bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling the Structure of the Windy Torus in Quasars
Authors: Gallagher Sarah C. , Abado Mathew M. , Everett John E.
Published: July 2014

Mass ejection in the form of winds or jets appears to be as fundamental to quasar activity as accretion. A convincing argument for radiation pressure driving this ionized outflow can be made within the dust sublimation radius. Beyond, radiation pressure is even more ubiquitous, as high energy photons from the central engine can now push on dust grains. This physics underlies the dusty-wind model for the putative obscuring torus. Specifically, the dusty wind in our model is first launched from the outer accretion disk as a magneto-centrifugal wind and then accelerated and shaped by radiation pressure from the central continuum. Such a wind can plausibly account for both the necessary obscuring medium to explain the observed ratio of broad-to-narrow-line quasars and the mid-infrared emission commonly seen in quasar spectral energy distributions.
Close pairs of galaxies with different activity levels
Authors: Nazaryan T. A. , Petrosian A. R. , Hakobyan A. A. , McLean B. J. , Kunth D.
Published: July 2014

We selected and studied 180 pairs with d V < 800 km s−1 and Dp < 60 kpc containing Markarian (MRK) galaxies to investigate the dependence of galaxies integral parameters, star-formation (SF) and active galactic nuclei (AGN) properties on kinematics of pairs, their structure and large-scale environments. Projected radial separation Dp and perturbation level P are better measures of interaction strength than dV. The latter correlates with the density of large-scale environment and with the morphologies of galaxies. Both galaxies in a pair are of the same nature, the only difference is that MRK galaxies are usually brighter than their neighbors. Specific star formation rates (SSFR) of galaxies in pairs with smaller Dp or d V is in average 0.5 dex higher than that of galaxies in pairs with larger Dp or d V. Closeness of a neighbor with the same and later morphological type increases the SSFR, while earlier-type neighbors do not increase SSFR. Major interactions/mergers trigger SF and AGN more effectively than minor ones. The fraction of AGNs is higher in more perturbed pairs and pairs with smaller Dp. AGNs typically are in stronger interacting systems than star-forming and passive galaxies. There are correlations of both SSFRs and spectral properties of nuclei between pair members.
Host galaxy properties of radio selected AGN
Authors: Bonzini M. , Mainieri V. , Padovani P. , Kellermann K. I. , Miller N. , Rosati P. , Tozzi P. , Vattakunnel S.
Published: July 2014

With the goal of investigating the link between black hole (BH) and star formation (SF) activity, we study a deep sample of radio selected star forming galaxies (SFGs) and active galactic nuclei (AGNs). Using a multi-wavelength approach we characterize their host galaxies properties (stellar masses, optical colors, and morphology). Moreover, comparing the star formation rate derived from the radio and far-infrared luminosity, we found evidences that the main contribution to the radio emission in the radio-quiet AGNs is star-formation activity in their host galaxy.
The starburst – active galactic nuclei connection on nuclear scales in near by Seyfert galaxies
Authors: Esquej Pilar
Published: July 2014

Several works have shown that there is an empirical correlation between the star formation rate and the luminosity of the active galactic nucleus (and thus the black hole accretion rate, ṀBH) of Seyfert galaxies. This suggests a physical relation between the gas forming stars on kpc scales and the gas on sub-pc scales that is feeding the black hole. Simulations predict this relation and also that the correlation should be more prominent on smaller physical scales. We have compiled high angular resolution (0.4–0.8″) mid-infrared spectroscopy obtained with T-ReCS, VISIR, and Michelle of 29 Seyferts. We use the 11.3 μm PAH feature to probe the star formation activity in the inner ~65 pc, and its relation with the ṀBH on these physical scales.
Multiwavelength Study of Radio Loud Early-Type Galaxies from the B2 Sample
Authors: Sahu Sheetal Kumar , Chaware Laxmikant , Pandey S. K. , Kulkarni Samridhi , Pandge M. B. , Chakradhari N. K.
Published: July 2014

We present multiwavelength study of a sample of radio loud early-type galaxies chosen from the B2 sample. We performed surface photometry in BVR broad band filters and Hα narrow band filter on CCD images of sample galaxies using IGO 2m telescope, Pune (INDIA), to get radial profiles of various photometric and geometrical parameters that describe elliptical isophotes fitted to the 2D light distribution of the galaxies. The analysis of radial profiles of quantities such as the (local) surface brightness, the ellipticity, and the deviations from elliptical isophotes parametrized by the Fourier coefficients are main focus of our study. We generated color maps, residual maps, and dust extinction maps, Hα emission maps of the galaxies to study the morphology of the dust and ionized gas content present in the galaxies. We carried out detailed analysis of the properties of the dust present in our sample galaxies. Additionaly, we investigated properties of the dust in the central ~10 arcsec region of our sample galaxies using optical images available from the HST (WFPC2) data archive. We estimated mass and temperature of the dust, molecular gas mass, in the sample galaxies using FIR fluxes of the galaxies obtained from IRAS.

