bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetics as a legal minefield
Authors: QUESTIAUX NICOLE
Published: July 2008

The importance of recent scientific discoveries concerning genetics has a perturbing effect on the legal relations governing society. There is a case for the definition of a special status concerning genetic information – an adaptation of the rules concerning medical information, a proper framework for the activity of bio-banks and a strict definition of the conditions of access to genetic information that allows for identification of a person for non-medical reasons. It would be useful to formulate some proposals of principle to initiate a discussion that must involve the scientific community.
The relationships formed by elderly people: reflecting cultural changes in Europe
Authors: DE JONG GIERVELD JENNY
Published: July 2008

Social and cultural changes that have taken place since the 1960s have had a major impact, in particular on the lives of young adults, but they have also affected the living conditions and opportunities of older adults. The presentation of a selection of relevant data about elderly people's demographic position in different countries of Europe is central in the second section. In the final section results of a Dutch survey are provided and information about new flexible forms of living arrangements when starting a new partner relationship after the age of fifty, are presented and discussed
The Holocaust: remembrance and education
Authors: VON DER DUNK HERMANN
Published: July 2008

The war-generation dealt with the Holocaust as a part of the spectrum of crimes inflicted by the Hitler regime on humanity. The postwar generation, which bore no responsibility, even as neutral witnesses or accomplices, saw it as a special monstrosity; Auschwitz has been integrated into their cultural heritage. In education this means that an obligation of remembrance can provoke reactions of boredom, irritation or worse, since youth is confronted daily with other problems. But remembrance should not be marginal in school history.
Symbolic politics of public time and collective memory. The Polish case
Authors: HALAS ELZBIETA
Published: July 2008

Symbolic construction of the state identity is analysed, along with the symbolic politics of the state toward the past. The great systemic change is conceived as a symbolic transformation where the growth of semiotic behaviour is clearly noticeable. The analysis deals with the changes in the public holidays calendar in Poland: the communist symbolic strategies, symbolic politics of the Solidarity movement and the anti-politics of symbolization in the third Republic of Poland. It discusses problems of the symbolic control of historicity.
Evaluation of a Group Treatment Programme for Parents of Children with Behavioural Disorders
Authors: Connolly Louise , Sharry John , Fitzpatrick Carol
Published: July 2008

This study set out to evaluate the use of a video based parent training programme (The Webster–Stratton Programme) in the management of children referred to child mental health services for treatment of behaviour problems. Following diagnostic assessment children were assigned to one of two groups: parents of both groups completed the parenting programme and, in addition, in the second group the child received an intervention appropriate to his/her clinical presentation. The waiting list control group waited 3 months prior to allocation to either treatment group. Standardised rating scales were administered pre-treatment, post-treatment and at 6-month follow-up to both treatment groups, and at an interval of 3 months to the control group. Improvement was significantly greater in both the treatment groups than in the control group. Parenting training programmes are an effective intervention in the management of clinic-referred children with behaviour disorders.
Hope in adults, ages 20–59, with advanced stage cancer
Authors: Reynolds Mary Anne Hales
Published: July 2008

Objectives:

The diagnosis of terminal cancer begins one of the most complex and challenging individual experiences of human life that requires multiple coping responses, one of those being hope. There are few studies that provide descriptions of hope over time for adults, ages 20–59, with advanced stage cancer. The purpose of this study was to describe hope as defined and experienced by young and middle age adults with advanced stage cancer.

Methods:

This descriptive, longitudinal qualitative research study interviewed 12 hopeful adults with advanced stage cancer once a month for 3 months.

Results:

By definition, this population exhibited high levels of hope at study entry. Hope scores did not change overtime. Four qualities associated with high levels of hope included: reliance on strong spiritual beliefs, maintenance of positive attitudes, accommodation of cancer symptoms, and the presence of supportive resource people. The emphasis or importance of each quality and specific hope related goals were determined and defined individually. Hope goals varied in degree of expectancy and concreteness and require reassessment as conditions change.

Significances of results:

By identifying an individual's hope goals, palliative care clinicians can then plan and implement interventions to move toward that hope goal.
Caregivers’ differing needs across key experiences of the advanced cancer disease trajectory
Authors: DuBenske Lori L. , Wen Kuang-Yi , Gustafson David H. , Guarnaccia Charles A. , Cleary James F. , Dinauer Susan K. , Mctavish Fiona M.
Published: July 2008

Objectives:

Familial caregivers are providing increasing amounts of care to advanced cancer patients. Increased understanding of caregivers’ needs is vital in providing necessary support to lessen caregiver burden and morbidity. Current literature has identified caregiver and patient needs at broad stages of the cancer trajectory; however, such broad stages may be too general to inform a practice of targeting specific interventions when they have the greatest utility. This study examines a variety of particular needs across a number of more discrete illness-related transition experiences specifically in the advanced cancer disease trajectory.

Methods:

One hundred fifty-nine female informal caregivers of people with advanced cancer completed a needs assessment survey.

Results:

Analyses of these cross-sectional retrospective-report data reveal that cancer caregiver needs vary across specific key experiences occurring within the broader stages of illness identified by current literature. Furthermore, caregivers have unique needs during bereavement.

