Articles de revues : « Ray Frontier »

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Shin, Shik. « Frontier of Soft-X-ray Spectroscopy ». hamon 17, n^o 1 (2007) : 59–62. http://dx.doi.org/10.5611/hamon.17.59.

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Drescher, M. « X-ray Pulses Approaching the Attosecond Frontier ». Science 291, n^o 5510 (15 février 2001) : 1923–27. http://dx.doi.org/10.1126/science.1058561.

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Kouyama, T. « Frontier in the X-ray crystallography of bacteriorhodopsin ». Seibutsu Butsuri 41, supplement (2001) : S6. http://dx.doi.org/10.2142/biophys.41.s6_2.

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Giovannelli, F., et L. Sabau-Graziati. « X-Ray Binaries : A Laboratory for Frontier Physics ». Chinese Journal of Astronomy and Astrophysics 3, S1 (31 décembre 2003) : 202–24. http://dx.doi.org/10.1088/1009-9271/3/s1/202.

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Henningsen, Arne, Matěj Bělín et Géraldine Henningsen. « New insights into the stochastic ray production frontier ». Economics Letters 156 (juillet 2017) : 18–21. http://dx.doi.org/10.1016/j.econlet.2017.04.006.

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TOIZUMI, Takahiro, Jun KATAOKA, Yoshihiro TSUBUKU, Mitsuyoshi KOBAYASHI, Yoichi YATSU, Makoto ARIMOTO, Takashi SHIMOKAWABE et al. « TSUBAME : toward the Frontier of X-ray/Gamma-ray Polarimetry in Astronomy ». TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, SPACE TECHNOLOGY JAPAN 7, ists26 (2009) : Tm_31—Tm_35. http://dx.doi.org/10.2322/tstj.7.tm_31.

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Jiang Hui, 蒋晖, et 李爱国 Li Aiguo. « X射线衍射极限纳米聚焦的前沿进展 ». Acta Optica Sinica 42, n^o 11 (2022) : 1134004. http://dx.doi.org/10.3788/aos202242.1134004.

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Qi, Yue, et Xiaolin Li. « On Imposing ESG Constraints of Portfolio Selection for Sustainable Investment and Comparing the Efficient Frontiers in the Weight Space ». SAGE Open 10, n^o 4 (octobre 2020) : 215824402097507. http://dx.doi.org/10.1177/2158244020975070.

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Sustainable investment is typically fulfilled by screening of environmental, social, and governance (ESG); the screening strategies are practical and expedite sustainable-investment development. However, the strategies typically build portfolios by a list of good stocks and ignore portfolio completeness. Moreover, there has been limited literature to study the portfolio weights of sustainable investment in the weight space. In such an area, this article contributes to the literature as follows: We extend a conventional portfolio-selection model and impose ESG constraints. We analytically solve our model by computing the efficient frontier and prove that the frontier’s portfolio weights all lie on a ray (half line). By the ray structure, we prove that portfolio selection for sustainable investment and conventional portfolio selection fundamentally possess highly different portfolio weights. Overall, our aim is comparing the portfolio weights of sustainable portfolio selection and of conventional portfolio selection; the comparison result has been unknown until now. The result is important for sustainable investment because portfolio weights are the foundation of portfolio selection and investments. We sample the component stocks of Dow Jones Industrial Average Index from 2004 to 2013 and find that our efficient frontier and the conventional efficient frontier are quite similar. Therefore, in plain financial language, investors can still obtain risk-return performance similar to conventional portfolio selection after imposing strong ESG requirements, although the portfolio weights can be totally different. The result is both an endorsement and a reminder for sustainable investment.

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Tanaka, Hitoshi, Makina Yabashi, Mitsuru Nagasono, Tadashi Togashi et Tetsuya Ishikawa. « Science Frontier Developed by X-ray Free-Electron Laser ». IEEJ Transactions on Electronics, Information and Systems 130, n^o 10 (2010) : 1698–705. http://dx.doi.org/10.1541/ieejeiss.130.1698.

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Eckert, Dominique. « X-raying the Hubble Frontier Fields cluster Abell 2744 ». Proceedings of the International Astronomical Union 11, A29B (août 2015) : 760–63. http://dx.doi.org/10.1017/s1743921316006748.

