87,938 research outputs found
Fluorescent Lithium Fluoride Detectors for X-Ray Projection Imaging
No full textFluorescent lithium fluoride detectors for X-ray projection imaging
F. Bonfigli, M.A. Vincenti, R.M. Montereali
ENEA, C.R. Frascati, Photonics Micro- and Nano-structures Lab.,
UTAPRAD-MNF, Via E. Fermi 45, 00044 Frascati (Rome), Italy
E. Nichelatti
ENEA, C.R. Casaccia, Optical Devices Laboratory,
UTTMAT-OTT, Via Anguillarese 301, 00123 S. Maria di Galeria, Rome, Italy
F. Somma, S. Heidari Bateni
Università degli Studi Roma Tre, Dip. di Fisica E. Amaldi, Via della Vasca Navale 84, 00146 Rome, Italy
A. Cecilia, T. Baumbach
Institute for Photon Science and Synchrotron Radiation (IPS)/ANKA, Karlsruhe Institute of Technology (KIT),
Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
Abstract
The possibility of detecting high quality images of materials, devices and biological samples in the soft and hard X-ray spectral ranges with high spatial resolution and contrast and by using simple exposing configuration is a topical task nowadays. For this purpose, we propose the use of versatile imaging detectors based on the radiation sensitivity of lithium fluoride (LiF) to extreme ultraviolet, soft and hard X-rays [1, 2]. X-rays generate stable point defects in LiF, known as colour centres (CCs), which emit broad-band photoluminescence at visible wavelengths under optical pumping. The high dynamic response of the material to the received dose together with the atomic scale of the CCs make LiF plates, in form of thin films or crystals, extremely attractive as high-spatial-resolution radiation-imaging detectors both in absorption and phase contrast imaging configurations [1, 3]. The latent images are subsequently read by using optical fluorescence microscopes, which in the case of advanced techniques can reach spatial resolutions well below 100 nm [4].
We present lensless imaging experiments in projection mode at the TOPO–TOMO beamline of the synchrotron light source Anka (Karlsruhe, Germany) by using LiF crystals and thin films irradiated in the energy range 6–40 keV. Stable fluorescent images were formed in LiF detectors by scattered X-rays after an object had been positioned between the X-ray source and the detectors. The object used in this work is the commercial test pattern X500-200-30 (Xradia, Pleasanton, CA, USA) consisting of a gold mask (thickness 3 m) deposited on a (500500) μm2 Si3N4 window (thickness 330 nm). The LiF detectors were crystals and 1 m thick polycrystalline films deposited on glass substrates. To imprint the X-ray image of the sample on the LiF detectors, the test pattern was irradiated with several exposure times between 1 s and 60 s. The X-ray micro-radiographies were optically read with a confocal laser scanning microscope (CLSM, Nikon Eclipse 80i-C1) operating in fluorescence mode. It is worth pointing out that a 1 m LiF film was able to store high-quality and well contrasted fluorescence images of the test pattern, although X-ray attenuation length in LiF varies between 0.02-12 mm for X-ray energies in the investigated range. The stored images show edge-enhancement effects that are ascribable to diffraction processes occurring during the X-ray beam propagation after its interaction with the sample. A computer simulation was performed to calculate the incoming X-ray intensity distribution across the detector. A fairly good agreement with experimental data evidences a linear optical fluorescence response of LiF-film based detectors under the investigated conditions. This linear behaviour has been confirmed by measurements of the PL signals of F2 and F3+ CCs detected with a CLSM system for several X-ray irradiation times. Further investigations are in progress to study the exploitation of solid-state LiF detectors for X-ray lensless projection imaging experiments and applications.
References
[1] G. Baldacchini, F. Bonfigli, A. Faenov, F. Flora, R.M. Montereali, A. Pace, T. Pikuz, L. Reale, J. Nanoscience and Nanotechnology 3, 6 483-486, (2003).
[2] S. Almaviva, F. Bonfigli, I. Franzini, A. Lai, R.M. Montereali, D. Pelliccia, A. Cedola, S. Lagomarsino, Appl. Phys. Lett. 89, 54102, (2006).
[3] F. Bonfigli, A. Cecilia, S. Heidari Bateni, E. Nichelatti, D. Pelliccia, F. Somma, P. Vagovic, M.A. Vincenti, T. Baumbach and R.M. Montereali, Radiation Measurements 56, 277-280, (2013).
