bluuebunny/crossref_metadata_2025 huggingface dataset:
Inter-satellite Ranging Augmented GPS Relative Navigation for Satellite Formation Flying
Authors: Yang Yang , Li Yong , Rizos Chris , Dempster Andrew G. , Yue Xiaokui
Published: November 2013

An Augmented Relative Navigation System (ARNS) is proposed for autonomous satellite formation flying in low-Earth-orbit (LEO). Inter-satellite ranging systems such as those based on radio frequency transmissions can provide additional observation information, e.g. inter-satellite distance measurement, which can be used to increase the Global Positioning System (GPS) stand-alone observation dimension, or treated as a non-linear equality constraint within a smoothly-constrained Kalman filter. Both approaches are implemented in the proposed ARNS described in this paper. An innovative phase integer ambiguity fixing and feedback scheme is implemented to increase the ambiguity fix rate of the GPS carrier phase measurements. A set of Gravity Recovery and Climate Experiment (GRACE) flight data is used to test and validate the relative navigation performance of the proposed methods. Results indicate that the augmented system can improve relative positioning accuracy by an order of magnitude.
Polygonal ground in the McMurdo Dry Valleys of Antarctica and its relationship to ice-table depth and the recent Antarctic climate history
Authors: Mellon Michael T. , Mckay Christopher P. , Heldmann Jennifer L.
Published: November 2013

The occurrence of dry permafrost overlying ice-rich permafrost is unique to the Antarctic Dry Valleys on Earth and to the high latitudes of Mars. The stability and distribution of this ice are poorly understood and fundamental to understanding the Antarctic climate as far back as a few million years. Polygonal patterned ground is nearly ubiquitous in these regions and is integrally linked to the history of the icy permafrost and climate. We examined the morphology of polygonal ground in Beacon Valley and the Beacon Heights region of the Antarctic Dry Valleys, and show that polygon size is correlated with ice-table depth (the boundary between dry and ice-rich permafrost). A numerical model of seasonal stress in permafrost shows that the ice-table depth is a dominant factor. Remote sensing and field observations of polygon size are therefore important tools for investigating subsurface ice. Polygons are long-lived landforms and observed characteristics indicate no major fluctuations in the ice-table depth during their development. We conclude that the Beacon Valley and Beacon Heights polygons have developed for at least 104years to achieve their present mature-stage morphology and that the ice-table depth has been stable for a similar length of time.
Unusual signals recorded by ocean bottom seismometers in the flooded caldera of Deception Island volcano: volcanic gases or biological activity?
Authors: Bowman Daniel C. , Wilcock William S.D.
Published: November 2013

An ocean bottom seismometer (OBS) network was deployed for 1 month at Deception Island volcano, Antarctica, in early 2005. Although only two volcano-tectonic and three long-period events were observed, the three OBSs located > 2 km apart inside the caldera detected over 3900 events that could not be attributed to known volcanic or hydrothermal sources. These events are found on one instrument at a time and occur in three types. Type 1 events resemble impulsive signals from biological organisms while type 2 and type 3 events resemble long-period seismicity. The largest number of events was observed in a region of volcanic resurgence and hydrothermal venting. All three types occur together suggesting a common cause and they show evidence for a diurnal distribution. The events are most likely to be due to aquatic animals striking the sensors, but a geological source is also possible. In the first case, these signals indicate the presence of a biological community confined to the caldera. In the second case, they imply widespread hydrothermal activity in Port Foster. Future OBS experiments should bury the seismometers, include a hydrophone, deploy instruments side-by-side, or include a video camera to distinguish between biological and geological events.
Identifying childhood characteristics that underlie premorbid risk for substance use disorders: Socialization and boldness
Authors: Hicks Brian M. , Iacono William G. , McGue Matt
Published: November 2013

We utilized a longitudinal twin study (N= 2,510) to identify the child characteristics present prior to initiation of substance use that best predicted later substance use disorders. Two independent traits accounted for the majority of premorbid risk: socialization (conformity to rules and conventional values) and boldness (sociability and social assurance, stress resilience, and thrill seeking). Low socialization was associated with disruptive behavior disorders, parental externalizing disorders, and environmental adversity and exhibited moderate genetic (0.45) and shared environmental influences (0.30). Boldness was highly heritable (0.71) and associated with less internalizing distress and environmental adversity. In combination, these traits exhibited robust associations with adolescent and young adult substance use disorders (R= .48 and .50, respectively) and incremental prediction over disruptive behavior disorders, parental externalizing disorders, and environmental adversity. The results were replicated in an independent sample. Socialization and boldness offer a novel conceptualization of underlying risk for substance use disorders that has the potential to improve prediction and theory with implications for basic research, prevention, and intervention.
The Bank of England, Montagu Norman and the internationalisation of Anglo-Irish monetary relations, 1922–1943
Authors: Drea Eoin
Published: November 2013

