significant conductance resonance.
Experimental study of a drop bouncing on a wall in a liquid
Authors: Legendre Dominique , Daniel Claude , Guiraud Pascal
Published: September 2005

The behavior of millimetric drops rising in water and bouncing under a horizontal plate is studied using a high-speed video camera. The position and velocity of the center of mass of the drops, as well as their deformation are analyzed. The bouncing is found to be very dissipative, almost 80% of the energy being lost during the interaction with the wall. The deformation of the drop is governed by the balance between its inertia and capillary effects and evolve like a dissipative mass-spring system. The coefficient of restitution is compared to previous experiments done for drops in air, bubbles in water as well as solid spheres in various fluids.
Basic structures of the Shilnikov homoclinic bifurcation scenario
Authors: Medrano-T. Rene O. , Baptista Murilo S. , Caldas Iberê L.
Published: September 2005

We find numerically small scale basic structures of homoclinic bifurcation curves in the parameter space of the Chua circuit. The distribution of these basic structures in the parameter space and their geometrical properties constitute a complete homoclinic bifurcation scenario of this system. Furthermore, these structures and the scenario are theoretically demonstrated to be generic to a large class of dynamical systems that presents, as the Chua circuit, Shilnikov homoclinic orbits. We classify the complexity of primary and subsidiary homoclinic orbits by their order given by the number of their returning loops. Our results confirm previous predictions of structures of homoclinic bifurcation curves and extend this study to high order primary orbits. Furthermore, we identify accumulations of bifurcation curves of subsidiary homoclinic orbits into bifurcation curves of both primary and subsidiary orbits.
Effect of bending and torsion rigidity on self-diffusion in polymer melts: A molecular-dynamics study
Authors: Bulacu Monica , van der Giessen Erik
Published: September 2005

Extensive molecular-dynamics simulations have been performed to study the effect of chain conformational rigidity, controlled by bending and torsion potentials, on self-diffusion in polymer melts. The polymer model employs a novel torsion potential that avoids computational singularities without the need to impose rigid constraints on the bending angles. Two power laws are traditionally used to characterize the dependence of the self-diffusion coefficient on polymer length: D∝N−ν with ν=1 for NNe (reptation regime), Ne being the entanglement length. Our simulations, at constant temperature and density, up to N=250 reveal that, as the chain rigidity increases, the exponent ν gradually increases towards ν=2.0 for NNe. The value of Ne is slightly increased from 70 for flexible chains, up to the point where the crossover becomes undefined. This behavior is confirmed also by an analysis of the bead mean-square displacement. Subsequent investigations of the Rouse modes, dynamical structure factor, and chain trajectories indicate that the pre-reptation regime, for short stiff chains, is a modified Rouse regime rather than reptation.
Effect of capillary and viscous forces on spreading of a liquid drop impinging on a solid surface
Authors: Fedorchenko Alexander I. , Wang An-Bang , Wang Yi-Hua
Published: September 2005

The theoretical models for the deformation of a liquid drop impinging on a solid flat surface at the initial and late stages are proposed. It was found that at the initial stage of the drop impact, the thickness of the emerging film decreases rapidly along its radius r, as r−6, that is similar to the splash jet induced by the blunt-body impact on the liquid surface. The thickness of the film levels off with time due to the viscous force, and the late stage of the drop spreading is controlled by the action of viscous and capillary forces. The influence of the capillary forces is localized in the vicinity of the triple line, and it causes the formation of the thick border (blob) on the edge of the spreading drop. An analytical solution of the model in viscous limit reveals that the minimum film thickness scales as Re−2∕5 and the drop maximum radius in its maximum extension as Re1∕5. The analytical solution for the dynamics of the blob mass growth is also obtained. The kinetic energy of the drop at its maximum extension remains greater than zero in the drop-spreading process even accounting for viscous effect.
High-precision temperature stabilization for sapphire resonators in microwave oscillators
Authors: Boudot R. , Rocher C. , Bazin N. , Galliou S. , Giordano V.
Published: September 2005

In this paper, we propose technical solutions to solve the issue of the thermal stabilization of a room-temperature high-Q whispering gallery mode microwave sapphire resonator. This technology enables the design of very low phase noise microwave sources which can be used as references for phase noise measurements or for high sensitivity radar systems. Nevertheless, the sapphire resonator presents at the ambient temperature a high sensitivity to thermal fluctuations of the order of −70ppm∕K limiting the oscillator stability in the long term. An original resonator thermal configuration has been designed and optimized thanks to finite difference technique simulations. The symmetry of the proposed thermal structure increases the temperature control efficiency. Coupled to a high-resolution electronic temperature controller directly embedded on the microwave cavity, this structure presents a very low sensitivity to the environment thermal fluctuations. This sensitivity is better than −0.05ppm∕K.
Nonlinear acceleration of the electron inertia-dominated magnetohydrodynamic modes due to electron parallel compressibility
Authors: Matsumoto Taro , Naitou Hiroshi , Tokuda Shinji , Kishimoto Yasuaki
Published: September 2005

The behavior of the collisionless magnetohydrodynamics modes is investigated by the gyrokinetic particle simulation in a cylindrical tokamak plasma in the parameter region where the effects of electron inertia and electron parallel compressibility are competitive for magnetic reconnection. Although the linear growth of the m=1 internal kink-tearing mode is dominated by the electron inertia, it is found that the growth rate can be nonlinearly accelerated due to the electron parallel compressibility proportional to the ion sound Larmor radius ρs. It is also found that, as decreasing the electron skin depth δe, the maximum growth rate before the internal collapse saturates independently of the microscopic scales such as δe and ρs. The acceleration of growth rate is also observed in the nonlinear phase of the m=2 double tearing mode.
Regularization of the Alfvén singularity by the Hall effect
Authors: Shiraishi Jun-ya , Ohsaki Shuichi , Yoshida Zensho
Published: September 2005