[4] A. Ustione, A. Cricenti, F. Bonfigli, F. Flora, A. Lai, T. Marolo, R.M. Montereali, G. Baldacchini, A. Faenov, T. Pikuz, L. Reale, Appl. Phys. Lett. 88, 141107 (2006)
Towards flexible magnetoelectronics for robotic applications
No full textThis paper presents the technological advancements in the field of flexible magnetic sensors for robotics applications. Various magnetic devices (e.g. Hall, GMR, AMR and TMR) have been studied and their suitability for flexible application has been presented. Further, the system level integration of magnetic sensors in robotics is briefly discussed. With rapid development in flexible electronics, a robot with multi-functional conformable electronic skin will be possible in the foreseeable future. This will also open new avenues for a wide range of other applications including wearable electronics and interactive electronic-skin for robots and prosthesis
FIGURE 3 in A new species of Clematis L. (Ranunculaceae) from Iran
No full textFIGURE 3. Pollen morphology under scanning electron microscopy (SEM). A–C. Clematis iranica. D–F. C. orientals.Published as part of Habibi, Meisam, Nohooji, Majid Ghorbani, Baladehi, Mohammadhadi Heidari & Azizian, Dina, 2014, A new species of Clematis L. (Ranunculaceae) from Iran, pp. 99-106 in Phytotaxa 162 (2) on page 104, DOI: 10.11646/phytotaxa.162.2.4, http://zenodo.org/record/513200
Thermo-Mechanical Buckling and Non-Linear Free Oscillation of Functionally Graded Fiber-Reinforced Composite Laminated (FG-FRCL) Beams
No full textWe investigated the thermal buckling temperature and nonlinear free vibration of functionally graded fiber-reinforced composite laminated (FG-FRCL) beams. The governing nonlinear partial differential equations were derived from the Euler–Bernoulli beam theory, accounting for the von Kármán geometrical nonlinearity. Such equations were then reduced to a single equation by neglecting the axial inertia. Thus, the Galerkin method was applied to discretize the governing nonlinear partial differential equation in the form of a nonlinear ordinary differential equation, which was then solved analytically according to the He’s variational method. Three different boundary conditions were selected, namely simply, clamped and clamped-free supports. We also investigated the effect of power-index, lay-ups, and uniform temperature rise on the nonlinear natural frequency, phase trajectory and thermal buckling of FG-FRCL beams. The results showed that FG-FRCL beams featured the highest fundamental frequency, whereas composite laminated beams were characterized by the lowest fundamental frequency. Such nonlinear frequencies increase for an increased power index and a decreased temperature. Finally, it was found that FG-FRCL beams with [0/0/0] lay-ups featured the highest nonlinear natural frequency and the highest thermal buckling temperature, followed by [0/90/0] and [90/0/90] lay-ups, while a [90/90/90] lay-up featured the lowest nonlinear natural frequency and critical buckling temperature
Insights into the SAM synthetase gene family and its roles in tomato seedlings under abiotic stresses and hormone treatments
No full textS-Adenosyl-L-methionine (SAM) is a key enzyme involved in many important biological processes, such as ethylene and polyamine biosynthesis, transmethylation, and transsulfuration. Here, the SAM synthetase (SAMS) gene family was studied in ten different plants (Arabidopsis, tomato, eggplant, sunflower, Medicago truncatula, soybean, rice, barley, Triticum urartu and sorghum) with respect to its physical structure, physicochemical characteristics, and post-transcriptional and post-translational modifications. Additionally, the expression patterns of SAMS genes in tomato were analyzed based on a real-time quantitative PCR assay and an analysis of a public expression dataset. SAMS genes of monocots were more conserved according to the results of a phylogenetic analysis and the prediction of phosphorylation and glycosylation patterns. SAMS genes showed differential expression in response to abiotic stresses and exogenous hormone treatments. Solyc01g101060 was especially expressed in fruit and root tissues, while Solyc09g008280 was expressed in leaves. Additionally, our results revealed that exogenous BR and ABA treatments strongly reduced the expression of tomato SAMS genes. Our research provides new insights and clues about the role of SAMS genes. In particular, these results can inform future functional analyses aimed at revealing the molecular mechanisms underlying the functions of SAMS genes in plants
Nonlinear Dynamic Study of Non-Uniform Microscale CNTR Composite Beams Based on a Modified Couple Stress Theory
No full textThis study aims at investigating the nonlinear dynamic behavior of microscale carbon nanotube reinforced (CNTR) composite Euler-Bernoulli beams with a non-uniform cross-section, based on a modified couple stress theory (MCST). The nonlinear partial differential equations (PDEs) of motion are established based on the Von-Karman nonlinear strain-displacement relationship and Hamiltonian principle. The coupled PDEs are reduced to a single PDE, by neglecting the effects of the axial inertia and considering two different types of boundary conditions (i.e. clamped-clamped and clamped-free). At the same time, the single PDE is reverted to a nonlinear ordinary differential equation (ODE) by means of the Galerkin approach, and it is solved by using a semi-inverse method and the method of multiple time scales (MTS) for a free and forced vibration analysis, respectively. A large systematic numerical analysis is here performed to check for the sensitivity of the nonlinear response of CNTR composite beams to different boundary conditions and reinforcement parameters, with useful scientific insights for further computational investigations on the topic
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Niphargus kermanshahi Esmaeili-Rineh, Heidari, Fišer & Akmali, 2016, sp. nov.