The granting of a £7,000m bilateral loan by the British government to the Republic of Ireland in October 2010 highlights the banking co-dependence of modern Anglo-Irish relations. This article provides a Bank-of-England-centred perspective on the development of Irish monetary institutions from the granting of Irish monetary independence in December 1921 to the establishment of the Central Bank of Ireland in 1943. Irrespective of unresolved Anglo-Irish political issues, the Bank of England's Irish policy during this period was based on a strict adherence to Montagu Norman's key central banking principles of co-operation, exclusiveness and political autonomy. This article identifies that the application of these principles survived both the coming to power of Fianna Fáil (Soldiers of Destiny) in Southern Ireland in 1932 and the outbreak of war in 1939. This article also argues that Norman's adherence to a wider internationalist view of monetary relations played an important role in forcing the overwhelmingly Protestant and pro-union Irish commercial banks, headed by the Bank of Ireland, to come to terms with the reality of Irish monetary independence. In this context, Norman's approach to Southern Ireland parallels the transition from Empire to Commonwealth, which began to emerge in the interwar period.
Realization of a 30-W highly efficient and linear reconfigurable dual-band power amplifier using the continuous mode approach
Authors: Carrubba Vincenzo , Maroldt Stephan , Mußer Markus , Walcher Herbert , Van Raay Friedbert , Quay Rüdiger , Ambacher Oliver , Wiegner Dirk , Seyfried Ulrich , Bohn Thomas , Pascht Andreas
Published: November 2013

This paper presents the design methodology and the realization of a highly linear and power-efficient reconfigurable dual-band amplifier based on the continuous/Class-ABJ approach. The Class-ABJ theory allows presenting different reactive solutions on both fundamental and second harmonic terminations compared with the standard Class-AB mode. Despite the various terminations, a constant optimum output performance in terms of power, gain, and efficiency can still be achieved. The output impedances are then translated into frequency thus allowing the realization of broadbandpower amplifiers(PAs) at high-power level of 30 W. In this work, the Class-ABJ broadband approach will be used for the realization of a reconfigurable dual-band power amplifier operating in the two frequency bands 2.1–2.2 and 2.5–2.6 GHz. Continuous wave (CW) measurements on the realized PA show power and efficiency greater than 17 W and 55% in the two frequency bands with peak values up to 30 W and 63.7%. Indeed, it is shown that such novel modes can be predistorted and therefore the linearity requirement can also be met.
Subclinical psychosis syndromes in the general population: results from a large-scale epidemiological survey among residents of the canton of Zurich, Switzerland
Authors: Rössler W. , Ajdacic-Gross V. , Haker H. , Rodgers S. , Müller M. , Hengartner M. P.
Published: November 2013

Aims.

Prevalence and covariates of subclinical psychosis have gained increased interest in the context of early identification and treatment of persons at risk for psychosis.

Methods.

We analysed 9829 adults representative of the general population within the canton of Zurich, Switzerland. Two psychosis syndromes, derived from the SCL-90-R, were applied: ‘schizotypal signs’ and ‘schizophrenia nuclear symptoms’.

Results.

Only a few subjects (13.2%) reported no schizotypal signs. While 33.2% of subjects indicated mild signs, only a small proportion (3.7%) reported severe signs. A very common outcome was no ‘schizophrenia nuclear symptoms’ (70.6%). Although 13.5% of the participants reported mild symptoms, severe nuclear symptoms were very rare (0.5%). Because these two syndromes were only moderately correlated (r = 0.43), we were able to establish sufficiently distinct symptom clusters. Schizotypal signs were more closely connected to distress than was schizophrenia nuclear symptoms, even though their distribution types were similar. Both syndromes were associated with several covariates, such as alcohol and tobacco use, being unmarried, low education level, psychopathological distress and low subjective well-being.

Conclusions.

Subclinical psychosis symptoms are quite frequent in the general population but, for the most part, are not very pronounced. In particular, our data support the notion of a continuous Wald distribution of psychotic symptoms in the general population. Our findings have enabled us to confirm the usefulness of these syndromes as previously assessed in other independent community samples. Both can appropriately be associated with well-known risk factors of schizophrenia.
Glatiramer acetate ameliorates experimental autoimmune neuritis
Authors: Zhang Cun‐Jin , Zhai Hui , Yan Yaping , Hao Junwei , Li Min‐Shu , Jin Wei‐Na , Su Ning , Vollmer Timothy L , Shi Fu‐Dong
Published: November 2013

Glatiramer acetate (GA) is one of the first‐line disease‐modifying medications that have been approved for the treatment of multiple sclerosis via immune modulatory mechanisms. However, it remains unclear whether the immunomodulation effect of GA is central nervous system (CNS) antigen specific. Here, we explored the mechanism of action of GA by subcutaneously injecting GA in experimental autoimmune neuritis (EAN) rats, an animal model for Guillain–Barré syndrome (GBS). Clinical, electrophysiological and histological findings showed that neurological deficits, demyelination and axonal injury of sciatic nerves were all significantly attenuated in Lewis rats when GA was administered before immunization with peripheral nervous system antigen P0. Our results further demonstrated that GA treatment inhibited either P0 or myelin basic protein (MBP) (CNS antigen)‐stimulated auto‐immune T‐cell proliferation in vitro. GA administrated at 10 days after induction of EAN when neurological sign became apparent also ameliorated the severity of disease, inhibited T‐cell response to P0 and MBP and induced shift of proinflammatory and immune modulatory cytokines. Collectively, our findings suggested that GA attenuated neurological deficits in EAN rats and that the immune modulatory mechanisms of GA were not CNS antigen specific.
CO2 phonon mode renormalization using phonon-assisted energy up-conversion
Authors: Tanjeem Nabila , Kawazoe Tadashi , Yatsui Takashi
Published: November 2013

