3,541 research outputs found
The Polonnaruwa meteorite: oxygen isotope, crystalline and biological composition
Results of X-Ray Diffraction (XRD) analysis, Triple Oxygen Isotope analysis
and Scanning Electron Microscopic (SEM) studies are presented for stone
fragments recovered from the North Central Province of Sri Lanka following a
witnessed fireball event on 29 December 2012. The existence of numerous
nitrogen depleted highly carbonaceous fossilized biological structures fused
into the rock matrix is inconsistent with recent terrestrial contamination.
Oxygen isotope results compare well with those of CI and CI-like chondrites but
are inconsistent with the fulgurite hypothesis.Comment: 7 pages, 7 figures, 4 table
Synthesis of racemic and chiral BEDT-TTF derivatives possessing hydroxy groups and their achiral and chiral charge transfer complexes
Chiral molecular crystals built up by chiral molecules without inversion centers have attracted much interest owing to their versatile functionalities related to optical, magnetic, and electrical properties. However, there is a difficulty in chiral crystal growth due to the lack of symmetry. Therefore, we made the molecular design to introduce intermolecular hydrogen bonds in chiral crystals. Racemic and enantiopure bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) derivatives possessing hydroxymethyl groups as the source of hydrogen bonds were designed. The novel racemic trans-vic-(hydroxymethyl)(methyl)-BEDT-TTF 1, and racemic and enantiopure trans-vic-bis(hydroxymethyl)-BEDT-TTF 2 were synthesized. Moreover, the preparations, crystal structure analyses, and electrical resistivity measurements of the novel achiral charge transfer salt θ21-[(S,S)-2]3[(R,R)-2]3(ClO4)2 and the chiral salt α’-[(R,R)-2]ClO4(H2O) were carried out. In the former θ21-[(S,S)-2]3[(R,R)-2]3(ClO4)2, there are two sets of three crystallographically independent donor molecules [(S,S)-2]2[(R,R)-2] in a unit cell, where the two sets are related by an inversion center. The latter α’-[(R,R)-2]ClO4(H2O) is the chiral salt with included solvent H2O, which is not isostructural with the reported chiral salt α’-[(S,S)-2]ClO4 without H2O, but has a similar donor arrangement. According to the molecular design by introduction of hydroxy groups and a ClO4− anion, many intermediate-strength intermolecular hydrogen bonds (2.6–3.0 Å) were observed in these crystals between electron donor molecules, anions, and included H2O solvent, which improve the crystallinity and facilitate the extraction of physical properties. Both salts are semiconductors with relatively low resistivities at room temperature and activation energies of 1.2 ohm cm with Ea = 86 meV for θ21-[(S,S)-2]3[(R,R)-2]3(ClO4)2 and 0.6 ohm cm with Ea = 140 meV for α'-[(R,R)-2]2ClO4(H2O), respectively. The variety of donor arrangements, θ21 and two kinds of α’-types, and their electrical conductivities of charge transfer complexes based upon the racemic and enantiopure (S,S)-2, and (R,R)-2 donors originates not only from the chirality, but also the introduced intermolecular hydrogen bonds involving the hydroxymethyl groups, perchlorate anion, and the included solvent H2O
Terahertz Microstrip Elevated Stack Antenna Technology on GaN-on-Low Resistivity Silicon Substrates for TMIC
In this paper we demonstrate a THz microstrip stack antenna on GaN-on-low resistivity silicon substrates (ρ < 40 Ω.cm). To reduce losses caused by the substrate and to enhance performance of the integrated antenna at THz frequencies, the driven patch is shielded by silicon nitride and gold in addition to a layer of benzocyclobutene (BCB). A second circular patch is elevated in air using gold posts, making this design a stack configuration. The demonstrated antenna shows a measured resonance frequency in agreement with the modeling at 0.27 THz and a measured S11 as low as −18 dB was obtained. A directivity, gain and radiation efficiency of 8.3 dB, 3.4 dB, and 32% respectively was exhibited from the 3D EM model. To the authors' knowledge, this is the first demonstrated THz integrated microstrip stack antenna for TMIC (THz Monolithic Integrated Circuits) technology; the developed technology is suitable for high performance III-V material on low resistivity/high dielectric substrates
Prikaz knjige: Zorislav Kaleb - Djelovanje kaznene presude na parnični postupak /Vizura, Zagreb, 2008./
Nedavno je u izdanju nakladničke kuće Vizura objavljena knjiga mr. sc. Zorislava Kaleba, suca Kaznenog odjela Općinskog suda u Zagrebu, Djelovanje kaznene presude na parnični postupak s podnaslovom Vezanost parničnog suda za pravomoćnu presudu kaznenog suda. Knjiga Djelovanje kaznene presude na parnični postupak predstavlja autorov izra¬đeni i obranjeni magistarski rad na poslijediplomskom znanstvenom studiju iz trgovačkog prava i prava društava na Pravnom fakultetu Sveučilišta u Zagrebu dana 4. travnja 2006. godine na temu Vezanost parničnog suda za pravomoćnu presudu kaznenog suda pred Povjerenstvom koje su činili akademik Jakša Barbić, predsjednik Povjerenstva, prof. dr. se. Mihajlo Dika kao mentor, te prof. dr. se. Davor Krapac i dr. se. Branko Vukmir kao članovi Povjerenstva. Isti rad je autor u međuvremenu dijelom prilagodio radi objave kao monografije, a također je unio i izmjene koje su se u međuvremenu dogodile našem pozitivnom zakonodavstvu. U knjizi se obrađuje odnos između parničnog i kaznenog postupka, vezanost par¬ničnog suda za pravomoćnu osuđujuću presudu kaznenog suda po tužbi iz istog događaja, prejudicijelno djelovanje presude kaznenog suda na parnični postupak, djelovanje kaznene presude kao pravno relevantne činjenice u parničnom postupku, prekid postupka po od¬luci suda u parničnom postupku, donošenje pravomoćne kaznene presude kao razlog za ponavljanje parničnog postupka, te neki zaključni prijedlozi de legeferenda. Rad dijelom komparativno obrađuje istu materiju i u nekim drugim zakonodavstvima u opsegu koliko je to zanimljivo za našeg praktičara. Knjiga je rezultat dvogodišnjeg istraživanja autora prvenstveno odluka Županijskog suda u Zagrebu i Vrhovnog suda Republike Hrvatske, te potom i dostupnih odluka drugih domaćih i stranih sudova