No full textNiphargus kermanshahi sp. nov. (Figures 2–6) Material examined and type locality. Holotype, Male specimen (12 mm) from Kangarshah spring, Sahneh city, Kermanshah province, Iran, coordinates (N 34 ◦ 36 ' 53.7 ", E 47 ◦ 39 ' 44.2 "). Specimens collected by Firoozeh Heidari & Vahid Akmali; 17 May 2014. Samples are stored under catalogue number ZCRU Amph. 1023. Diagnosis. Urosomites 1–2 each with three simple setae along the dorso-median surface. Urosomite 2 with two robust setae dorso-laterally. Epimeral plates not produced. Telson deeply clefted, each lobe with three apical robust setae, one marginal robust seta and two plumose setae. Palpus of maxilla 1 short, not reaching the tip of outer lobe. Propods of gnathopods 2 broader than long, slightly subrounded. Propodus of gnathopods 2 with two short subcorner R-robust setae (so called supporting robust setae) in palmar corner. Inner ramus of uropod 1 shorter of outer ramus. Description of holotype. Total length 12 mm. Body strong and stout. Head length 16 % of body length (Figure 2). Antennae 1 (Figure 3 A). Antenna 1 is 0.43 of body length. Peduncular articles 1–3 progressively shorter; length of peduncular article 3 exceeds one half of peduncular article 2 (ratio 1: 1.72); main flagellum with 25 articles (most of which with short setae), accessory flagellum biarticulated and reaching 1 / 3 of article 4 of main flagellum; both articles with one and two simple setae, respectively (Figure 3 A). Antennae 2 (Figure 3 B). Length ratio antenna 1: 2 as 1: 0.36. Peduncular article 4 as long as article 5, articles 4 and 5 with nine and seven groups of simple setae, respectively; flagellum with 10 articles. Length of flagellum: length of peduncle article 4 + 5 as 1: 1.46. Labium (Figure 4 F) with inner lobes and fine setae on the tip of outer lobes. Maxilla 1 (Figure 3 D-E). Inner plate with two long simple setae; outer plate with seven uni-, bi-, pluri or without lateral projections; palp biarticulated, short and does not reach the tip of outer lobe, with three long distal simple setae. Maxilla 2 (Figure 4 E). Both plates with numerous long distal simple setae, inner lobe with two lateral simple setae. Mandibular palp (Figure 3 H). Ratio of mandibular palp articles 1: 2: 3 as 1: 1.86: 2.26. The proximal article has no setae, the second article with eight setae along inner margin and the third article with one group of three Asetae, three groups of B-setae, no C-setae, 15 D-setae and five E-setae. Left mandible (Figure 3 F). Incisor with five teeth, lacinia mobilis with four teeth; seven setae with lateral projections between lacinia and triturative molar. Right mandible (Figure 3 G). Incisor with four teeth, lacinia mobilis pluritooth; six setae with lateral projections between lacinia and triturative molar. Maxilliped (Figure 4 G). Inner plate short, with four distal robust setae intermixed with seven distal simple setae and four simple long lateral setae subdistally; outer plate exceeding more than half of posterior margin of palp article 2, with 12 robust setae along inner margin and four simple setae distally; palp article 3 at outer margin with two proximal and one inner and outer groups of long simple setae; palp of terminal article each with one simple seta in outer and inner margins, respectively. Nail shorter than pedestal. Gnathopod 1 (Figure 4 A–B). Coxa of gnathopod 1 same long as gnathopod 2. Coxa trapezoid, broader than long, ventral and anterior margins each with four simple setae; basis with setae on anterior and posterior margins; ischium and merus with posterior group of setae. Carpus with one group of setae anterodistally, a bulge with long simple setae; carpus 0.48 of basis length and 0.77 of propodus length. Propodus slightly longer than broad, posterior margin with five transverse rows of setae; anterior margin with three setae in two groups in addition to anterodistal group of six simple setae; palm slightly convex, defined