Molecular dissociation under incident light whose energy is lower than the bond dissociation energy has been achieved through multi step excitation using a coupled state of a photon, electron and multimode-coherent phonon as known as the dressed photon phonon (DPP). Here, we have investigated the effects of the DPP on CO2, a very stable molecule with high absorption and dissociation energies, by introducing ZnO nanorods to generate the DPP. Then, the changes in CO2 absorption bands were evaluated using light with a wavelength longer than the absorption wavelength, which confirmed the DPP-assisted energy up-conversion. To evaluate the specific CO2 modes related to this process, we measured the CO2 vibration-rotation spectra in the near-infrared region. Detailed analysis of the 3ν3 vibrational band when a DPP source is present showed that DPP causes a significant increase in the intensity of certain absorption bands, especially those that require higher energies to activate.
Wavelength selection method based on test analysis of variance: application to oximetry
Authors: Li Wei , Lin Ling , Li Gang
Published: November 2013

A novel method that uses ANOVA, which can be put into other spectral analysis is proposed for wavelength selection in oximetry.
In vivo ratiometric Zn2+ imaging in zebrafish larvae using a new visible light excitable fluorescent sensor
Authors: Liu Zhipeng , Zhang Changli , Chen Yuncong , Qian Fang , Bai Yang , He Weijiang , Guo Zijian
Published: November 2013

In vivo ratiometric Zn2+ imaging was realized for the first time in zebrafish larvae using the new visible light excitable sensor constructed via incorporation of the Zn2+ ionphore as the ICT donor of sulfamoylbenzoxadiazole fluorophore.
Photoreleasable thiol chemistry for facile and efficient bioconjugation
Authors: Liu Zhenzhen , Liu Tao , Lin Qiuning , Bao Chunyan , Zhu Linyong
Published: November 2013

Mild and controllable photoreleasable thiol chemistry was utilized for in situ bioconjugation with protein and quantum dot nanoparticles (QDs).
Direct amine-functionalisation of γ-Fe2O3nanoparticles
Authors: Rocher V. , Manerova J. , Kinnear M. , Evans D. J. , Francesconi M. G.
Published: November 2013

Ferrofluids of direct amine-functionalised γ-Fe2O3nanoparticles were preparedviaa novel and simple route. These nanoparticles showed enhanced thermal stability.
Non-symmetric diphosphines based on the imidazole scaffold: an unusual group interchange involving Pd–CH3 and (imidazole)P–Ph cleavage
Authors: Ai Pengfei , Danopoulos Andreas A. , Braunstein Pierre
Published: November 2013

The regioisomeric diphosphines L1 and L2 show dramatic differences in reactivity and when coordinated to the PdCl(Me) fragment, L2 undergoes facile interchange of one PN phenyl with the methyl originating from Pd.
A 1024-sample serum analyzer chip for cancer diagnostics
Authors: Garcia-Cordero Jose L. , Maerkl Sebastian J.
Published: November 2013

A microarray/microfluidic platform measures four protein biomarkers in 1024 blood serum samples for 4096 assays per device with a limit-of-detection of ~1 pM.
Light extraction enhancement with radiation pattern shaping of LEDs by waveguiding nanorods with impedance-matching tips
Authors: Hsiao Yu-Hsuan , Chen Cheng-Ying , Huang Li-Chuan , Lin Guan-Jhong , Lien Der-Hsien , Huang Jian-Jang , He Jr-Hau
Published: November 2013

ZnO nanorods with impedance-matching tips successfully enhance the output of LEDs.
Photovoltaic enhancement due to surface-plasmon assisted visible-light absorption at the inartificial surface of lead zirconate–titanate film
Authors: Zheng Fengang , Zhang Peng , Wang Xiaofeng , Huang Wen , Zhang Jinxing , Shen Mingrong , Dong Wen , Fang Liang , Bai Yongbin , Shen Xiaoqing , Sun Hua , Hao Jianhua
Published: November 2013

A photovoltaic enhancement is due to surface-plasmon assisted visible-light absorption at the inartificial surface of PZT films.
A new highly sensitive and selective fluorescence chemosensor for Cr3+ based on rhodamine B and a 4,13-diaza-18-crown 6-ether conjugate
Authors: Liu Duliang , Pang Tao , Ma Kefeng , Jiang Wei , Bao Xiaofeng
Published: November 2013

A new chemosensor for Cr3+ based on a rhodamine B and 4,13-diaza-18-crown 6-ether conjugate was designed and synthesized.
Insulin-like growth factor II peptide fusion enables uptake and lysosomal delivery of α-N-acetylglucosaminidase to mucopolysaccharidosis type IIIB fibroblasts
Authors: Kan Shih-hsin , Troitskaya Larisa A. , Sinow Carolyn S. , Haitz Karyn , Todd Amanda K. , Di Stefano Ariana , Le Steven Q. , Dickson Patricia I. , Tippin Brigette L.
Published: November 2013

Enzyme replacement therapy for MPS IIIB (mucopolysaccharidosis type IIIB; also known as Sanfilippo B syndrome) has been hindered by inadequate mannose 6 phosphorylation and cellular uptake of rhNAGLU (recombinant human α-N-acetylglucosaminidase). We expressed and characterized a modified rhNAGLU fused to the receptor-binding motif of IGF-II (insulin-like growth factor 2) (rhNAGLU–IGF-II) to enhance its ability to enter cells using the cation-independent mannose 6-phosphate receptor, which is also the receptor for IGF-II (at a different binding site). RhNAGLU–IGF-II was stably expressed in CHO (Chinese-hamster ovary) cells, secreted and purified to apparent homogeneity. The Km and pH optimum of the fusion enzyme was similar to those reported for rhNAGLU. Both intracellular uptake and confocal microscopy suggested that MPS IIIB fibroblasts readily take up the fusion enzyme via receptor-mediated endocytosis that was inhibited significantly (P<0.001) by the monomeric IGF-II peptide. Glycosaminoglycan storage was reduced by 60% (P<0.001) to near background levels in MPS IIIB cells after treatment with rhNAGLU–IGF-II, with half-maximal correction at concentrations of 3–12 pM. A similar cellular uptake mechanism via the IGF-II receptor was also demonstrated in two different brain tumour-derived cell lines. Fusion of rhNAGLU to IGF-II enhanced its cellular uptake while maintaining enzymatic activity, supporting its potential as a therapeutic candidate for treating MPS IIIB.
Approach for quality detection of food by RFID‐based wireless sensor tag
Authors: Nguyen Son Dat , Pham Thong Tien , Fribourg Blanc Eric , Le Ngan Nguyen , Dang Chien Mau , Tedjini Smail
Published: November 2013