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AbstractAbell 2744 was the first HFF cluster completed. It displays a fascinating complexity in its distribution of dark and luminous matter, which led to its nickname of the Pandora cluster. In late 2014 we obtained a deep (110 ks) observation of this cluster with XMM-Newton, with the aim of making a detailed comparison between the optical, X-ray and lensing properties of this system. The new X-ray observation unveiled the presence of three hot gas filaments extending on scales of several Mpc and connected to the cluster core. The X-ray structures coincide spatially with the distribution of galaxies and dark matter and provide strong evidence for the existence of the elusive warm-hot intergalactic medium (WHIM). The new observation also reveals the complexity of the thermodynamic structure of the cluster core and a probable shock front associated with the radio relic located 1 Mpc NW of the cluster core.

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Yashiro, Wataru, Wolfgang Voegeli et Hiroyuki Kudo. « Exploring Frontiers of 4D X-ray Tomography ». Applied Sciences 11, n^o 19 (23 septembre 2021) : 8868. http://dx.doi.org/10.3390/app11198868.

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In the 4D world of three-dimensional (3D) space plus time that we live in, there is a vast blue ocean in the spatio-temporal domain of micrometers and milliseconds that has never been accessed even with the most advanced measurement technology, and it is expected to be full of various non-equilibrium phenomena. In this paper, we review recent advances in synchrotron hard X-ray tomography we have made that can be used to explore the 4D frontier.

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Ridge, Martin. « Frederick Jackson Turner, Ray Allen Billington, and American Frontier History ». Western Historical Quarterly 19, n^o 1 (janvier 1988) : 4. http://dx.doi.org/10.2307/969790.

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Hwu, Y., et G. Margaritondo. « Phase contrast : the frontier of x-ray and electron imaging ». Journal of Physics D : Applied Physics 46, n^o 49 (22 novembre 2013) : 490301. http://dx.doi.org/10.1088/0022-3727/46/49/490301.

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Kitou, Shunsuke, Yuto Hosogi, Ryo Kitaura, Toshio Naito, Toshikazu Nakamura et Hiroshi Sawa. « Direct Observation of Molecular Orbitals Using Synchrotron X-ray Diffraction ». Crystals 10, n^o 11 (3 novembre 2020) : 998. http://dx.doi.org/10.3390/cryst10110998.

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The physical properties of molecular crystals are governed by the frontier orbitals of molecules. A molecular orbital, which is formed by superposing the atomic orbitals of constituent elements, has complicated degrees of freedom in the crystal because of the influence of electron correlation and crystal field. Therefore, in general, it is difficult to experimentally observe the whole picture of a frontier orbital. Here, we introduce a new method called “core differential Fourier synthesis” (CDFS) using synchrotron X-ray diffraction to observe the valence electron density in materials. By observing the valence electrons occupied in molecular orbitals, the orbital state can be directly determined in a real space. In this study, we applied the CDFS method to molecular materials such as diamond, C60 fullerene, (MV)I2, and (TMTTF)2X. Our results not only demonstrate the typical orbital states in some materials, but also provide a new method for studying intramolecular degrees of freedom.

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Aquila, A., M. Drescher, T. Laarmann, M. Barthelmeß, H. N. Chapman et S. Bajt. « Moving the Frontier of Quantum Control into the Soft X-Ray Spectrum ». International Journal of Optics 2011 (2011) : 1–4. http://dx.doi.org/10.1155/2011/417075.

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The femtosecond nature of X-ray free electron laser (FEL) pulses opens up exciting research possibilities in time-resolved studies including femtosecond photoemission and diffraction. The recent developments of seeding X-ray FELs extend their capabilities by creating stable, temporally coherent, and repeatable pulses. This in turn opens the possibility of spectral engineering soft X-ray pulses to use as a probe for the control of quantum dynamics. We propose a method for extending coherent control pulse-shaping techniques to the soft X-ray spectral range by using a reflective geometry 4f pulse shaper. This method is based on recent developments in asymmetrically cut multilayer optic technology and piezoelectric substrates.