Significance of results:

Although the sample characteristics are demographically limited, this study provides preliminary evidence that the broad stages are not specific enough increments for effectively examining caregiver needs and supports the need for more precise distribution of cancer-related information at more discrete times in the illness course.
Physical description of an upwelling filament west of Cape St. Vincent in late October 2004
Authors: Sánchez R. F. , Relvas P. , Martinho A. , Miller P.
Published: July 2008

The present paper describes the physical characteristics of an upwelling filament off Cape St. Vincent (southern Iberia) in October 2004, based on remote sensing, hydrographic, ADCP and wind data. It was associated with a meandering jet similar to eastern Pacific or Canary filaments, though its dynamical features were weaker as a result of the surface‐trapped (top 100 m) and weak horizontal density gradients. The filament transported 0.9 Sv of coastal water offshore, of which 8% was due to Ekman transport; it formed following the destabilization of an alongshore equatorward upwelling jet close to the cape. The filament was structurally asymmetric, with anticyclonic geostrophic vorticity to the north and more strongly cyclonic to the south, as a result of the meanders and existing eddies. The filament comprised a sequence of cold, submesoscale (∼30 km diameter) cyclones. Vertical velocities of ±15 m·d−1 were associated with meanders of the jet. The surface and subsurface circulation was coupled. At middepths (90–150 m) anticyclonic recirculation of northern water seemed associated with a separated, older upwelling jet. Mediterranean Water (MW) was present below 350 dbar as a topographically steered undercurrent and a meddy‐cyclone dipole. These undercurrents contributed to the formation of the October filament through baroclinic instability associated with the enhanced vertical shear.
Aerosol optical depths over North Africa: 2. Modeling and model validation
Authors: Greed Glenn , Haywood Jim M. , Milton Sean , Keil Andreas , Christopher Sundar , Gupta Pawan , Highwood Eleanor J.
Published: July 2008

An operational dust forecasting model is developed by including the Met Office Hadley Centre climate model dust parameterization scheme, within a Met Office regional numerical weather prediction (NWP) model. The model includes parameterizations for dust uplift, dust transport, and dust deposition in six discrete size bins and provides diagnostics such as the aerosol optical depth. The results are compared against surface and satellite remote sensing measurements and against in situ measurements from the Facility for Atmospheric Airborne Measurements for a case study when a strong dust event was forecast. Comparisons are also performed against satellite and surface instrumentation for the entire month of August. The case study shows that this Saharan dust NWP model can provide very good guidance of dust events, as much as 42 h ahead. The analysis of monthly data suggests that the mean and variability in the dust model is also well represented.
Astronomically modulated Neogene sediment records from the South China Sea
Authors: Tian Jun , Zhao Quanhong , Wang Pinxian , Li Qianyu , Cheng Xinrong
Published: July 2008

General global cooling over the Neogene has been modulated by changes in Earth's orbital parameters. Investigations of deep‐sea sediment sequences show that various orbital cycles can dominate climate records for different latitudes or for different time intervals. However, a comprehensive understanding of astronomical imprints over the entire Neogene has been elusive because of the general absence of long, continuous records extending beyond the Pliocene. We present benthic foraminiferal δ18O and δ13C records over the past 23 Ma at Ocean Drilling Program Site 1148 in the northern South China Sea and construct an astronomically tuned timescale (TJ08) for these records based on natural gamma radiation and color reflectance data at this site. Our results show that a 41 ka cycle has dominated sediment records at this location over the Neogene, displaying a linear response to orbital forcing. A 100 ka cycle has also been significant. However, it is correlated nonlinearly with Earth's orbital variations at the 100 ka band. The sediment records also display a prominent 405 ka cycle. Although this cycle was coherent with orbital forcing during the Oligocene and the early Miocene, it was not coherent with Earth's orbital variations at the 405 ka band over the whole Neogene. Amplification of Northern Hemisphere and Southern Hemisphere glaciation since the middle Miocene may be responsible for this change in sedimentary response. Our benthic foraminifera δ18O and δ13C records further exhibit amplitude variations with longer periods of 600, 1000, 1200, and 2400 ka. Apparently, these cycles are nonlinear responses to insolation forcing.
Fan‐shaped antennas: Realization of wideband characteristics and generation of stop bands
Authors: Nakano H. , Morishita K. , Iitsuka Y. , Mimaki H. , Yoshida T. , Yamauchi J.
Published: July 2008

This paper presents four fan‐shaped antennas: U.S.‐FAN, CROSS‐FAN, CROSS‐FAN‐W, and CROSS‐FAN‐S. Each of these antennas stands upright above a ground plane, and has edges expressed by an exponential function and a circle function. The four antennas are investigated using frequencies from 1.5 GHz to 11 GHz. The CROSS‐FAN is found to have a lower VSWR over a wide frequency band compared to the U.S.‐FAN. The CROSS‐FAN‐W and CROSS‐FAN‐S are modified versions of the CROSS‐FAN, each designed to have a stop band (a high VSWR frequency range) for interference cancellation. The stop band for the CROSS‐FAN‐W is controlled by a wire (total length 4Lwire) that connects the fan‐shaped elements. The center frequency of the stop band fstop is close to the frequency corresponding to a wire segment length Lwire of half the wavelength. It is also found that the stop band in the CROSS‐FAN‐S can be controlled by four slots, one cut into each of the fan‐shaped elements. The center frequency of the stop band fstop is close to the frequency corresponding to a slot length Lslot of one‐quarter of the wavelength. Experimental work is performed to confirm the theoretical results, using the CROSS‐FAN‐S.
Infrasound from hurricanes: Dependence on the ambient ocean surface wave field
Authors: Hetzer Claus H. , Waxler Roger , Gilbert Kenneth E. , Talmadge Carrick L. , Bass Henry E.
Published: July 2008