A novel wireless sensor for the detection of food quality is presented. The main idea is to transform radio frequency identification (RFID) tags into RFID sensors, owing to a specific design of the tag antenna. From knowledge of the variation of the permittivity of food over time through experimental characterisation, it is possible to detect the time from which the food becomes improper for consumption based on the read‐range measurement of the designed sensing tags. This low‐cost ultra‐high frequency (UHF) RFID passive sensor was designed and experimentally tested on plastic‐film‐wrapped beef meat. The overall agreement between the experimental and simulation results shows the potential of this technique for real‐world applications in food traceability.
Uniquely and arbitrarily shaped laser resonators using 2D InAsP/InP photonic crystals
Authors: Lu T.‐J. , Kim S.‐H. , Postigo P.A. , Regreny P. , Seassal C. , Scherer A.
Published: November 2013

Uniquely and arbitrarily shaped photonic crystal laser cavities were designed, fabricated and characterised. Room temperature lasing emitting at about 1550 nm was observed for all devices when photopumped by an 830 nm wavelength pulse laser with a pulse width of 100 ns. Continuous‐wave lasing was even observed for select devices.
New optimised region‐based multi‐scale image fusion method for thermal and visible images
Authors: Aslantas Veysel , Bendes Emre , Kurban Rifat , Toprak Ahmet Nusret
Published: November 2013

On constructing a fused image by employing only individual pixels or a set of pixels within a small neighbourhood of the images (SIs) acquired from the same scene, pixel‐based fusion techniques suffer from some drawbacks, such as blurring effects, high sensitivity to noise and misregistration. To overcome these drawbacks, this study proposes a new region‐based image fusion method for thermal and visible images. Since different regions with certain properties need to be emphasised differently in the fused image, the corresponding regions of the SIs are optimally merged to obtain the fused image by employing multiple weighting factors (WFs). To improve the quality of the fused images, WFs were optimised by employing the differential evolution algorithm. Furthermore, a new quality metric was also developed to measure the quality of the fused images during the optimisation process. Experimental results show the feasibility of the proposed method.
Visual wafer dies counting using geometrical characteristics
Authors: Xu Shaoqiu , Cheng Zhihang , Gao Yang , Pan Qing
Published: November 2013

This study presents a computer vision‐based wafer dies counting algorithm. It utilises the single model and multi‐model RANSAC (Random Sample Consensus) algorithms to detect the circular contour of a wafer and its dicing lanes, respectively. Statistical analysis is performed to extract the characteristics of layout so that missed dicing lanes can be supplemented. The number of integral dies is counted after segmenting individual dies based on the complete layout information. The experimental results show that the proposed algorithm has high counting accuracy and good computational efficiency.
Effect of intelligent speed adaptation technology on older drivers’ driving performance
Authors: Guo Weihong , Blythe Philip T. , Edwards Simon , Pavkova Katerina , Brennan Dan
Published: November 2013

Excess speeding on roads with a low‐speed limit is a key error in drivers of all ages although the reasons for speeding can be significantly different. Drivers aged over 60 are generally more cautious, and take fewer risks than younger aged drivers. This study investigates whether Intelligent Speed Adaptation (ISA) technology can assist older drivers in maintaining vehicle speed. The technology can be employed in three ways: advisory (AISA), differential (DISA) and mandatory (MISA). Twenty‐six drivers aged over 60 years old participated along with a comparison group of 16 experienced younger drivers aged under 60. All drivers completed four driving tasks in a driving simulator with and without ISA. Results show improvements in speed and lane‐keeping performance vary depending on the type of ISA and driver age and training in effective use of ISA is needed for drivers of all ages. The study is one component of a wider research programme exploring how ITS could potentially help older people overcome some of the difficulties they experience with driving as they age and hopefully help them remain safe drivers for longer, a benefit both to the individual and society.
Traitement des dents ankylosées par corticotomie partielle :
l’Orthodontic Bone Stretching. Étude préliminaire
Authors: Bousquet Philippe , Artz Christèle , Canal Pierre
Published: November 2013

Les dents antérieures ankylosées entraînent une infraclusion et un déficit esthétique
important. Après une revue des techniques utilisées pour replacer ces dents sur l’arcade,
cet article décrit une nouvelle technique permettant de rétablir l’occlusion et
l’esthétique, ou de préparer le cas à un traitement prothétique ou implantaire,
l’Orthodontic Bone Stretching (OBS). Cette technique associe
corticotomie partielle et traitement orthodontique et permet un étirement osseux. Après 8
à 12 semaines d’application des forces, les dents ankylosées sont repositionnées en
occlusion ou, en cas d’extraction, la crête osseuse est à un niveau compatible avec une
réalisation prothétique ou implantaire. La technique d’OBS pourrait être adaptée aux
implants en infraclusion, ou à l’augmentation verticale des crêtes atrophiées.
Traitement de la classe II squelettique au moyen d’un appareil
de Herbst à ancrage osseux
Authors: Luzi Cesare , Luzi Valeriano
Published: November 2013