We used spectroscopic data available from the SDSS (DR7) to get an estimate of the mass of the central super massive black-hole for B2 1257+28 (NGC 4874). We plotted rotation curve for coma cluster (Abell 1656), which indicates the presence of dark matter halo around the galaxy B2 1257+28.
The Circumgalactic Medium of Quasars
Authors: Hennawi Joe
Published: July 2014

I will argue that observations of the diffuse gas in the outskirts of quasar host galaxies, or the so called circumgalactic medium, are essential for understanding how luminous quasars evolve in a cosmological context. Such observations also provide a fruitful comparison to theory, because hydrodynamics at moderate overdensities is much easier to simulate than the complicated processes which trigger quasar activity. A novel technique will be introduced, whereby a foreground quasar can be studied in absorption against a background quasar, resolving scales as small as 30 kpc. This experiment reveals a rich absorption spectrum which contains a wealth of information about the physical conditions of diffuse gas around quasars. Hydrodynamical simulations of the massive dark matter halos which host luminous quasars under predict the amount of cool gas observed in quasar environs by a large factor, challenging our understanding of how massive galaxies form. I will also discuss a very sensitive search for Ly-alpha emission from the same gas which we study in absorption.
Compact nuclear objects and properties of their parent galaxies
Authors: Zasov Anatoly V. , Cherepashchuk Anatoly M.
Published: July 2014

We consider the relationship between the masses of the compact nuclear objects in the centers of disky galaxies – supermassive black holes (SMBHs) or nuclear star clusters (NCs) – and such parameters as the maximal velocity of rotation Vmax, obtained from the rotation curves, indicative dynamical mass M25, and the color index (B−V) of their parent galaxies. It was found that the mass of nuclear clusters Mnc correlates more closely with the velocity of rotation and total mass of galaxies than the mass of supermassive black holes Mbh. The dependence of masses of the central objects on the color index is bimodal: galaxies of the red group (red-sequence), which have (B−V) > 0.6−0.7, differ from bluer galaxies, by higher values of Mbh for similar host-galaxy parameters. In contrast, in the diagrams for nuclear clusters the “blue” and “red” galaxies form unified sequences. It agrees with scenarios in which most red-group galaxies form as a result of loss of interstellar gas in a stage of high nuclear activity in galaxies whose central black-hole masses are high, exceeding 106 − 107M⊙ (depending on the total mass of the galaxy). The active growth of nuclear star clusters possibly begun after the violent AGN activity.
Using AGN Variability Surveys to explore the AGN-Galaxy Connection
Authors: Sarajedini Vicki L.
Published: July 2014

Variability is a successful technique used to identify active galactic nuclei in both ground and space-based galaxy surveys. Optical variability surveys using HST have uncovered a number of AGN in deep extragalactic fields extending to z ~ 3 and probing intrinsically faint sources. Mid-IR variability surveys using Spitzer have identified a significant number of AGN and are particularly sensitive to obscured sources. Many variability-detected AGN are not strong X-ray sources or lack the characteristic colors of AGN and would thus be unidentified using other selection techniques. In this conference proceedings, I discuss the nature of the variable sources and their host galaxies identified in deep extragalactic optical and mid-IR surveys.
High redshift quasars monitoring campaign
Authors: Botti Ismael , Lira Paulina , Martinez Jorge , Netzer Hagai , Kaspi Shai
Published: July 2014

We present an update of the monitoring campaign we have undertaken to probe the most massive black holes in powerful quasars at high redshift through the reverberation mapping technique. Once this campaign has finished, we will be able to directly measure broad line region (BLR) sizes of quasars at z ~ 2−3, improving dramatically the BLR size-luminosity relation, and therefore, black hole mass estimates based on this relationship. So far, we have identified a dozen highly variable sources suitable for future cross-correlation analysis and reverberation measurements.
Large-scale structure studies with AGN in the eROSITA/SRG All-Sky Survey
Authors: Kolodzig Alexander , Gilfanov Marat , Hütsi Gert , Sunyaev Rashid
Published: July 2014

The four-year X-ray all-sky survey (eRASS) of the eROSITA telescope aboard the Spektrum-Roentgen-Gamma satellite will detect ~ 3 million active galactic nuclei (AGN) with a median redshift of z≈1. We show that this unprecedented AGN sample, complemented with redshift information, will supply us with outstanding opportunities for large-scale structure research. For the first time with a sample of X-ray selected AGN, it will become possible to perform detailed redshift- and luminosity-resolved studies of the linear bias factor, and to convincingly detected baryonic acoustic oscillations (BAOs). To exploit the full potential of the eRASS AGN sample, photometric and spectroscopic surveys of large areas and a sufficient depth will be needed.
Conference Summary
Authors: Sanders David B.
Published: July 2014

This conference on “Multi-wavelength AGN Surveys and Studies” has provided a detailed look at the explosive growth over the past decade, of available astronomical data from a growing list of large scale sky surveys, from radio-to-gamma rays. We are entering an era were multi-epoch (months to weeks) surveys of the entire sky, and near-instantaneous follow-up observations of variable sources, are elevating time-domain astronomy to where it is becoming a major contributor to our understanding of Active Galactic Nuclei (AGN). While we can marvel at the range of extragalactic phenomena dispayed by sources discovered in the original “Markarian Survey” – the first large-scale objective prism survey of the Northern Sky carried out at the Byurakan Astronomical Observtory almost a half-century ago – it is clear from the talks and posters presented at this meeting that the data to be be obtained over the next decade will be needed if we are to finally understand which phase of galaxy evolution each Markarian Galaxy represents.
60 years of IAU symposia
Authors: Mickaelian Areg M.
Published: July 2014

The history of the International Astronomical Union (IAU) meetings goes back to 1922 when the IAU I General Assembly (GA) was held in Rome, Italy, following the IAU creation in 1919. However, until 1953, no individual symposia were organized and GA was the only official gathering for astronomers. Altogether, 8 IAU GA were held during 1922–1952.
Analysis of Au metal–metal contacts in a lateral actuated RF MEMS switch
Authors: Gaitzsch Markus , Kurth Steffen , Voigt Sven , Haas Sven , Gessner Thomas
Published: July 2014