Infrasound signals in the microbarom band (about 0.2 Hz) generated by hurricanes often do not appear to originate near the eye where the winds are strongest. This paper suggests that conditions conducive to microbarom (and microseism) generation can occur along the trailing periphery of the storm through the interaction of the storm‐generated wavefield with the ambient swell field, resulting in detection bearings that vary from the center of the storm by up to 20 degrees. Infrasound data from Typhoon Usagi (2007) is presented that supports this theory.
Shifting climate zones for Australia's tropical marine ecosystems
Authors: Lough J. M.
Published: July 2008

Sea surface temperatures (SSTs) are significantly warming along the northwest (NW) and northeast (NE) coasts of Australia ‐ regions containing well‐protected and internationally significant tropical marine ecosystems. The magnitude and spatial distribution of observed warming of annual, maximum and minimum SSTs is examined, 1950–2007. Observed warming is comparable along the NE and NW coasts although greater along the NE coast south ∼15°S, greater at higher than lower latitudes, and greater for annual minimum than annual maximum SSTs. Average climate zones have also shifted >200 km south along the NE coast and about half that distance along the NW coast. If current trends continue, annual average SSTs in northern parts could be ∼0.5°C warmer and those of more southern parts ∼2.0°C warmer within the next 100 years. These rapid changes in oceanic climate are already causing responses in Australia's tropical marine ecosystems and these responses, if present rates of warming continue, can only intensify.
Mechanism of the northward propagation of mesoscale convective systems observed on 15 June 2005 during PALAU2005
Authors: Moteki Qoosaku , Shirooka Ryuichi , Kubota Hisayuki , Ushiyama Tomoki , Reddy Krishnaredikari Krishna , Yoneyama Kunio , Katsumata Masaki , Sato Naoki , Yasunaga Kazuaki , Yamada Hiroyuki , Geng Biao , Fujita Mikiko , Yoshizaki Masanori , Uyeda Hiroshi , Chuda Takashi
Published: July 2008

This paper describes the structure and evolution of northward propagating mesoscale convective systems (MCSs) observed over the tropical western Pacific on 15 June 2005. A wedge‐shaped convective cloud area, consisting of three groups of MCSs, was generated near the equator to the north of New Guinea at around 0000 LST on 15 June, and one of the groups of MCSs propagated toward Palau (7°–8°N). Dropsonde analysis revealed that the MCSs developed at the northern edge of a cold air mass that had a horizontal scale of more than 400 km. Global objective analysis data from the Japan Meteorological Agency showed that the cold air mass observed by the dropsonde analysis originated in a land breeze from New Guinea. The cold air mass was initially formed by cold advection from the south and was maintained by cooling with the MCSs. When the initial MCSs were generated along the land‐breeze front, an easterly wave, which was accompanied by low‐level southerly wind and a low‐pressure area, was located near Palau. The cold air mass associated with the land breeze between 132° and 137°E was locally extended toward the center of the low‐pressure area. The results suggest that the easterly wave located around Palau helped locally promote northward cold advection from New Guinea, inducing the long‐distance northward propagation of MCSs generated along the land‐breeze front.
A novel non‐antibacterial, non‐chelating hydroxypyrazoline derivative of minocycline inhibits nociception and oedema in mice
Authors: Bastos L F S , Angusti A , Vilaça M C , Merlo L A , Nascimento E B , Rocha L T S , Godin A M , Solano A G R , Jarussophon S , Nunan E A , Konishi Y , Coelho M M
Published: July 2008

Background and purpose:

Many in vitro and fewer in vivo studies have shown that tetracyclines present anti‐inflammatory activity. We investigated if a novel non‐antibacterial, non‐chelating hydroxypyrazoline derivative of minocycline, 12S‐hydroxy‐1,12‐pyrazolinominocycline (PMIN), also induced antinociceptive and anti‐inflammatory effects.

Experimental approach:

Antibacterial effects against a minocycline‐sensitive Staphylococcus aureus strain were evaluated by applying a cylinder‐plate agar diffusion technique. Antibacterial effects of diluted serum from mice pre‐treated with minocycline or PMIN were also evaluated. Ca2+ binding activity was assessed by spectrophotometry. Formalin‐induced nociceptive responses and carrageenan‐induced paw oedema were evaluated in mice. The rota‐rod apparatus was used to evaluate motor coordination.

Key results:

Minocycline, but not PMIN, inhibited bacterial growth. Serum from mice treated with minocycline, but not with PMIN, also induced such an effect. The UV absorption spectrum of solutions of minocycline, but not those of PMIN, was markedly changed in the presence of Ca2+. Minocycline or PMIN inhibited both phases of formalin‐induced nociception and carrageenan‐induced paw oedema. It is unlikely that antinociception resulted from lack of motor coordination, as tetracycline did not impair the performance of mice on the rotating rod.

Conclusions and implications:

These results indicate that inhibition of nociception and oedema by tetracyclines is neither necessarily linked to antibacterial nor to Ca2+chelating activities. This study supports the evaluation of the potential usefulness of PMIN in the treatment of painful and inflammatory diseases, as its lack of antibacterial and Ca2+chelating activities might confer greater safety over conventional tetracyclines.