Les traitements orthodontiques qui ne font pas appel à la coopération des patients
connaissent un engouement croissant depuis plusieurs années. Contrairement aux appareils
amovibles, l’appareil de Herbst ne requière pas la participation des patients. Ce dernier
est largement utilisé comme un appareil fixe fonctionnel, capable de corriger de manière
prédictible les décalages squelettiques de classe II. Les appareils de propulsion qui
s’appuient sur les dents présentent l’inconvénient majeur de provoquer des déplacements
dentaires indésirables, comme la version corono-vestibulaire des incisives mandibulaires.
Ces compensations dento-alvéolaires peuvent, quand elles ne sont pas contrôlées,
compromettre le résultat final. Cet article décrit le traitement efficace de la classe II
squelettique de deux patients, conduit selon un protocole qui associe le port d’un
appareil de Herbst modifié et des mini-vis d’ancrage osseux temporaire (TSADs).
New physics in frustrated magnets: Spin ices, monopoles, etc. (Review Article)
Authors: Zvyagin A. A.
Published: November 2013

During recent years the interest to frustrated magnets has grown considerably. Such systems reveal very peculiar properties which distinguish them from standard paramagnets, magnetically ordered regular systems (like ferro-, ferri-, and antiferromagnets), or spin glasses. In particular great amount of attention has been devoted to the so-called spin ices, in which magnetic frustration together with the large value of the single-ion magnetic anisotropy of a special kind, yield peculiar behavior. One of the most exciting features of spin ices is related to low-energy emergent excitations, which from many viewpoints can be considered as analogies of Dirac's mono-poles. In this article we review the main achievements of theory and experiment in this field of physics.
Vortex pattern and differential conductance in hole underdoped high-temperature superconductors with competing d-wave and antiferromagnetic orders
Authors: Peng Lin , Liu Yongsheng
Published: November 2013

Vortex charges in copper oxide high-temperature superconductors with hole underdoping are investigated by Bogoliubov–de Gennes equations based on a model Hamiltonian with competing antiferromagnetic order and d-wave superconducting order (DSC) with variation of temperature. For the DSC, spin density wave (SDW) and charge density wave (CDW), the transition from stripe to checkerboard pattern and to 2D structure may occur with variation of temperature. Moreover, both spatial profile of the electron density distribution and intensity of the differential conductance are strongly affected by the SDW order around the vortex cores. The transitions from one-dimensional to isotropic two-dimensional structures of the vortex charge and spin-density wave orders may occur by tuning the temperature.
Extended fluid models: Pressure tensor effects and equilibria
Authors: Cerri S. S. , Henri P. , Califano F. , Del Sarto D. , Faganello M. , Pegoraro F.
Published: November 2013

We consider the use of “extended fluid models” as a viable alternative to computationally demanding kinetic simulations in order to manage the global large scale evolution of a collisionless plasma while accounting for the main effects that come into play when spatial micro-scales of the order of the ion inertial scale di and of the thermal ion Larmor radius ϱi are formed. We present an extended two-fluid model that retains finite Larmor radius (FLR) corrections to the ion pressure tensor while electron inertia terms and heat fluxes are neglected. Within this model we calculate analytic FLR plasma equilibria in the presence of a shear flow and elucidate the role of the magnetic field asymmetry. Using a Hybrid Vlasov code, we show that these analytic equilibria offer a significant improvement with respect to conventional magnetohydrodynamic shear-flow equilibria when initializing kinetic simulations.
Depth-resolved confocal micro-Raman spectroscopy for characterizing GaN-based light emitting diode structures
Authors: Chen Wei-Liang , Lee Yu-Yang , Chang Chiao-Yun , Huang Huei-Min , Lu Tien-Chang , Chang Yu-Ming
Published: November 2013

In this work, we demonstrate that depth-resolved confocal micro-Raman spectroscopy can be used to characterize the active layer of GaN-based LEDs. By taking the depth compression effect due to refraction index mismatch into account, the axial profiles of Raman peak intensities from the GaN capping layer toward the sapphire substrate can correctly match the LED structural dimension and allow the identification of unique Raman feature originated from the 0.3 μm thick active layer of the studied LED. The strain variation in different sample depths can also be quantified by measuring the Raman shift of GaN A1(LO) and E2(high) phonon peaks. The capability of identifying the phonon structure of buried LED active layer and depth-resolving the strain distribution of LED structure makes this technique a potential optical and remote tool for in operando investigation of the electronic and structural properties of nitride-based LEDs.
100 s extraction of negative ion beams by using actively temperature-controlled plasma grid
Authors: Kojima A. , Hanada M. , Yoshida M. , Tobari H. , Kashiwagi M. , Umeda N. , Watanabe K. , Grisham L. R.
Published: November 2013