This paper reports on the ohmic contacts of an radio-frequency micro-electro-mechanical-system (RF MEMS) switch. The structure of the MEMS is described briefly to give information about the organization of the switch device. The most significant performance data are reported, indicating very low actuation voltage below 5 V, switching time of <10 µs and good RF performance for frequencies up to 5 GHz. Since the contact performance is a key for excellent RF performance in the actuated state and for high reliability as well the article is focused on the contacts. It is supposed that asperities are building the current path in a closed contact, which is proved by measurements of the closing process with high time resolution. The measurements exhibit very good power-handling capabilities of the contacts. The reported findings render prior theoretical experiments with a physical device.
Psychometric Properties of a Revised Version of the Ten Item Personality Inventory
Authors: Chiorri Carlo , Bracco Fabrizio , Piccinno Tommaso , Modafferi Cinzia , Battini Valeria
Published: July 2014

Gosling, Rentfrow, and Swann (2003) developed the Ten-Item Personality Inventory (TIPI) to meet the need of very short measures of the Big Five for time-limited contexts or large survey questionnaires. In this paper we show the inadequacy of the Italian version downloadable from Gosling’s website and we report the results of four studies in which the psychometric properties of a revised version (I-TIPI-R) were investigated in student and general population samples. This new version showed adequate factor structure, test-retest reliability, self-observer agreement and convergent and discriminant validity with the Big Five Inventory (BFI). Moreover, I-TIPI-R and BFI scores did not differ in their correlations with measures of affect, self-esteem, optimism, emotion regulation, and social desirability. Overall, the results suggest that the I-TIPI-R can be considered a valid and reliable alternative to the BFI for the assessment of basic personality traits when very short measures are needed.
Is This Testimony Truthful, Fabricated, or Based on False Memory?
Authors: Volbert Renate , Steller Max
Published: July 2014

In 1989, Steller and Köhnken presented a systematic compilation of content characteristics for distinguishing between truthful and fabricated testimonies (criteria-based content analysis – CBCA) designed to be applied within a more comprehensive overall diagnostic procedure known as statement validity assessment (SVA; Steller, 1989 ). The subsequent 25 years have seen a marked increase in knowledge about the distinction between experience-based and non-experience-based statements. This supports the SVA approach and permits a better explanation of the underlying processes. The rationale of CBCA is that a true statement differs in content quality from a fabricated account because (a) a truth teller can draw on an episodic autobiographical representation containing a multitude of details, whereas a liar has to relate to scripts containing only general details of an event; and (b) a liar is busier with strategic self-presentation than a truth teller. The present article proposes a modified model of content characteristics that pays greater attention than before to these underlying processes. SVA takes into account that content quality is influenced not only by the veracity of a statement but also by other (personal and contextual) variables that need to be considered in the individual credibility assessment. Theoretical analyses and empirical research do not indicate comparable qualitative differences between true statements and those based on false memories. Witnesses giving testimony based on false memories do not fabricate false statements actively, and they make no effort to conceal a deception; they are not deceiving but mistaken. In these cases, a noncritical application of content criteria can lead to false results. To examine the hypothesis that a statement is based on a false memory, it is necessary to focus on the way in which the statement has emerged and evolved.
Association between serum free fatty acid levels and nonalcoholic fatty liver disease: a cross-sectional study
Authors: Zhang Juanwen , Zhao Ying , Xu Chengfu , Hong Yani , Lu Huanle , Wu Jianping , Chen Yu
Published: July 2014

High serum free fatty acid (FFA) levels are associated with metabolic syndrome (MS). This study aimed to assess the association of fasting serum FFAs with nonalcoholic fatty liver disease (NAFLD) in a Chinese population. A total of 840 subjects fulfilled the diagnostic criteria of NAFLD and 331 healthy control participants were enrolled in this cross-sectional study. Fasting serum FFA levels and other clinical and laboratory parameters were measured. NAFLD patients had significantly higher serum FFA levels than controls (P < 0.001). Serum FFA levels were significantly and positively correlated with parameters of MS, inflammation indexes and markers of hepatocellular damage. Elevated serum FFA levels were found in NAFLD subjects with individual components of MS (obesity, hypertriglyceridaemia and hyperglycaemia). Stepwise regression showed that serum FFA levels were an independent factor predicting advanced fibrosis (FIB-4 ≥ 1.3) in NAFLD patients. Serum FFA levels correlated with NAFLD and could be used as an indicator for predicting advanced fibrosis in NAFLD patients.
Nanosecond Pulsed Electric Fields (nsPEFs) Regulate Phenotypes of Chondrocytes through Wnt/β-catenin Signaling Pathway
Authors: Zhang Kun , Guo Jinsong , Ge Zigang , Zhang Jue
Published: July 2014

Nanosecond pulsed electric fields (nsPEFs) characterized by high voltage, low energy and non-thermal effects, have been broadly investigated as a potential tumor therapy; however, little is known about their effects on somatic cells. In this current study, we evaluated effects of nsPEFs on the phenotype of chondrocytes (morphology, glycosaminoglycan (GAG) content, proliferation and gene expression) and explored the mechanisms involved. Our results demonstrated that exposing chondrocytes to nsPEFs led to enhanced proliferation and dedifferentiation, evidenced by the upregulated gene expression of collagen type I (COL I) and downregulated gene expression of Sox9, collagen type II (COL II) and aggrecan (AGG) with activation of the wnt/β-catenin signaling pathway. Inhibition of the wnt/β-catenin pathway partially blocked these effects. Thus we concluded that nsPEFs induce dedifferentiation of chondrocytes partially through transient activation of the wnt/β-catenin signaling pathway.
In-line microfluidic integration of photonic crystal fibres as a highly sensitive refractometer
Authors: Wu Chuang , Tse Ming-Leung Vincent , Liu Zhengyong , Guan Bai-Ou , Zhang A. Ping , Lu Chao , Tam Hwa-Yaw
Published: July 2014