British Journal of Pharmacology (2008) 155, 714–721; doi:10.1038/bjp.2008.303; published online 28 July 2008
Antinociceptive effects of tetrazole inhibitors of endocannabinoid inactivation: cannabinoid and non‐cannabinoid receptor‐mediated mechanisms
Authors: Maione S , Morera E , Marabese I , Ligresti A , Luongo L , Ortar G , Di Marzo V
Published: July 2008

Background and purpose:

Tetrazoles were recently developed as inhibitors of the cellular uptake of the endocannabinoid anandamide or of its hydrolysis by fatty acid amide hydrolase (FAAH), but were proposed to act also on non‐endocannabinoid‐related serine hydrolases.

Experimental approach:

We tested, in a model of inflammatory pain induced in mice by formalin, five chemically similar inhibitors: (i) OMDM119 and OMDM122, two potent carbamoyl tetrazole FAAH inhibitors with no effect on anandamide uptake; (ii) LY2183240, a carbamoyl tetrazole with activity as both FAAH and uptake inhibitor; (iii) OMDM132, a non‐carbamoyl tetrazole with activity only as uptake inhibitor and iv) OMDM133, a non‐carbamoyl tetrazole with no activity at either FAAH or uptake.

Results:

All compounds (2.5–10 mg kg−1, i.p.) inhibited the second phase of the nocifensive response induced by intraplantar injection of formalin. The effects of OMDM119, OMDM122 and OMDM133 were not antagonized by pretreatment with cannabinoid CB1 receptor antagonists, such as rimonabant or AM251 (1–3 mg kg−1, i.p.). The effects of LY2183240 and OMDM132 were fully or partially antagonized by rimonabant, respectively, and the latter compound was also partly antagonized by the CB2 receptor antagonist, AM630.

Conclusions and implications:

(i) non‐FAAH hydrolases might be entirely responsible for the antinociceptive activity of some, but not all, tetrazole FAAH inhibitors, (ii) the presence of a carbamoylating group is neither necessary nor sufficient for such compounds to act through targets other than FAAH and (iii) inhibition of anandamide uptake is responsible for part of this antinociceptive activity, independently of effects on FAAH.

British Journal of Pharmacology (2008) 155, 775–782; doi:10.1038/bjp.2008.308; published online 28 July 2008
The dewetting dynamics of the polymer thin film by solvent annealing
Authors: Xu Lin , Shi Tongfei , An Lijia
Published: July 2008

The slippage effect of the polymer chains is investigated in the dewetting process of the polymer solution film. The solvent-induced dewetting is used in our experiments to study the dynamics of hole growth in the dewetting process of the polymer solution film. Our results show that in the case of the low molecular weight polystyrene (PS) film, the slippage effect of the polymer chains is not displayed and the radius of the holes is R∼exp(t∕τ); in the case of the higher molecular weight PS film, the slippage effect of the polymer chain is not valid in the case of the thin film and that is valid in the case of the thick film, and the dynamic process of hole growth divides into three stages (R∼t, and then R∼tx (2∕3<x<1), finally, R∼t). Besides, the solvent and substrate properties also influence the dewetting dynamics of the polymer solution film.
Ambipolar transport behavior in In2O3/pentacene hybrid heterostructure and their complementary circuits
Authors: Dhananjay  , Ou Chun-Wei , Yang Chuan-Yi , Wu Meng-Chyi , Chu Chih-Wei
Published: July 2008

In this Letter, ambipolar transport properties of a bilayer of In2O3 and a pentacene heterostructure have been realized. While In2O3 thin film transistors exhibited a n-channel behavior, pentacene presumed p-channel characteristics on bare SiO2∕p-Si substrates. However, when a bilayer of In2O3/pentacene was realized on the gate dielectrics, the hybrid structure exhibited both n- and p-channel conductions, depicting an ambipolar transistor behavior. When two identical ambipolar transistors were integrated to establish an inverter structure, a voltage gain of 10 was obtained. The results indicate that these heterostructures can be utilized for the complementary circuits.
Study of anomalous infrared properties of nanomaterials through effective medium theory
Authors: Su Zhang-Fei , Sun Shi-Gang , Wu Chen-Xu , Cai Zhi-Ping
Published: July 2008

Effective medium theory is introduced into a three-layer model to study the anomalous IR properties of nanostructured Pt films. A composite system is set up for the nanostructured film together with adsorbates and water around it. The anomalous IR spectral features, which exhibit a transition from enhanced (or normal) IR absorption to Fano-type bipolar line shape and, finally, to enhanced anomalous IR absorption (the abnormal infrared effects) along with the change in structure and size of nanomaterials, as observed through experiments for CO molecule adsorption, are elucidated by an increase in the volume fraction of metal in the composite system and the effective thickness of the composite system. The theoretical simulation results illustrate that the spectral line shape of IR absorption depends strongly on the volume fraction of metal, while the intensity of the IR band is directly proportional to the effective thickness. This study has revealed, through a physical optical aspect of interaction of CO molecules with nanostructured metal films, one of the possible origins of anomalous IR properties and has shed light on interpreting the peculiar properties of nanomaterials.
Low voltage operating InGaZnO4 thin film transistors using high-k MgO–Ba0.6Sr0.4TiO3 composite gate dielectric on plastic substrate
Authors: Kim Dong Hun , Cho Nam Gyu , Kim Ho-Gi , Kim Hyun-Suk , Hong Jae-Min , Kim Il-Doo
Published: July 2008