Long pulse beam extraction with a current density of 120 A/m2 for 100 s has been achieved with a newly developed plasma grid (PG) for the JT-60SA negative ion source which is designed to produce high power and long pulse beams with a negative ion current of 130 A/m2 (22 A) and a pulse length of 100 s. The PG temperature is regulated by fluorinated fluids in order to keep the high PG temperature for the cesium-seeded negative ion production. The time constant for temperature controllability of the PG was measured to be below 10 s, which was mainly determined by the heat transfer coefficient of the fluorinated fluid. The measured decay time of the negative ion current extracted from the actively temperature-controlled PG was 430 s which was sufficient for the JT-60SA requirement, and much longer than that by inertial-cooling PG of 60 s. Obtained results of the long pulse capability are utilized to design the full size PG for the JT-60SA negative ion source.
Effect of low-temperature (77 K) quasihydrostatic extrusion on the properties of high-purity titanium: The role of initial structural state
Authors: Tikhonovsky M. A. , Khaimovich P. A. , Kutniy K. V. , Kislyak I. F. , Okovit V. S. , Rudycheva T. Yu.
Published: November 2013

This is a study of the effect of quasihydrostatic extrusion at liquid nitrogen and room temperatures on the evolution of the structure and mechanical properties of high-purity titanium produced by severe plastic deformation in a swaging-extrusion-drawing regime and with subsequent annealing at temperatures of 350–550 °C. It is shown that a combination of severe plastic deformation and cryogenic quasihydrostatic extrusion makes it possible to create high-purity nanocrystalline titanium with high strength and plasticity.
Resonance modes in coplanar lines with integrated Josephson circuits
Authors: Shvetsov A. V. , Satanin A. M. , Mironov V. A. , Il'ichev E.
Published: November 2013

The propagation of microwave radiation in co-planar superconducting lines with Josephson circuits (microresonators) of various configurations is investigated. It is shown that dips in the frequency dependence of the transmission power of the waveguide line modes are associated with local modes of the circuit. The dependencies of shape and position of the dips on an external magnetic field and applied power are found. The calculation results can be used for developing modern cryoelectronic microwave superconducting devices.
Resistivity and magnetocaloric effect in manganites La0.75Ag0.125MnO2.85 and La0.7Ag0.15MnO2.80
Authors: Gamzatov A. G. , Kamilov I. K. , Markelova M. N. , Mukhuchev A. A. , Asvarov A. Sh.
Published: November 2013

We studied structural and thermophysical properties of lanthanum-deficient manganites La0.75Ag0.125MnO2.85 and La0.7Ag0.15MnO2.80. In particular, we report the experimental results on electrical resistance, magnetoresistance, and magnetocaloric effect measured in the temperature range 80 K to 350 K. The magnetocaloric effect is measured using a direct method in a magnetic field of 20 kOe.
Calorimetric study of phase transitions in ocylcyanobiphenyl-barium titanate nanoparticle dispersions
Authors: Sigdel Krishna P. , Iannacchione Germano S.
Published: November 2013

High-resolution ac-calorimetry is reported on the weakly first-order isotropic to nematic (I-N) and the continuous nematic to smectic-A (N-SmA) phase transitions in the liquid crystal octylcyanobiphenyl (8CB) doped with a ferroelectric nanoparticle barium titanate, BaTiO3 (BT). Measurements were performed as a function of BT concentration and over a wide temperature range well above and below the two transitions. From the thermal scans of all samples (having BT mass fraction ϕm = 0.001 to 0.014 and pure 8CB), both the I-N and the N-SmA transitions evolve in character. Specifically, there appears an unusual change of the I-N specific heat peak shape on heating as ϕm increases. Both the transitions shift to lower temperature at a different rate for \documentclass[12pt]{minimal}\begin{document}$\phi _{m} < \phi ^{c}_{m}=0.002$\end{document}ϕm<ϕmc=0.002 as compared to that for \documentclass[12pt]{minimal}\begin{document}$\phi _{m}> \phi ^{c}_{m}$\end{document}ϕm>ϕmc. The effective transition enthalpies are essentially constant and similar to that seen in the bulk. Using a simple geometric model, the mean distance between the BT particles at the cross-over \documentclass[12pt]{minimal}\begin{document}$\phi ^{c}_{m}$\end{document}ϕmc is found to be \documentclass[12pt]{minimal}\begin{document}$\bar{x_{c}}\sim 3\, \mu$\end{document}xc¯∼3μm, which is consistent with an estimated surface extrapolation length b for the nematic director. This suggests that the low ϕm regime is dominated by an impurity/disorder effect while for \documentclass[12pt]{minimal}\begin{document}$\phi _{m} > \phi ^{c}_{m}$\end{document}ϕm>ϕmc the mean distance is small enough for the LC to mediate coupling between the BT ferroelectric nanoparticles.
Experimental performance analysis of a solar evaporative cooler with three different types of pads
Authors: Lotfizadeh H. , Razzaghi H. , Layeghi M.
Published: November 2013

This article presents the operation of a simple DC-powered solar evaporative cooler which was designed in the University of Tehran. This suggested design aims to implement innovation by using the minimum of energy to cool a room and concentrates on solar cooling technology. In the present paper, we describe how it can be useful, without wasting a lot of energy. The cooler was tested in a specified room for measuring different temperatures at different locations in the room and comparing the results in the summer during sequential days in order to evaluate the performance of the cooler. Three kinds of pads are used in the cooler including a conventional pad, a cellulosic pad, and a metal foam pad. The results showed that the performance of the cooler is relatively reasonable during the summer. However, its performance can be more improved using high performance cooling pads such as metal foam pads.
Tuning cationic composition of La:EuTiO3−δ films
Authors: Shkabko Andrey , Xu Chencheng , Meuffels Paul , Gunkel Felix , Dittmann Regina , Weidenkaff Anke , Waser Rainer
Published: November 2013