Photonic crystal fibres appear to be an ideal platform for the realisation of novel optofluidic devices and sensors due to their waveguide nature and microstructured architecture.
Design of novel chiral N,N,O-tridentate phenanthroline ligands and their application to enantioselective addition of organozinc reagents to aldehydes
Authors: Naganawa Yuki , Namba Tomoya , Aoyama Tomotaka , Shoji Kentaro , Nishiyama Hisao
Published: July 2014

The novel chiral N,N,O-tridentate ligands (BinThro) containing binaphthyl and phenanthroline units were developed. The enantioselective organozinc addition to aldehydes was performed in the presence of BinThro (S)-1 with up to 95% ee.
Improvement of the water solubility of tolfenamic acid by new multiple-component crystals produced by mechanochemical methods
Authors: Gaglioti K. , Chierotti M. R. , Grifasi F. , Gobetto R. , Griesser U. J. , Hasa D. , Voinovich D.
Published: July 2014

Tolfenamic acid (HTA) is a drug characterized by very poor solubility in water. By mechanochemical methods, new solid-state forms of HTA were obtained, showing better thermal stability than pure HTA and an improved dissolution rate.
Quantum rules for planar boron nanoclusters
Authors: Arvanitidis Athanasios G. , Tai Truong Ba , Nguyen Minh Tho , Ceulemans Arnout
Published: July 2014

The nodal structure of boron sheets follows the pattern of cylindrical bessel function.
The effects of electronic coupling between capping molecules and quantum dots on the light absorption and emission of octyl, styryl, and 4-ethynylstyryl terminated silicon quantum dots
Authors: Le Thu-Huong , Jeong Hyun-Dam
Published: July 2014

Optical properties of silicon quantum dots (Si QDs) are greatly influenced by their size and surface chemistry.
Halogen bonding interaction of chloromethane with several nitrogen donating molecules: addressing the nature of the chlorine surface σ-hole
Authors: Varadwaj Pradeep R. , Varadwaj Arpita , Jin Bih-Yaw
Published: July 2014

The small and positive σ-hole on the outermost extension of the C–Cl covalent bond in CH3Cl can adequately form halogen bonded interactions with the RN series of thirteen other molecules, R = FC, ClC, BrC, CH3C, HOC, HSC, PCC, P, CCl3C, SiH3C, NCC, CNC, and NaC.
Bacterial symbionts enhance photo-fermentative hydrogen evolution of Chlamydomonas algae
Authors: Lakatos Gergely , Deák Zsuzsanna , Vass Imre , Rétfalvi Tamás , Rozgonyi Szabolcs , Rákhely Gábor , Ördög Vince , Kondorosi Éva , Maróti Gergely
Published: July 2014

The association of photosynthesizingChlamydomonasalgae and actively respiring bacterial partners represents an alternative, efficient and sustainable approach for biohydrogen generation.
Application of a differential technique in inductively coupled plasma emission spectrometry: presentation of a relative reference measurement procedure for the determination of total mass fraction of uranium in mineralised rocks and similar matrices
Authors: Murugesan P. , Khorge C. R. , Patwardhan A. A. , Kumar Manjeet , Tarafder P. K. , Rathore D. P. S.
Published: July 2014

A differential inductively coupled plasma emission spectrometry as a relative reference measurement procedure for the determination of total mass fraction of uranium in mineralized rocks, ores and similar matrices is presented.
Three-dimensional flash flow microreactor for scale-up production of monodisperse PEG–PLGA nanoparticles
Authors: Min Kyoung-Ik , Im Do Jin , Lee Hyune-Jea , Kim Dong-Pyo
Published: July 2014

We present a pressure-tolerant 3D parallel polyimide (PI) film microreactor operating at up to ~160 bars with direct 3D flow focusing geometry for mass production of PEG–PLGA nanoparticles in a ~101 gram-scale (g h−1).
A microfluidic linear node array for the study of protein–ligand interactions
Authors: Li Cheuk-Wing , Yu Guodong , Jiang Jingyun , Lee Simon Ming-Yuen , Yi Changqing , Yue Wanqing , Yang Mengsu
Published: July 2014

Through utilizing streamline reversibility, we developed a microfluidic device for the continuous separation of free ligands from a protein–ligand complex for off-chip detection.
Fast synthesis of high-quality reduced graphene oxide at room temperature under light exposure
Authors: Some Surajit , Kim Sungjin , Samanta Khokan , Kim Youngmin , Yoon Yeoheung , Park Younghun , Lee Sae Mi , Lee Keunsik , Lee Hyoyoung
Published: July 2014

New reducing agents, such as sodium–benzophenone solutions and light can generate solvated radical anions and electrons that can produce high-quality rGO or convert to a higher degree of reduced N-doped rGO with hydrazine solutions at room temperature.
Probing molecular pathways for DNA orientational trapping, unzipping and translocation in nanopores by using a tunable overhang sensor
Authors: Wang Yong , Tian Kai , Hunter Lehr L. , Ritzo Brandon , Gu Li-Qun
Published: July 2014

Nanopores provide a unique single-molecule platform for genetic and epigenetic detection.
New insights into micro/nanoscale combined probes (nanoAuger, μXPS) to characterize Ag/Au@SiO2core–shell assemblies
Authors: Ledeuil J. B. , Uhart A. , Soulé S. , Allouche J. , Dupin J. C. , Martinez H.
Published: July 2014