The authors report on the dielectric and leakage current properties of room temperature grown MgO-Ba0.6Sr0.4TiO3 (MgO-BST) composite thin films to be utilized InGaZnO4 thin films transistors (TFTs) fabricated on a polyethylene terephthalate (PET) substrate. The InGaZnO4 TFTs with MgO-BST gate dielectrics exhibited low operation voltage of 4V, high on/off current ratio of 4.13×106, and high field effect mobility of 10.86cm2∕Vs. These results verify that a room temperature grown MgO-BST gate dielectric is a good candidate for producing high performance InGaZnO4 TFTs on plastic substrates.
Preselectable integer quantum conductance of electrochemically fabricated silver point contacts
Authors: Xie F.-Q. , Maul R. , Brendelberger S. , Obermair Ch. , Starikov E. B. , Wenzel W. , Schön G. , Schimmel Th.
Published: July 2008

The controlled fabrication of well-ordered atomic-scale metallic contacts is of great interest: it is expected that the experimentally observed high percentage of point contacts with a conductance at noninteger multiples of the conductance quantum G0=2e2∕h in simple metals is correlated to defects resulting from the fabrication process. Here we demonstrate a combined electrochemical deposition and annealing method that allows the controlled fabrication of point contacts with preselectable integer quantum conductance. The resulting conductance measurements on silver point contacts are compared with tight-binding-like conductance calculations of modeled idealized junction geometries between two silver crystals with a predefined number of contact atoms.
Reduced efficiency roll-off in phosphorescent organic light emitting diodes at ultrahigh current densities by suppression of triplet-polaron quenching
Authors: Zang F. X. , Sum T. C. , Huan A. C. H. , Li T. L. , Li W. L. , Zhu Furong
Published: July 2008

High-performance phosphorescent organic light emitting devices with reduced efficiency roll-off at ultrahigh current densities were realized. The devices were Ir(ppy)3-based phosphorescent organic light emitting diodes that employed 1,3-bis[2-(2,2′-bipyridine-6-yl)-1,3,4-oxadiazo-5-yl]benzene as a high mobility electron transfer layer. The device’s brightness was enhanced while the efficiency roll-off was reduced. The device exhibits high current efficiency (21cd∕A) at high brightness (80000cd∕m2), with a maximum luminescence of 136000cd∕m2 at over 1A∕m2 (with an efficiency of 13cd∕A). This reduction in efficiency roll-off is attributed to the suppression of the triplet-polaron quenching rate through balancing the charge carrier ratio in the device.
Compression of trapped positrons in a single particle regime by a rotating electric field
Authors: Greaves R. G. , Moxom J. M.
Published: July 2008

Positrons confined in a cylindrical Penning trap are compressed radially by applying a rotating electric field. Previous experiments were conducted with large numbers of positrons in the plasma state. Compression of small numbers of positrons in the single particle regime is reported for the first time. For low values of applied rf amplitude, the compression occurs in a narrow band of frequencies centered on the axial bounce frequency. For larger amplitudes, the compression extends to a broad range of frequencies below the bounce frequency. Under certain conditions, very rapid compression can be obtained and central density doubling times of only a few milliseconds have been observed. Possible models for the effect are discussed. Potential application to the production of brightness enhanced positron beams is described.
Emission color tunable light-emitting diodes composed of InGaN multifacet quantum wells
Authors: Funato M. , Hayashi K. , Ueda M. , Kawakami Y. , Narukawa Y. , Mukai T.
Published: July 2008

We demonstrate that the apparent emission colors of InGaN-based light-emitting diodes using microstructured multifacet quantum wells as active layers can externally be controlled over a wide spectral range that encompasses green to blue or white at a color temperature of 4000K to blue along the Planckian locus. The controllability relies on facet-dependent polychromatic emissions. The pulsed current operation with the appropriate duties varied their relative intensities and the consequent apparent colors without seriously affecting the total number of emitted photons, particularly for the blue to green variation.
X-ray magnetic circular dichroism in reflection geometry: A tool for investigating surface magnetism in thin films
Authors: Valencia S. , Gaupp A. , Gudat W. , Abad Ll. , Balcells Ll. , Martinez B.
Published: July 2008

Surface and interface magnetisms in oxide thin films and heterostructures have been a recurrent topic during the past years due to their relevance in the implementation of magnetoelectronic devices. Magneto-optical techniques, such as x-ray magnetic circular dichroism, turn out to be a very efficient tool to study surface magnetism due to their sensitivity to magnetic and chemical variations across the sample depth. Nevertheless, the application of the sum rules for the determination of the spin magnetic moment might lead to uncertainties as large as 40%. To overcome this problem we present an alternative approach consisting in using x-ray magnetic circular dichroism in reflection geometry. Data analysis by using a computer code based on a 4×4 matrix formalism indicates that surface and interface roughnessas are of major relevance for a proper description of the experimental data and a correct interpretation of the results. By using such an approach, we discuss the presence of a narrow surface region with strongly depressed magnetic properties in La2∕3Ca1∕3MnO3 thin films.
Study of metal-related deep-level defects in germanide Schottky barriers on n-type germanium
Authors: Simoen E. , Opsomer K. , Claeys C. , Maex K. , Detavernier C. , Van Meirhaeghe R. L. , Clauws P.
Published: July 2008