Eu1−xLaxTiO3−δ (x = 0, 0.3, 0.5) films were deposited in a p(Ar(96%)/H2(4%)) = 4 × 10−4 mbar atmosphere on (LaAlO3)0.3-(Sr2AlTaO6)0.7 vicinal substrates (0.1°). Reflection high-energy electron diffraction oscillation characteristics of a layer-by-layer growth mode were observed for stoichiometric and Ti-rich films and the laser fluence suited to deposit stoichiometric films was identified to be 1.25 J/cm2 independent of the La content. The variety of resulting film compositions follows the general trend of Eu-enrichment for low laser and Ti-enrichment for high laser fluence. X-ray diffraction confirms that all the films are compressively strained with a general trend of an increase of c-axis elongation for non-stoichiometric films. The surfaces of non-stoichiometric films have an increased roughness, the highest sheet resistances, exhibit the presence of islands, and are Eu3+ rich for films deposited at low laser fluence.
Mass and charge transport in 1-alkyl-3-methylimidazolium triflate ionic liquids
Authors: Petrowsky Matt , Burba Christopher M. , Frech Roger
Published: November 2013

Temperature-dependent transport properties in ionic liquids, such as the ionic conductivity and fluidity, are often characterized empirically through equations that require multiple adjustable fitting parameters in order to adequately describe the data. These fitting parameters offer no insight into the molecular-level mechanism of transport. Here the temperature dependence of these transport properties in 1-alkyl-3-methylimidazolium triflate ionic liquids is explained using the compensated Arrhenius formalism (CAF), where the conductivity or fluidity assumes an Arrhenius-like form that also contains a dipole density dependence in the exponential prefactor. The resulting CAF activation energies for conductivity and fluidity are much higher than those obtained from polar organic liquids and electrolytes. The CAF very accurately describes the temperature dependence of both conductivity and fluidity using only system properties (i.e., density and activation energy). These results imply that the transport mechanism in molten salts is very similar to that in polar organic liquids and electrolytes.
Mechanical-plowing-based high-speed patterning on hard material via advanced-control and ultrasonic probe vibration
Authors: Wang Zhihua , Tan Jun , Zou Qingze , Jiang Wei
Published: November 2013

In this paper, we present a high-speed direct pattern fabrication on hard materials (e.g., a tungsten-coated quartz substrate) via mechanical plowing. Compared to other probe-based nanolithography techniques based on chemical- and/or physical-reactions (e.g., the Dip-pen technique), mechanical plowing is meritorious for its low cost, ease of process control, and capability of working with a wide variety of materials beyond conductive and/or soft materials. However, direct patterning on hard material faces two daunting challenges. First, the patterning throughput is ultimately hindered by the “writing” (plowing) speed, which, in turn, is limited by the adverse effects that can be excited/induced during high-speed, and/or large-range plowing, including the vibrational dynamics of the actuation system (the piezoelectric actuator, the cantilever, and the mechanical fixture connecting the cantilever to the actuator), the dynamic cross-axis coupling between different axes of motion, and the hysteresis and the drift effects related to the piezoelectric actuators. Secondly, it is very challenging to directly pattern on ultra-hard materials via plowing. Even with a diamond probe, the line depth of the pattern via continuous plowing on ultra-hard materials such as tungsten, is still rather small (<0.5 nm), particularly when the “writing” speed becomes high. To overcome these two challenges, we propose to utilize a novel iterative learning control technique to achieve precision tracking of the desired pattern during high-speed, large-range plowing, and introduce ultrasonic vibration of the probe in the normal (vertical) direction during the plowing process to enable direct patterning on ultra hard materials. The proposed approach was implemented to directly fabricate patterns on a mask with tungsten coating and quartz substrate. The experimental results demonstrated that a large-size pattern of four grooves (20 μm in length with 300 nm spacing between lines) can be fabricated at a high speed of ∼5 mm/s, with the line width and the line depth at ∼95 nm and 2 nm, respectively. A fine pattern of the word “NANO” is also fabricated at the speed of ∼5 mm/s.
Plasma characteristics of single- and dual-electrode ion source systems utilized in low-energy ion extraction
Authors: Vasquez M. R. , Tokumura S. , Kasuya T. , Wada M.
Published: November 2013

Discharge characteristics in the upstream as well as in the downstream regions of a 50-eV positive ion beam were measured along the beam axis. Single- and dual-electrode configurations made of 0.1-mm diameter tungsten wires were tested. By varying the upstream discharge parameters, the shape of the sheath edge around the extractors, which can either be “planar” or “cylindrical,” can be controlled. The sheath eventually affected the simultaneous extraction of ions and neutralizing electrons. The dual-electrode configuration at the lower discharge current, revealed a homogeneous discharge downstream. At this condition, the edge of the sheath can be inferred to be “planar” which allowed the uniform extraction and propagation of low-energy ions at longer distances. The dual-electrode configuration was capable of transmitting low-energy ions up to 70 mm downstream.
Low-energy positron scattering from gas-phase tetrahydrofuran: A quantum treatment of the dynamics and a comparison with experiments
Authors: Franz J. , Gianturco F. A.
Published: November 2013

In this paper we report new quantum calculations of the dynamics for low-energy positrons interacting with gaseous molecules of tetrahydrofuran. The new quantum scattering cross sections are differential and integral cross sections at collision energies between 1.0 and 25.0 eV and include a careful treatment of the additional effects on the scattering process brought about by the permanent dipole moment of the target molecule. The present results are compared with an extensive range of measured data, both for the angular distributions and for the elastic integral cross sections and agree remarkably well with all findings. The new calculated quantities reported here also show the importance of correcting the experimental integral cross sections for the angular discrimination in the forward direction.
Atomistic force field for alumina fit to density functional theory
Authors: Sarsam Joanne , Finnis Michael W. , Tangney Paul
Published: November 2013