This work has examined the elemental distribution and local morphology at the nanoscale of core@shell Ag/Au@SiO2particles.
Study of exciton transfer in dense quantum dot nanocomposites
Authors: Guzelturk Burak , Hernandez-Martinez Pedro Ludwig , Sharma Vijay Kumar , Coskun Yasemin , Ibrahimova Vusala , Tuncel Donus , Govorov Alexander O. , Sun Xiao Wei , Xiong Qihua , Demir Hilmi Volkan
Published: July 2014

Direct or diffusion assisted exciton transfer in varying density colloidal quantum dot incorporated hybrid conjugated polymer nanocomposites.
Alkylene-bridged viologen dendrimers: versatile cell delivery tools with biosensing properties
Authors: Bongard Dirk , Bohr Wilhelm , Swierczek Marta , Degefa Tesfaye Hailu , Walder Lorenz , Brandt Roland
Published: July 2014

Two types of tailored viologen dendrimers with different spacer lengths between the viologen (4,4′-bipyridinium) units have been prepared. The condensation of dsDNA induced by the dendrimers was monitored with a new electrochemical technique. This allowed us to optimize the transfection media for high dendriplex concentration.
Highly efficient and stereocontrolled oxidative coupling of tetrahydropyrroloindoles: synthesis of chimonanthines, (+)-WIN 64821 and (+)-WIN 64745
Authors: Sun Deqian , Xing Changyu , Wang Xiaoqing , Su Zhongquan , Li Chaozhong
Published: July 2014

The I2-mediated oxidative dimerization of tetrahydropyrroloindoles allows the convenient and efficient synthesis of target molecules.
Dual effects of mesoscopic fillers on the polyethersulfone modified cyanate ester: enhanced viscoelastic effect and mechanical properties
Authors: Hu Zhongnan , Zhang Jie , Wang Huiping , Li Tian , Liu Zhuoyu , Yu Yingfeng
Published: July 2014

Enlarging the filler content and decreasing the filler size contribute to enhancing both viscoelastic effect and mechanical property of polyethersulfone modified cyanate system.
Evolution of cellulose into flexible conductive green electronics: a smart strategy to fabricate sustainable electrodes for supercapacitors
Authors: Liu Shilin , Yu Tengfei , Wu Yuehan , Li Wei , Li Bin
Published: July 2014

The integration of cellulose with electronic elements could form green electronics with the merits of the biopolymer and conductive polymer.
Base catalytic activity of alkaline earth MOFs: a (micro)spectroscopic study of active site formation by the controlled transformation of structural anions
Authors: Valvekens P. , Jonckheere D. , De Baerdemaeker T. , Kubarev A. V. , Vandichel M. , Hemelsoet K. , Waroquier M. , Van Speybroeck V. , Smolders E. , Depla D. , Roeffaers M. B. J. , De Vos D.
Published: July 2014

The selective decomposition of structural nitrate anions in alkaline earth MOFs generates highly dispersed base sites with catalytic applications.
Sub-10 nm BaLaF5:Mn/Yb/Er nanoprobes for dual-modal synergistic in vivo upconversion luminescence and X-ray bioimaging
Authors: Rao Ling , Lu Wei , Zeng Tianmei , Yi Zhigao , Wang Haibo , Liu Hongrong , Zeng Songjun
Published: July 2014

Sub-10 nm ultra-small BaLaF5:Mn/Yb/Er nanoparticles were synthesized by a simple solvothermal method forin vivoupconversion luminescence and X-ray bioimaging.
Superior characteristics of graphene field effect transistor enclosed by chemical-vapor-deposition-grown hexagonal boron nitride
Authors: Iqbal Muhammad Waqas , Iqbal Muhammad Zahir , Jin Xiaozhan , Eom Jonghwa , Hwang Chanyong
Published: July 2014

We report the characterization of high-quality chemical-vapor-deposition (CVD)-grown graphene devices on CVD-grown hexagonal boron nitride (h-BN).
Compact six‐band triplexer using stub‐loaded stepped impedance resonators
Authors: Zhang Ling‐Zhi , Wu Bian , Qiu Feng
Published: July 2014

A novel six‐band triplexer based on short‐ and open‐ended stub‐loaded stepped impedance resonators (SLSIRs) is presented. The stub added at the centre of the SIR introduces a flexible even mode close to the first odd mode, realising a dual‐band response with nearby passbands and a wide stop band. Three second‐order dual‐band channels combined with a common T‐shaped SIR feed line form a six‐band triplexer with compact size, low insertion loss and high isolation. A practical six‐band triplexer operating at 1.9/2.4, 3.5/4.2 and 5.2/5.8 GHz is designed and realised based on the proposed multi‐band multiplexer coupling scheme.
14–30 GHz low‐power sub‐harmonic single‐balanced gate‐pumped mixer with transformer combiner in 0.18 μm CMOS
Authors: Chiou H.‐K. , Kuo S.‐C. , Chung H.‐Y.
Published: July 2014

A 14–30 GHz sub‐harmonic single‐balanced gate‐pumped mixer with a wideband transformer combiner in 0.18 μm CMOS technology is presented. The transistors of the sub‐harmonic mixer core are biased at weak inversion to lower the required local oscillator (LO) driving power and DC power consumption. The wideband combiner including a Marchand balun and a 1:1:1 trifilar transformer was designed to combine the radio frequency (RF) and LO driving signals to produce four states of signals, where the RF frequency is about twice the LO frequency. Two quarter‐wavelength transmission lines are adopted to improve the RF‐to‐intermediate‐frequency (IF) and 2LO‐to‐IF isolations. The measured results show that the maximum conversion gain of −1 dB is at 18 GHz and a 3 dB bandwidth is from 14 to 30 GHz while applying the LO driving power of only 1 dBm. The total power consumption including the output buffer is only 7.8 mW.
Full‐duplex MIMO system based on antenna cancellation technique
Authors: Foroozanfard E. , Franek O. , Tatomirescu A. , Tsakalaki E. , de Carvalho E. , Pedersen G.F.
Published: July 2014