Psychometric and Behavioral Measures of Central Auditory Function: The Relationship between Dichotic Listening and Digit Span Tasks
We hypothesized that the Digit Span (DS) subtest and component tasks (Wechsler, 1991) would show strong relationships with a dichotic listening test (Musiek, 1983). In two sets of archival clinical data (N = 74 and N = 51) we demonstrated that: (a) individuals with central auditory deficits had lower DS scores, F(1, 72) = 7.34, p = .008; η2 = .09; and (b) left-ear dichotic deficits impacted forward span, F(2, 48) = 8.45, p = .001. Right-ear dichotic listening performance also accounted for significant vari-ance in digit forward span (R2 = 0.17, p = .003). While limited in scope, the studies conclude that forward but not reverse span performance is strongly related to dichotic listening, and can serve as a marker for possible central auditory deficits
Psychometric and Behavioral Measures of Central Auditory Function: The Relationship between Dichotic Listening and Digit Span Tasks
We hypothesized that the Digit Span (DS) subtest and component tasks (Wechsler, 1991) would show strong relationships with a dichotic listening test (Musiek, 1983). In two sets of archival clinical data (N = 74 and N = 51) we demonstrated that: (a) individuals with central auditory deficits had lower DS scores, F(1, 72) = 7.34, p = .008; η2 = .09; and (b) left-ear dichotic deficits impacted forward span, F(2, 48) = 8.45, p = .001. Right-ear dichotic listening performance also accounted for significant vari-ance in digit forward span (R2 = 0.17, p = .003). While limited in scope, the studies conclude that forward but not reverse span performance is strongly related to dichotic listening, and can serve as a marker for possible central auditory deficits
Control of threshold voltage in E-mode and D-mode GaN-on-Si metal-insulator-semiconductor heterostructure field effect transistors by in-situ fluorine doping of atomic layer deposition Al2O3 gate dielectrics
We report the modification and control of threshold voltage in enhancement and depletion mode AlGaN/GaN metal-insulator-semiconductor heterostructure field effect transistors through the use of in-situ fluorine doping of atomic layer deposition Al2O3. Uniform distribution of F ions throughout the oxide thickness are achievable, with a doping level of up to 5.5 × 1019 cm−3 as quantified by secondary ion mass spectrometry. This fluorine doping level reduces capacitive hysteretic effects when exploited in GaN metal-oxide-semiconductor capacitors. The fluorine doping and forming gas anneal also induces an average positive threshold voltage shift of between 0.75 and 1.36 V in both enhancement mode and depletion mode GaN-based transistors compared with the undoped gate oxide via a reduction of positive fixed charge in the gate oxide from +4.67 × 1012 cm−2 to −6.60 × 1012 cm−2. The application of this process in GaN based power transistors advances the realisation of normally off, high power, high speed devices
Mesoscopic Fermi gas in a harmonic trap
We study the thermodynamical properties of a mesoscopic Fermi gas in view of
recent possibilities to trap ultracold atoms in a harmonic potential. We focus
on the effects of shell closure for finite small atom numbers. The dependence
of the chemical potential, the specific heat and the density distribution on
particle number and temperature is obtained. Isotropic and anisotropic traps
are compared. Possibilities of experimental observations are discussed.Comment: 8 pages, 9 eps-figures included, Revtex, submitted to Phys. Rev. A,
minor changes to figures and captions, corrected typo
Cohort profile: the avon longitudinal study of parents and children: ALSPAC mothers cohort
The Avon Longitudinal Study of Children and Parents (ALSPAC) was established to understand how genetic and environmental characteristics influence health and development in parents and children. All pregnant women resident in a defined area in the South West of England, with an expected date of delivery between 1st April 1991 and 31st December 1992, were eligible and 13 761 women (contributing 13 867 pregnancies) were recruited. These women have been followed over the last 19–22 years and have completed up to 20 questionnaires, have had detailed data abstracted from their medical records and have information on any cancer diagnoses and deaths through record linkage. A follow-up assessment was completed 17–18 years postnatal at which anthropometry, blood pressure, fat, lean and bone mass and carotid intima media thickness were assessed, and a fasting blood sample taken. The second follow-up clinic, which additionally measures cognitive function, physical capability, physical activity (with accelerometer) and wrist bone architecture, is underway and two further assessments with similar measurements will take place over the next 5 years. There is a detailed biobank that includes DNA, with genome-wide data available on >10 000, stored serum and plasma taken repeatedly since pregnancy and other samples; a wide range of data on completed biospecimen assays are available. Details of how to access these data are provided in this cohort profile
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