Deep levels have been studied in n-type germanium subjected to Co, Fe, Cu, Cr, and Pt germanidation in the temperature range between 300 and 700°C by deep-level transient spectroscopy (DLTS). It is shown that most DLTS peaks can be assigned to acceptor levels of substitutional metal atoms. However, while in the case of Co, Fe, and Cu we have clear evidence of the indiffusion of the respective metals during the germanidation step, contamination with fast-diffusing Cu dominates the spectra for the Cr and Pt samples. At the same time, the occurrence of minority carrier traps during a bias pulse in forward operation is demonstrated and the interpretation of the corresponding peaks is discussed.
Static properties of small Josephson tunnel junctions in a transverse magnetic field
Authors: Monaco R. , Aaroe M. , Mygind J. , Koshelets V. P.
Published: July 2008

The magnetic field distribution in the barrier of small planar Josephson tunnel junctions is numerically simulated in the case when an external magnetic field is applied perpendicular to the barrier plane. The simulations allow for heuristic analytical solutions for the Josephson static phase profile from which the dependence of the maximum Josephson current on the applied field amplitude is derived. The most common geometrical configurations are considered and, when possible, the theoretical findings are compared with the experimental data.
Solvation-induced cluster anion core switching from NNO2−(N2O)n−1 to O−(N2O)n
Authors: Pichugin Kostyantyn , Grumbling Emily , Velarde Luis , Sanov Andrei
Published: July 2008

We report a photoelectron imaging study of the [O(N2O)n]−, 0≤n≤9, cluster anions generated via electron bombardment of a pulsed supersonic expansion of pure N2O gas. Depending on cluster size, the photoelectron image features and spectral trends, examined at 355 and 266 nm, give evidence of two dominant core-anion structures, corresponding to the NNO2−(N2O)n−1 and O−(N2O)n cluster anions. In agreement with previous studies, the n=1 anion has a covalently bound (Y-shaped) NNO2− structure. The NNO2− core is also found to persist in the larger clusters, up to n=3. However, for n≥4 (and up to at least n=9) signatures of an O− core are predominantly observed. Photofragmentation studies at 355 nm support these results.
Quasielectrostatic whistler wave radiation from the hot electron emission of a laser-produced plasma
Authors: Vincena Stephen , Gekelman Walter , Van Zeeland M. A. , Maggs James , Collette Andrew
Published: July 2008

Measurements are presented of radiated wave electric fields which result from the creation of a dense, laser-produced plasma within a large, uniform background magnetoplasma. The radiated field patterns are consistent for waves propagating along the quasielectrostatic branch of the whistler wave dispersion curve calculated from the background plasma parameters. The energy source of these waves coincides with an observed energetic tail electron population escaping the laser-produced plasma. A prominent feature of the radiated electric fields is a bipolar spike in both time and space, with a cross-field size near that of the initial escaping electron burst and a duration equivalent to one oscillation at the lower hybrid frequency within the background plasma. Additionally, time-windowed snapshots of the whistler wave radiation patterns are shown to provide a remote diagnostic of the cross-field speed of the laser-produced plasma.
Dependence of ferromagnetic properties on conductivity for As-doped p-type (Zn0.93Mn0.07)O layers
Authors: Lee Sejoon , Shon Yoon , Won Kang Tae , Yoon Chong S. , Kim Eun Kyu , Kim Deuk Young
Published: July 2008

The As-doped p-type (Zn0.93Mn0.07)O layers show a strong dependence of their ferromagnetic properties on the hole conductivity that were controlled through the modification of negative background-charge density by changing the oxygen partial pressure during the initial growth stage before As doping. Curie temperature and spontaneous magnetization were observed to be increased as the hole conductivity increases. This result was confirmed to originate from stabilizations of incorporated Mn2+ ions and doped As acceptors, which can give rise to long-range ferromagnetic coupling.
Development of a low-temperature photoelectron spectroscopy instrument using an electrospray ion source and a cryogenically controlled ion trap
Authors: Wang Xue-Bin , Wang Lai-Sheng
Published: July 2008

The ability to control ion temperatures is critical for gas phase spectroscopy and has been a challenge in chemical physics. A low-temperature photoelectron spectroscopy instrument has been developed for the investigation of complex anions in the gas phase, including multiply charged anions, solvated species, and biological molecules. The new apparatus consists of an electrospray ionization source, a three dimensional (3D) Paul trap for ion accumulation and cooling, a time-of-flight mass spectrometer, and a magnetic-bottle photoelectron analyzer. A key feature of the new instrument is the capability to cool and tune ion temperatures from 10to350K in the 3D Paul trap, which is attached to the cold head of a closed cycle helium refrigerator. Ion cooling is accomplished in the Paul trap via collisions with a background gas and has been demonstrated by observation of complete elimination of vibrational hot bands in photoelectron spectra of various anions ranging from small molecules to complex species. Further evidence of ion cooling is shown by the observation of H2-physisorbed anions at low temperatures. Cold anions result in better resolved photoelectron spectra due to the elimination of vibrational hot bands and yield more accurate energetic and spectroscopic information. Temperature-dependent studies are made possible for weakly bonded molecular and solvated clusters, allowing thermodynamic information to be obtained.
On-chip integration of high-frequency electron paramagnetic resonance spectroscopy and Hall-effect magnetometry
Authors: Quddusi H. M. , Ramsey C. M. , Gonzalez-Pons J. C. , Henderson J. J. , del Barco E. , de Loubens G. , Kent A. D.
Published: July 2008