on outer surface by one strong long corner Srobust seta accompanied laterally by two L-robust setae with lateral projections and a row of three facial M-setae, on inner surface by one short subcorner R-robust seta. Dactylus reaching posterior margin of propodus, outer and inner margins with a row of three and five simple setae, respectively, nail short, 0.29 of total dactylus length. Gnathopod 2 (Figure 4 C–D). Coxa 2 slightly trapezoid, with six setae along antero-ventral margin; basis with groups and single setae distributed along anterior and posterior margins, posterior margin of ischium and merus with one posterior group of setae. Carpus 0.53 of basis length and 0.72 propodus length. Carpus with evenly distributed simple setae posteriorly and a single group of four setae anterodistally. Propodus in gnathopod 2 larger than gnathopod 1, trapezoid shape and broader than long, posterior margin with five rows of transverse setae, anterior margin with 10 setae in two groups in addition to anterodistal group of six simple setae, palm nearly convex, defined on outer surface by one strong long corner S-robust seta accompanied laterally by two L-robust setae with lateral projections and a row of three facial M-setae, on inner surface by two short subcorner R-robust setae. Dactylus reaching posterior margin of propodus, outer and inner margins of dactylus with three and five simple setae, respectively. Nail length 0.33 of total dactylus length. Coxae 3–7 (Figure 5 A–E). Length to width ratio in coxa 3 as 1: 1.27, with 11 antero-ventro-posterior simple setae. Length to width ratio in coxa 4 as 1.7: 1, with nine antero-ventro-posterior simple setae, posterior concavity shallow and approximately 0.1 of coxa width (Figure 5 A–B). Coxa 5 with anteriorly developed lobe, with four and one simple setae in anterior and posterior lobes, respectively. Coxa 6 with anteriorly developed lobe, with two simple setae in anterior lobe, with two robust and two simple setae in posterior lobe. Coxa 7 of half-elliptic shape and a single simple seta (Figure 5 C–E). Pereopods 3–7 (Figure 5 A–E). Pereopod 3 shorter than 4 with length ratio of 1: 1.13 (Figure 5 A–B); dactylus short, with one robust seta at the base of the nail at inner margin of each of pereopods 3–4, length of dactylus 0.41 of propodus in pereopod 4. Nail shorter than pedestal (Figure 5 B). Pereopods 5: 6: 7 length ratios, 1: 1.21: 1.63, respectively. Pereopod 7 is 0.5 of body length. Pereopod bases 5– 7 respectively with six, nine and eight simple setae along posterior margins and five, six and six groups of robust setae along anterior margins (Figure 5 C–E). Ventro-anterior and ventro-posterior lobe of ischium in pereopods 5–7 developed. Ischium, merus and carpus in pereopods 5–7 with several groups of robust and simple setae along anterior and posterior margins; propodus of pereopod 7 longer than these in 5–6, dactyli of pereopods 5–7 with one robust and one short simple seta at the base of nail at inner margin, dactylus of pereopod 7 with one simple seta in outer margin, nail length of pereopod 7 is 0.27 of total dactylus length (Figure 5 C–E). Pereonites 1–6. No setae. Pereonite 7. With single simple seta postero-ventrally. Pleonites 1–3. With two simple setae along the entire dorsal surface. Epimeral plates 1–3 (Figure 6 G). Postero-ventral corner angular but not produced, posterior and ventral margins of plates 1–3 slightly to distinctly convex. Postero-ventral corner of plates 1 and 3 each with one robust seta and one simple seta; plate 2 with two robust setae and one simple seta postero-ventrally. Ventral margin of plates 2–3 with three and four robust setae, respectively. Pleopods 1–3 (Figure 6 A–C). Peduncle of pleopod 1 with one simple seta and two-hooked retinacles at distal part of inner margin (Figure 6 A); peduncle of pleopod 2 with one robust seta in dorsomedial surface, two simple setae and two-hooked retinacles at distal part of inner