The performance of an antenna cancellation technique for a multiple‐input–multiple‐output (MIMO) full‐duplex system that is based on null‐steering beamforming and antenna polarisation diversity is investigated. A practical implementation of a symmetric antenna topology comprising three dual‐polarised patch antennas operating at 2.4 GHz is described. The measurement results show an average of 60 dB self‐interference cancellation over 200 MHz bandwidth. Moreover, a decoupling level of up to 22 dB is achieved for MIMO multiplexing using antenna polarisation diversity. The performance evaluation of the proposed technique was performed by simulation and measurement and the results have good agreement.
Low onset voltage of GaN on Si Schottky barrier diode using various recess depths
Authors: Park Youngrak , Kim Jung‐Jin , Chang Woojin , Jang Hyun‐Gyu , Na Jeho , Lee Hyunsoo , Jun Chi‐Hoon , Cha Ho‐young , Mun Jae Kyoung , Ko Sang Choon , Nam Eun Soo
Published: July 2014

A low onset voltage AlGaN/GaN diode with a width of 14 mm is achieved. The recess depth of the AlGaN layer is responsible for the low onset voltage. In comparison with the conventional non‐recessed diode, the onset voltage reduces by 45% along with a decrease of reverse leakage current by about one order of magnitude.
Compact ACS‐fed monopole antenna with rectangular SRRs for tri‐band operation
Authors: Kang Le , Wang Hao , Wang Xin Huai , Shi Xiaowei
Published: July 2014

A compact uniplanar monopole antenna is presented for tri‐band operation. The antenna is fed by an asymmetric coplanar strip (ACS), which can provide an effective way to reduce the antenna size. Two rectangular split‐ring resonators (SRRs) are etched on the radiating patch to achieve a tri‐band resonant characteristic and good performance of interference suppression. The proposed antenna with a total size of 32 × 12 mm2 has been constructed and tested. The measured results indicate that the designed antenna has 10 dB impedance bandwidths of 340 MHz (2.36–2.70 MHz), 390 MHz (3.35–2.74 GHz) and 1110 MHz (5.01–6.12 GHz), which meet the requirements of the 2.4/5.2/5.8 GHz wireless local area network (WLAN) and 2.5/3.5/5.5 GHz worldwide interoperability for microwave access (WiMAX) applications.
Open platform, 32‐channel, portable, data‐logger with 32 PGA control lines for wearable medical device development
Authors: Gargiulo G.D. , Bifulco P. , Cesarelli M. , McEwan A. , Wabnitz A.
Published: July 2014

A compact isolated low‐power 32‐channel 16‐bit data‐logging system around an NXP ARM processor (LPC1768) and four of the linear technology octal analogue‐to‐digital converters (ADCs) LTC1857/58/59 is designed. The system requires only 250 mA when powered at 5 V to run at full power (including a capacitive 2.8 inch touch‐screen display and 32 Gb SHDC SD memory card). The sample rate is configurable up to 1 k SPS per channel as well as voltage dynamic input up to ±10 V; additionally, 32 chip select lines (SPI protocol) individually addressable and controllable while sampling to configure user‐designed programmable gain amplifiers (PGAs) are available. Collaboration is being sought to improve the software capabilities, particularly to enrich the very basic user interface and to add wireless connectivity. The code is available (under the GPL licence) at our repository, the gerber file to reproduce the PCB is available (on the As‐Is basis) on request. The galvanic isolation between the power supply data connection and ADC channels makes the data‐logger also compatible with the main powered PCs, hence it is suitable for the implementation of medical devices at least for the prototyping and initial testing stages.
Energy‐efficient charge‐average switching DAC with floating capacitors for SAR ADC
Authors: Kim Ju Eon , Cho Seong‐Jin , Kim Yong Sin , Lee Seok , Baek Kwang‐Hyun
Published: July 2014

An energy‐efficient capacitor switching digital‐to‐analogue converter (DAC) is proposed for successive‐approximation register analogue‐to‐digital converters (SAR ADCs). The proposed charge‐average switching with floating capacitors (CASFCs) DAC disconnects the most significant bit (MSB) capacitors from the capacitor array after determining the MSB. The switching energy of the proposed CASFC DAC is lower than that of the recently published DAC, because the CAS technique is only employed in the CASFC DAC, while both the traditional and CAS methods are used in the previous DAC depending on inputs. In addition, the energy during the reset period is also minimised because the floated MSB capacitors do not consume the reset energy. The CASFC DAC reduces the switching energy with and without reset by 64.4 and 37.5%, respectively, compared with the aforementioned previous DAC.
Compact, high gain, hetero‐composite Nd:YVO4/SiC thin disk amplifier with advanced thermal management
Authors: Newburgh G.A. , Dubinskii M.
Published: July 2014

A thermally advanced, Nd:YVO4 amplifier at 1064 nm based on an 800 µm‐thick Nd:YVO­4 gain layer bonded to a silicon carbide (SiC) prism is demonstrated. The amplifier was tested in the ‘master oscillator–power amplifier’ configuration, where both the seed source and the amplifier were operated in a quasi‐continuous‐wave regime. The hetero‐composite Nd:YVO4/SiC gain element pumped by an 808 nm laser diode bar stack amplified the seed power in a range of 1–55 W with a gain of 4–2.6, respectively. The temperature profile of the gain element measured by a thermal camera indicated the maximum observed temperature excursion at pump saturation intensity to be only 27°C.
Wideband hybrid circularly polarised rectangular dielectric resonator antenna excited by modified cross‐slot
Authors: Zou Meng , Pan Jin
Published: July 2014