A sensor that integrates high-sensitivity micro-Hall effect magnetometry and high-frequency electron paramagnetic resonance spectroscopy capabilities on a single semiconductor chip is presented. The Hall-effect magnetometer (HEM) was fabricated from a two-dimensional electron gas GaAs∕AlGaAs heterostructure in the form of a cross, with a 50×50μm2 sensing area. A high-frequency microstrip resonator is coupled with two small gaps to a transmission line with a 50Ω impedance. Different resonator lengths are used to obtain quasi-TEM fundamental resonant modes in the frequency range 10–30GHz. The resonator is positioned on top of the active area of the HEM, where the magnetic field of the fundamental mode is largest, thus optimizing the conversion of microwave power into magnetic field at the sample position. The two gaps coupling the resonator and transmission lines are engineered differently—the gap to the microwave source is designed to optimize the loaded quality factor of the resonator (Q⩽150) while the gap for the transmitted signal is larger. This latter gap minimizes losses and prevents distortion of the resonance while enabling measurement of the transmitted signal. The large filling factor of the resonator permits sensitivities comparable to that of high-quality factor resonant cavities. The integrated sensor enables measurement of the magnetization response of micron scale samples upon application of microwave fields. In particular, the combined measurement of the magnetization change and the microwave power under cw microwave irradiation of single crystal of molecular magnets is used to determine of the energy relaxation time of the molecular spin states. In addition, real-time measurements of the magnetization dynamics upon application of fast microwave pulses are demonstrated.
Increased robustness for fluidic self-assembly
Authors: Krishnan Mekala , Tolley Michael T. , Lipson Hod , Erickson David
Published: July 2008

Self-assembly methods have been developed at the micro- and nanoscale to create functional structures from subelements stochastically dispersed in a fluid. Self-assembly paradigms have limitations in terms of achievable complexity of the final structure, ability to perform error correction, and scalability. Fluidic self-assembly attempts to overcome these limitations by incorporating a controlled flow structure and/or complex geometric interactions to improve the assembly rate and the specificity of the final positioning. Since the initial position and orientation of a subelement in a stochastic system are indeterminate, the most robust of these schemes are those for which the dependence on the initial condition will be the weakest. In this paper we develop an analytical/numerical model for the fluid forces and torques on a two-dimensional subelement involved in a fluidic self-assembly process and describe the translational and rotational motions of the element due to these forces. We use this model to determine optimal subelement shapes and flow conditions that lead to successful assembly over the broadest range of initial conditions. We quantify the degree to which assembly has been successful by introducing two docking parameters that are descriptive of how close the final subelement position is to the ideal case. Robust self-assembly schemes were developed for the assembly of different tile shapes. This approach to evaluate a self-assembly process based on the final subelement position can be applied to other fluidic self-assembly techniques.
A simple large-scale droplet generator for studies of inkjet printing
Authors: Castrejón-Pita J. R. , Martin G. D. , Hoath S. D. , Hutchings I. M.
Published: July 2008

A simple experimental device is presented, which can produce droplets on demand or in a continuous mode and provides a large-scale model for real inkjet printing systems. Experiments over different regimes of Reynolds and Weber number were carried out to test the system. The ranges of Reynolds and Weber numbers were adjusted by modifying the liquid properties or the jetting parameters. Reynolds numbers from 5.6 to 1000 and Weber numbers from 0.5 to 160 were obtained using water/glycerol mixtures in the drop-on-demand mode and Reynolds numbers from 30 to 5500 and Weber numbers from 20 to 550 for the continuous jet mode. The nozzle diameter can be varied from 0.15to3.00mm and drop velocities were achieved in the range from 0.3to6.0m∕s depending on the jetting parameters and the driving mode. Keywords: Droplet, printer nozzle, drop on demand and continuous jet.
Critical Δ′ for stability of viscoresistive tearing modes
Authors: Grasso D. , Hastie R. J. , Porcelli F. , Tebaldi C.
Published: July 2008

An analytic expression for the stability threshold of linear tearing modes is derived. The magnetized plasma is described in terms of a standard viscoresistive magnetohydrodynamic model. The analytic derivation requires an extension of the standard layer equation that represents an approximation of the full model in the vicinity of the reconnecting layer. The analytic result is checked against numerical simulations, showing excellent agreement.
Origin of high mobility within an amorphous polymeric semiconductor: Space-charge-limited current and trap distribution
Authors: Chung Dae Sung , Lee Dong Hoon , Yang Chanwoo , Hong Kipyo , Park Chan Eon , Park Jong Won , Kwon Soon-Ki
Published: July 2008

To elucidate the origin of the high field-effect mobility (≈0.02cm2∕Vs) of amorphous poly[(1,2-bis-(2′-thienyl)vinyl-5′,5″-diyl)-alt-(9,9-dioctyldecylfluorene-2,7-diyl], we investigated the current density–voltage (J-V) and mobility–voltage (μ-V) relationships as a function of temperature. By using the power law model and the Gaussian hopping model, we determined a characteristic trap energy of 67meV, an energetic disorder parameter of 64meV, and a total trap density of 2.5×1016cm−3, comparable to that of poly(3-hexylthiophene). We conclude that the relatively low trap density, which originates from the grain-boundary-free amorphous nature of the semiconductor, enables this high field-effect mobility.
Size correction in ultrafast laser processing of fused silica by temporal pulse shaping
Authors: Mermillod-Blondin A. , Mauclair C. , Rosenfeld A. , Bonse J. , Hertel I. V. , Audouard E. , Stoian R.
Published: July 2008