margin; peduncle of pleopod 3 with one simple seta at distal part of outer margin, and two-hooked retinacles at distal part of inner margin, rami of pleopods 1–3 each with 10– 12 articles (Figure 6 A–C). Urosomites 1 and 2 (Figure 2). Dorso-median surface with three simple setae per somite; urosomite 2 with two robust setae dorso-laterally. Urosomite 3 (Figure 2). No setae. Uropods 1–3 (Figure 6 D–F). Uropod 1 peduncle with six and three large robust setae along dorsolateral and dorsomedial margins, respectively. Ratio of inner to outer ramus length 1: 1.05. Inner ramus with five groups of single robust setae laterally and five robust setae distally. Outer ramus with four groups of six robust setae laterally and five robust setae distally (Figure 6 D). Outer ramus in uropod 2 longer than inner, both rami with lateral and distal long robust setae (Figure 6 E). Uropod 3 long, almost 0.25 of body length. Peduncle of uropod 3 with five robust setae and one simple seta distally. Second to first article ratio of outer ramus 1: 2.01; first article of outer ramus with five and six groups of robust and setae along inner and outer margins, respectively (Figure 6 F); distal article with marginal simple setae and six simple setae distally; inner ramus short, with one distal robust seta. Telson (Figure 6 H). Two times as long as broad, lobes slightly narrowing, each with three robust setae and one simple seta distally, and with one long robust seta and two plumose setae marginally. Etymology. The name “ kermanshahi ” refers to Kermanshah province that found samples. Phylogenetic position of the newly described species. Niphargus kermanshahi is nested within the Iranian clade and shares an ancestor with recently described N. bisitunicus (Figure 7). Four individuals of newly described species constitute a strongly supported monophylum that differs from N. bisitunicus in 0.07 % of base pairs based on Kimura two parameter distance. According to study of Hou & Li (2010), this is within the same range of divergence for 28 S gene as in well-defined Gammarus species. Hence, in addition to morphological characters, molecular data indicate that this population deserves independent species status. As the two species resemble each other in some diagnostic traits, we revised also the diagnosis of N. bisitunicus. Revised diagnosis of N. bisitunicus Esmaeili-Rineh et al. 2015 Urosomites 1–2 with one and three robust setae accompanied with two simple setae along the dorso-lateral margin. Epimeral plates distinctly produced. Telson deeply cleft, each lobe with three apical robust setae, one marginal robust seta and two marginal simple setae. Palpus of maxilla 1 normally long, and exceeds the tip of robust setae on outer lobes of maxilla 1. The shape of propods of gnathopods 1–2 is rectangular, propods tend to be longer than broad. Propods of gnathopods 1–2 each with two short subcorner R-robust setae (so called supporting robust setae). Dactyli of pereopods 3–7 with one simple seta at outer margin. Inner ramus of uropod 1 shorter of outer ramus.Published as part of Esmaeili-Rineh, Somayeh, Heidari, Firoozeh, Fišer, Cene & Akmali, Vahid, 2016, Description of new endemic species of the genus Niphargus Schiödte, 1849 (Amphipoda: Niphargidae) from a karst spring in Zagros Mountains in Iran, pp. 338-350 in Zootaxa 4126 (3) on pages 340-347, DOI: 10.11646/zootaxa.4126.3.2, http://zenodo.org/record/26515
FIGURE 1 in A new species of Clematis L. (Ranunculaceae) from Iran
No full textFIGURE 1. Clematis iranica: A. Habit. B. Flower (× 3). C. Sepal (× 10). D. Anther (× 1). E. Fruiting Head (× 3). F–G. Achene (× 2).Published as part of Habibi, Meisam, Nohooji, Majid Ghorbani, Baladehi, Mohammadhadi Heidari & Azizian, Dina, 2014, A new species of Clematis L. (Ranunculaceae) from Iran, pp. 99-106 in Phytotaxa 162 (2) on page 101, DOI: 10.11646/phytotaxa.162.2.4, http://zenodo.org/record/513200
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