A wideband circularly polarised (CP) rectangular dielectric resonator antenna (DRA) based on the concept of a hybrid antenna is presented. In this design, the modified cross‐slot simultaneously performs the functions of an effective radiator and the feeding structure of the rectangular dielectric resonator (DR). By properly designing the structure parameters of the DRA, the resonances of the modified cross‐slot and the DR can be merged to obtain a wide CP bandwidth. A prototype antenna is designed, fabricated and measured, and a wide 3 dB axial ratio bandwidth of 24.6% is achieved.
Electrical conductivity measurement in Thiel‐embalmed tissue model: relevance to radiofrequency ablation
Authors: Wang Zhigang , Luo Hongyan , Nick M. , Gueorguieva M. , Andre P. , Baker R.T. , McLean D. , Brown S. , Cuschieri A.
Published: July 2014

Thiel‐embalmed human cadaveric specimens are used widely for biomedical scientific investigation. This Letter reports electrical impedance measurements of Thiel‐embalming solutions from 1 Hz to 32 MHz. Compared with other solutions studied, Thiel solution has the lowest impedance throughout the test spectrum. The electrical conductivity of a Thiel‐embalmed liver sample exhibited a relatively flat frequency response from 100 to 500 kHz, which is the frequency range used for electro‐surgery and radiofrequency tumour ablation (RFA). It measured 5 Sm−1 compared with 0.22 Sm−1 obtained from ex‐vivo fresh pig liver. Using finite element modelling and experimental evaluation, the ablation zone obtained from the Thiel‐embalmed liver sample was extremely small due to its much higher conductivity. Hence, it is concluded that Thiel‐embalmed tissue cannot be used as a reliable model for RFA evaluation.
Cooperative jamming and power allocation with untrusty two‐way relay nodes
Authors: Long Hang , Xiang Wei , Wang Jing , Zhang Yueying , Wang Wenbo
Published: July 2014

This study investigates the security of the two‐way relaying system with untrusty relay nodes. Cooperative jamming schemes are considered for bi‐directional secrecy communications. The transmit power of each source node is divided into two parts corresponding to the user and jamming signals, respectively. Two different assumptions of the jamming signals are considered. When the jamming signals are a priori known at the two source nodes, closed‐form power allocation expressions at two source nodes are derived. Under the assumption of unknown jamming signals, it is proven that the cooperative jamming is useless for the system secrecy capacity, because that all the power should be allocated to the user signals at each source node. Relay selection is also investigated based on the analysis of cooperative jamming. Simulation results are presented to compare the system secrecy capacities under the two jamming signal assumptions.
Efficient interference cancellation detector for asynchronous upstream optical code division multiple access‐passive optical network with mixed Poisson–Gaussian noise
Authors: Fathallah Habib , Bentrcia Abdelouahab , Seleem Hussein
Published: July 2014

Optical code division multiple access (OCDMA) is a promising candidate for next generation passive optical networks (NG‐PON). OCDMA‐PON can potentially provide all customers with a Gb/s‐class BW upstream with inherent flexibility. Unfortunately OCDMA suffers from multiple access interference (MAI) and various detection noises. In this study, the authors consider developing efficient interference cancellation detection under mixed Poisson–Gaussian noise. The latter is more realistic than considering Gaussian or Poisson noise alone. The authors first start by developing a maximum likelihood framework of the detection process under Gaussian, Poisson and Poisson–Gaussian noises, respectively. Then, the authors develop the proposed interference cancellation detector for the Poisson–Gaussian noise case after deriving the conventional expectation‐maximisation (EM) detector for the Poisson noise case. Finally, the authors simulate the proposed detector and compare it to the projected parallel interference cancellation, EM and other detectors to validate its superiority and enhanced performance.
Same rate and pattern recognition search of orthogonal variable spreading factor code tree for wideband code division multiple access networks
Authors: Balyan Vipin , Saini Davinder S.
Published: July 2014

Orthogonal variable spreading factor‐based code division multiple access systems allocate vacant codes when new call(s) arrive. This study proposes a same rate assignment scheme which allocates a new call to most favourable code in the region crowded by same rate calls. This does not add to blocked codes because of previous calls but utilise the unused scattered capacity created by previous calls. A vacant code whose parent code is handling maximum number of ongoing calls of same rate is the most favourable code for new call assignment under that sub tree. This reduces higher rate blocking because of scattering of lower rate calls due to the fact that same rate calls will be assigned in the same portion of code tree. If a tie occurs for two parent codes it is resolved using pattern recognition of codes. In the proposed scheme, the most favourable search starts from higher layers that reduce number of code searches before assignment significantly. The proposed single code and multi code schemes are compared with other schemes based on code blocking probability, throughput and number of code searches required before assignment. Simulation results indicate that the proposed scheme outperforms other schemes for various traffic distributions.
Gaussian doubly dirty compound multiple‐access channel with partial side information at the transmitters
Authors: Monemizadeh Mostafa , Bahmani Elham , Abed Hodtani Ghosheh , Seyedin Seyed Alireza
Published: July 2014