Laser structuring of bulk dielectric materials involves focusing through air-dielectric interfaces, which is prone to induce spherical aberrations. This elongates the energy deposition volume and restricts the processing accuracy at large focusing depths. Although spatial phase corrections are commonly applied to correct wavefront distortions, we show that temporal forming of ultrafast laser pulses achieves comparable counteracting function, limiting the spatial extent while creating a dominant region of positive index change. We indicate the role of reduced nonlinearity in plasma formation as a control factor which couples the spatial and temporal responses of the material.
Highly efficient polarized polymer light-emitting diodes utilizing oriented films of β-phase poly(9,9-dioctylfluorene)
Authors: Misaki Masahiro , Chikamatsu Masayuki , Yoshida Yuji , Azumi Reiko , Tanigaki Nobutaka , Yase Kiyoshi , Nagamatsu Shuichi , Ueda Yasukiyo
Published: July 2008

Uniaxially oriented films of β-phase poly(9,9-dioctylfluorene) (PFO) were realized by a friction-transfer technique followed by thermal annealing and vapor treatments. Absorption and photoluminescence (PL) spectra show the characteristics of β-phase: an additional absorption peak at 433nm and redshifted PL peaks compared with those of the usual nematic (N) phase. We fabricated polarized polymer light-emitting diodes utilizing oriented films of β-phase PFO. Highly polarized β-phase emission with an integrated polarization ratio of 51 was observed from the devices. The efficiency of the devices based on β-phase reached 2.0cd∕A, which is two times higher than that based on N-phase.
Evolution of the nanostructure of deposits grown by electron beam induced deposition
Authors: Li Juntao , Toth Milos , Tileli Vasiliki , Dunn Kathleen A. , Lobo Charlene J. , Thiel Bradley L.
Published: July 2008

Environmental scanning electron microscopy (ESEM) was used to perform electron beam induced deposition (EBID) using a WF6 precursor. The deposits consist of WO3 nanocrystals embedded in an amorphous matrix. Oxide formation is attributed to residual oxidizers present in the ESEM chamber during EBID. Under conditions of fixed low electron flux, the WO3 grain size and the degree of deposit crystallinity increase with time. These changes correlate with the degree of electron energy deposition into the material during growth, indicating that electron beam induced modification of as-grown material is significant in controlling the nanostructure and functionality of materials fabricated by EBID.
Ferromagnetism in CuO–ZnO multilayers
Authors: Sudakar C. , Padmanabhan K. , Naik R. , Lawes G. , Kirby B. J. , Kumar Sanjiv , Naik V. M.
Published: July 2008

We investigated the magnetic properties of CuO–ZnO heterostructures to elucidate the origin of the ferromagnetic signature in Cu doped ZnO. The CuO and ZnO layer thickness were varied from 15 to 150 nm and from 70to350nm, respectively. Rutherford backscattering experiments showed no significant diffusion of either Cu in ZnO or Zn in CuO layers. Magnetic measurements indicate ferromagnetism at 300K, which depends on the CuO particle size, but not on the CuO–ZnO interfacial area. Polarized neutron reflectometry measurements show that the observed magnetization cannot be accounted for solely by spins localized near the CuO–ZnO interface or in the CuO layer.
Micromagnetic simulation of domain wall dynamics in Permalloy nanotubes at high frequencies
Authors: Betancourt I. , Hrkac G. , Schrefl T.
Published: July 2008

The formation and motion of a single cross-tie type domain wall (DW) was studied in a Ni80Fe20 Permalloy nanotube of 50 nm thickness and 500 nm length by means of micromagnetic simulations. Circular magnetization curves, calculated with circumferential ac magnetic fields applied on the nanotube, showed that the propagation of the DW along the nanotube length occurred for hrms values as low as 166 A/m at a frequency of 250 MHz. In general, the observed DW motion exhibited an out-of-phase oscillating character, relative to the applied hac field, with a normalized phase shift of 0.20 being independent of hrms. The DW damping was observed at 10 GHz.
Polarization-matched GaInN∕AlGaInN multi-quantum-well light-emitting diodes with reduced efficiency droop
Authors: Schubert Martin F. , Xu Jiuru , Kim Jong Kyu , Schubert E. Fred , Kim Min Ho , Yoon Sukho , Lee Soo Min , Sone Cheolsoo , Sakong Tan , Park Yongjo
Published: July 2008

Blue multi-quantum-well light-emitting diodes (LEDs) with GaInN quantum wells and polarization-matched AlGaInN barriers are grown by metal-organic chemical vapor deposition. The use of quaternary alloys enables an independent control over interface polarization charges and bandgap and has been suggested as a method to reduce electron leakage from the active region, a carrier loss mechanism that can reduce efficiency at high injection currents—an effect known as the efficiency droop. The GaInN∕AlGaInN LEDs show reduced forward voltage, reduced efficiency droop, and improved light-output power at large currents compared to conventional GaInN∕GaN LEDs.