We present a force field for bulk alumina (Al2O3), which has been parametrized by fitting the energies, forces, and stresses of a large database of reference configurations to those calculated with density functional theory (DFT). We use a functional form that is simpler and computationally more efficient than some existing models of alumina parametrized by a similar technique. Nevertheless, we demonstrate an accuracy of our potential that is comparable to those existing models and to DFT. We present calculations of crystal structures and energies, elastic constants, phonon spectra, thermal expansion, and point defect formation energies.
Current injection induced terahertz emission from 4H-SiC p-n junctions
Authors: Andrianov A. V. , Gupta J. P. , Kolodzey J. , Sankin V. I. , Zakhar'in A. O. , Vasilyev Yu. B.
Published: November 2013

We report on current injection induced terahertz electroluminescence from 4H-SiC p-n junctions with operating temperature up to 270 K. The emission is assigned to intracenter optical transitions in donor centers, initiated by the injection of non-equilibrium carriers into the n-doped region of a SiC p-n junction. At a pumping current of 300 mA at 100 K, the integrated output power was 58 μW from the device surface with an area of 3 mm2. These results suggest that THz emitting devices can be fabricated with simple structures of SiC p-n junctions, with relatively high operating temperatures and reasonable output powers.
Strain-induced orbital polarization and multiple phase transitions in Ba2MnWO6 from first principles
Authors: Ju Weiwei , Zhao Bao , Yang Zhongqin
Published: November 2013

Electronic structures of double perovskite Ba2MnWO6 with epitaxial strain are explored by using methods based on density functional theory. An in-plane compressive strain is found not only resulting in a semiconductor-metal transition (SMT), but also altering the magnetic structures, from different kinds of antiferromagnetic to ferromagnetic orders. Orbital polarization and different orbital occupancies of Mn \documentclass[12pt]{minimal}\begin{document}$d_{z^{2}}$\end{document}dz2 and \documentclass[12pt]{minimal}\begin{document}$d_{x^{2}-y^{2}}$\end{document}dx2−y2 states, induced by the epitaxial strain, are employed to understand the SMT. The rich magnetic phase transitions are rationalized by a magnetic stabilization mechanism. Our results show that many technological applications may be carried out in the material with the control of epitaxial strain.
Experimental evaluation of anti-sound approach in damping self-sustained thermoacoustics oscillations
Authors: Li Xinyan , Zhao Dan , Li Junwei , Xu Yousheng
Published: November 2013

Self-sustained thermoacoustics oscillations most often arise due to the coupling between unsteady heat release and acoustic waves. The large-amplitude oscillations are wanted in thermoacoustic engine systems. However, they are undesirable in many other systems such as aero-engine afterburners, rocket motors, ramjets, and gas turbines, since the oscillations may become so intense that they cause structural damage and costly mission failure. In this work, we experimentally investigate the “anti-sound” approach in damping Rijke-type thermoacoustic oscillations by actuating a monopole-like sound source. For this, four different least-mean-square (LMS) algorithms are used to determine the “anti-sound” signal to drive the actuator. Comparison is then made. It is found that the LMS-based “anti-sound” approach is able to minimize the thermoacoustic oscillations, even when the operating conditions are slightly changed. Sound pressure level is reduced by 45 dB. Finally, a numerical model is developed to gain insights on the interaction between the monopole sound source and the system. Unsteady heat release from the flame is assumed to be caused by its surface variations resulting from the oncoming acoustic fluctuations. By linearizing the flame model and recasting it into the classical time-lag N−τ formulation, the thermoacoustic system transfer function is calculated. Compared with the experimental measurement by injecting a broad-band white noise, good agreement is obtained.
Quantum interference and control of the optical response in quantum dot molecules
Authors: Borges H. S. , Sanz L. , Villas-Boas J. M. , Alcalde A. M.
Published: November 2013

We discuss the optical response of a quantum molecule under the action of two lasers fields. Using a realistic model and parameters, we map the physical conditions to find three different phenomena reported in the literature: the tunneling induced transparency, the formation of Autler-Townes doublets, and the creation of a Mollow-like triplet. We found that the electron tunneling between quantum dots is responsible for the different optical regime. Our results not only explain the experimental results in the literature but also give insights for future experiments and applications in optics using quantum dots molecules.
Ordering-enhanced dislocation glide in III-V alloys
Authors: McMahon William E. , Kang Joongoo , France Ryan M. , Norman Andrew G. , Friedman Daniel J. , Wei Su-Huai
Published: November 2013

Ordering-induced effects on dislocations in metallic alloys have been extensively studied due to their importance in technology applications. We demonstrate that dislocation behavior in ordered III-V semiconductor alloys can be drastically different. This is because ordering in bulk metallic alloys is generally stable, whereas the surface-stabilized group-III sublattice ordering of a III-V alloy is only metastable in the bulk. Here, we show that dislocation glide can release some of the energy stored by ordering of III-V alloys, enhancing the glide of any dislocation which cuts through the ordered layers to create an antiphase boundary in the ordering pattern. This leads to an experimentally observed glide-plane switch which is unique to ordered III-V alloys. Implications for other unique strain-relaxation processes in III-V ordered alloys are also discussed.