In this study, the authors study a two‐user Gaussian doubly dirty compound multiple‐access channel with partial side information (GDD‐CMAC‐PSI) where two independent additive interference signals are considered, each one known non‐causally and partially to one of the encoders but unknown to either of the receivers. This channel, first, can model two users communicating with two base stations suffering from interference, and second, includes many previously studied channels as its special cases. For such a communication scenario, first, a general capacity outer bound is derived. Depending on the values of cross link gains, they classify the channel into three classes: weak, strong and mixed GDD‐CMAC‐PSI. Next, assuming that the interference signals have infinite variances, they obtain capacity outer bounds for these classes. Then, an achievable sum‐rate is derived for the GDD‐CMAC‐PSI using Costa's strategy and thereby, they show that when both interference signals have infinite variances, this achievable sum‐rate vanishes. Later, by utilising the lattice strategies and deriving achievable rate regions, independent of the interference powers, they show that in contrast with Costa's strategy, lattice‐strategies can achieve positive rates. Finally, depending on signal‐to‐noise ratio gaps at receivers, various achievable rates are obtained.
Achieving strong security based on fountain code with coset pre‐coding
Authors: Yi Ming , Ji Xinsheng , Huang Kaizhi , Wen Hong , Wu Bin
Published: July 2014

This study proposes an approach for achieving strong communication security based on explosive fountain code with coset pre‐coding, where both main and wire‐tap channels are memoryless binary erasure channels. Coset pre‐coding is used to prevent the eavesdroppers from intercepting the confidential information from the leaked bits. Further, an explosive fountain code is designed to ensure the reliability and low information leakage. By this way, the proposed approach can keep strong security and reliability when the erasure probability of the main channel is slightly lower than that of the wire‐tap channel. Extensive simulations are conducted to verify the correctness and effectiveness of the approach.
Unequal error protection by partial superposition transmission using low‐density parity‐check codes
Authors: Huang Kechao , Liang Chulong , Ma Xiao , Bai Baoming
Published: July 2014

In this study, the authors consider designing low‐density parity‐check (LDPC) coded modulation systems to achieve unequal error protection (UEP). They propose a new UEP approach by partial superposition transmission (PST) called UEP‐by‐PST. In the UEP‐by‐PST system, the information sequence is distinguished as two parts, the more important data (MID) and the less important data (LID), both of which are coded with LDPC codes. The codeword that corresponds to the MID is superimposed on the codeword that corresponds to the LID. The system performance can be analysed by using discretised density evolution. Also proposed in this study is a criterion from a practical point of view to compare the efficiencies of different UEP approaches. Numerical results show that, over both additive white Gaussian noise channels and uncorrelated Rayleigh fading channels, (i) UEP‐by‐PST provides higher coding gain for the MID compared with the traditional equal error protection approach, but with negligible performance loss for the LID; and (ii) UEP‐by‐PST is more efficient with the proposed practical criterion than the UEP approach in the digital video broadcasting system.
On feasibility of linear interference alignment for single‐input–single‐output multi‐frequency interference channel
Authors: Du Guang‐long , Zou Wei‐xia , Zhou Zheng , Liu Jian‐han
Published: July 2014

This study explores the feasibility of linear interference alignment (IA) for a (M × M, 1)K system with multi‐frequency independent channels. The authors prove that number of users K ≤ 2M − 2 is a necessary condition for (M × M, 1)K multi‐frequency IA system, which is less than that of (M × M, 1)K multiple‐input–multiple‐output system (i.e. K ≤ 2M − 1). The conclusion can be extended to all cases with the diagonal channel matrix. They also reveal that the traditional frequency division multiplexing method is inefficient in spectrum utilisation. They apply max‐SINR (signal to interference plus noise ratio) and iterative IA algorithms and the author's simulation results verify that IA algorithms work well in (M × M, 1)2M–2 IA system.
Robust position control of a lab helicopter under wind disturbances
Authors: Liu Hao , Wang Xiafu , Zhong Yisheng
Published: July 2014

Flight performances of unmanned helicopters can be affected by wind gusts especially when they are carrying out aggressive mission. In this study, robust position control problem under aggressive manoeuvres is investigated in the presence of time‐varying wind disturbances for a lab helicopter. A robust controller is designed in two steps: first, a nominal static linear feedback controller is applied to obtain desired tracking for the nominal system; then, a robust compensator is introduced to restrain the influences of parameter uncertainties, non‐linear uncertainties and external wind disturbances. It is proven that the position tracking errors of the closed‐loop system can be guaranteed to converge to a neighbourhood of the origin with designated boundary. Experimental results on the 3‐degrees of freedom helicopter confirm the effectiveness of this method.
Modelling and observer‐based H∞ controller design for networked control systems
Authors: Wang Yu‐Long , Han Qing‐Long
Published: July 2014

This study is concerned with modelling and observer‐based H∞ controller design for a continuous‐time networked control system with network‐induced delays and packet dropouts. A new model for an observer‐based networked control system is first established by proposing a linear estimation‐based delay compensation method. Then some controller design criteria are obtained by constructing an interval time‐varying delay decomposition‐based Lyapunov functional. A new bounding inequality is introduced to transfer non‐linear matrix inequalities into a solvable optimisation problem. A numerical example is given to illustrate the merits and effectiveness of the obtained results.
Gradient‐based iterative algorithm for a class of the coupled matrix equations related to control systems
Authors: Ding Feng , Zhang Huamin
Published: July 2014

By constructing an objective function and using the gradient search, a gradient‐based iteration is established for solving the coupled matrix equations Ai XBi  = Fi, i  = 1, 2, …, p. The authors prove that the gradient solution is convergent for any initial values. By analysing the spectral radius of the iterative matrix, the authors obtain an optimal convergence factor. An example is provided to illustrate the effectiveness of the proposed algorithm and to testify the conclusions established in this study.