An ideal magnetohydrodynamics (MHD) equilibrium is described by a system of rather complicated singular differential equations when a flow is included. The so-called Alfvén singularity occurs at the place where the Doppler-shifted Alfvén velocity vanishes. It is due to the vanishing of the highest-order derivative in the differential equation. The Hall effect, working as a singular perturbation to the ideal MHD system, yields a new branch of regular solutions that can smoothly connect two regions separated by the Alfvén singularity. The thickness of the transition layer is of the order of the ion skin depth, the intrinsic length scale brought about by the singular perturbation. The regularization mechanism of the nonlinear Hall effect is not as simple as that of the diffusion effect producing an entropy (viscosity) solution in a viscous fluid. The Hall effect removes the restriction binding the magnetic and flow characteristics, and creates the new branch of regularized solutions. One-dimensional analysis loses sight of this new branch of equilibria.
Magnetic nanowire based high resolution magnetic force microscope probes
Authors: Yang G. , Tang J. , Kato S. , Zhang Q. , Qin L. C. , Woodson M. , Liu J. , Kim J. W. , Littlehei P. T. , Park C. , Zhou O.
Published: September 2005

We report an efficient process for controlled fabrication of high-resolution magnetic force microscope probes using preformed magnetic nanowires. Nickel and cobalt nanowires produced by electrodeposition were directly assembled onto the tip of a commercial atomic force microscope cantilever with controlled orientation and length by dielectrophoresis. The properties of these nanowire-based probes are characterized.
Mechanism and scaling for convection of isolated structures in nonuniformly magnetized plasmas
Authors: Garcia O. E. , Bian N. H. , Naulin V. , Nielsen A. H. , Rasmussen J. Juul
Published: September 2005

Large-scale radial advection of isolated structures in nonuniformly magnetized plasmas is investigated. The underlying mechanism considered is due to the nonlinear evolution of interchange motions, without any presumption of plasma sheaths. Theoretical arguments supported by numerical simulations reveal an inertial scaling for the radial velocity of isolated structures in the ideal limit. This velocity increases as the square root of the structure size relative to the length scale of the magnetic field. The magnitude of the radial advection velocity, as well as the dynamical evolution of the structures, compares favorably with recent experimental measurements of radially propagating blob structures in the scrape-off layer of magnetically confined plasmas.
Multidimensional hydrodynamic plasma-wall model for collisional plasma discharges with and without magnetic-field effects
Authors: Kumar Haribalan , Roy Subrata
Published: September 2005

A numerical model for two-species plasma involving electrons and ions at pressure of 0.1 torr is presented here. The plasma-wall problem is modeled using one- and two-dimensional hydrodynamic equations coupled with Poisson equation. The model utilizes a finite-element algorithm to overcome the stiffness of the resulting plasma-wall equations. The one-dimensional result gives insight into the discharge characteristics including net charge density, electric field, and temporal space-charge sheath evolution. In two dimensions, the plasma formation over a flat plate is investigated for three different cases. The numerical algorithm is first benchmarked with published literature for plasma formed between symmetric electrodes in nitrogen gas. The characteristics of plasma are then analyzed for an infinitesimally thin electrode under dc and rf potentials in the presence of applied magnetic field using argon as a working gas. The magnetic field distorts the streamwise distribution because of a large y-momentum V×B coupling. Finally, the shape effects of the insulator-conductor edge for an electrode with finite thickness have been compared using a 90° shoulder and a 45° chamfer. The 90° chamfer displays a stronger body force created due to plasma in the downward and forward directions.
Nonlinear plasma voids (holes) in a charge-varying dusty plasma
Authors: Tribeche Mouloud , Ait Gougam Leila , Aoutou Kamel , Zerguini Taha Houssine
Published: September 2005

Nonlinear large amplitude plasma voids are investigated in a charge-varying dusty plasma. Numerical solutions of highly nonlinear equations are carried out including dust charging and ion trapping. The results complement previously published results on this problem. It is found that under certain conditions the effect of dust charge variation can be quite important. In particular, it may be noted that the dust charge variation leads to an additional enlargement of the nonlinear plasma voids.
On the stability of medium gap corotating spiral Poiseuille flow
Authors: Meseguer Alvaro , Marques Francisco
Published: September 2005

New features of the linear stability of the spiral Poiseuille flow for a wide range of inner and outer independent rotation speeds of the cylinders and imposed axial pressure gradient are investigated. The analysis is focused on the corotating situation and for a particular radius ratio η=0.5. Unexpected changes in the angle of the bifurcated spiral regimes are found for moderate values of the axial speed as the outer rotation is increased. In particular, tricritical points are detected, where modes associated with azimuthal wave numbers of opposite signs coexist at criticality. The present study is extended to high values of the axial speed of the flow and, to the authors’ knowledge, the complete critical surface in the three-dimensional parameter space is obtained for the first time, providing new results on the behavior of the Tollmien-Schlichting instability. Increasing the rotation rate of the outer cylinder, the Tollmien-Schlichting instability is no longer dominant, resulting in a dramatic decrease in the critical axial Reynolds number. The sudden appearance of turning points in the critical curves recently obtained by other authors is also explained in terms of the geometry of the critical surface.