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Luque, Pedro De La Torre, Daniele Gaggero, Dario Grasso et Antonio Marinelli. « Gamma Rays and Neutrinos from the Galactic Plane at the PeV frontier ». Journal of Physics : Conference Series 2429, n^o 1 (1 février 2023) : 012036. http://dx.doi.org/10.1088/1742-6596/2429/1/012036.

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Abstract The Tibet ASγ experiment recently reported the observation of a diffuse gamma-ray emission from the Galactic plane with energy up to the PeV. This finding seems to be confirmed by LHAASO preliminary results. Both measurements provide the first evidence of a diffuse gamma-ray emission throughout the Galaxy up to such high energies. These results have relevant implications for neutrino astronomy since they strengthen the expectation that a neutrino diffuse emission from the Galactic plane could soon be discovered by IceCube and KM3NeT. To explore this possibility we use physically motivated numerical models which reasonably describe the observed gamma-ray diffuse emission angular distribution and spectral energy distribution from few GeV up to the PeV under the hypothesis that is mostly originated by the cosmic ray population of the Galaxy. We will discuss the possible detectability of the associated neutrino emission and the valuable implications it may have for understanding the origin and propagation of cosmic rays.

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Kato, Mariko, Hideyuki Saio et Izumi Hachisu. « Pre-maximum Evolution of the Classical Nova YZ Reticuli ». Research Notes of the AAS 6, n^o 12 (7 décembre 2022) : 258. http://dx.doi.org/10.3847/2515-5172/aca8af.

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Abstract The pre-maximum evolution of a nova is the last frontier in studying such objects. YZ Reticuli 2020 is the only nova whose X-ray flash was detected. The X-ray flash occurs immediately after the onset of thermonuclear runaway, so its physical properties impose severe constraints on the nova model. We discuss what we can learn from the early phase observations.

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Błachucki, Wojciech, Anna Wach, Joanna Czapla-Masztafiak, Mickaël Delcey, Christopher Arrell, Rafał Fanselow, Pavle Juranić et al. « Approaching the Attosecond Frontier of Dynamics in Matter with the Concept of X-ray Chronoscopy ». Applied Sciences 12, n^o 3 (8 février 2022) : 1721. http://dx.doi.org/10.3390/app12031721.

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X-ray free electron lasers (XFELs) have provided scientists opportunities to study matter with unprecedented temporal and spatial resolutions. However, access to the attosecond domain (i.e., below 1 femtosecond) remains elusive. Herein, a time-dependent experimental concept is theorized, allowing us to track ultrafast processes in matter with sub-fs resolution. The proposed X-ray chronoscopy approach exploits the state-of-the-art developments in terahertz streaking to measure the time structure of X-ray pulses with ultrahigh temporal resolution. The sub-femtosecond dynamics of the saturable X-ray absorption process is simulated. The employed rate equation model confirms that the X-ray-induced mechanisms leading to X-ray transparency can be probed via measurement of an X-ray pulse time structure.

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Yashiro, Wataru, Xiaoyu Liang, Wolfgang Voegeli, Etsuo Arakawa, Tetsuroh Shirasawa, Kentaro Kajiwara, Katsuya Fujii, Koh Hashimoto et Hiroyuki Kudo. « Millisecond-Order Temporal-Resolution Synchrotron X-ray Tomography without Sample Rotation ». Journal of Physics : Conference Series 2380, n^o 1 (1 décembre 2022) : 012121. http://dx.doi.org/10.1088/1742-6596/2380/1/012121.

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Abstract A multi-beam optics consisting of curved crystals with blades for a white synchrotron X-ray beam from a bending magnet was developed, and millisecond-order temporal-resolution X-ray tomography with a voxel size of 20 μm was successfully realized without sample rotation. The multi-beam optics opens the spatio-temporal frontier of X-ray tomography for unrepeatable and nonequilibrium systems and is expected to be applied to various fields in materials and life sciences.

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Jones, C., R. van Weeren, G. Ogrean et W. Forman. « FM 22. Mapping the Frontier Fields with Chandra X-ray Observations ». Proceedings of the International Astronomical Union 11, A29B (août 2015) : 758–59. http://dx.doi.org/10.1017/s1743921316006736.

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AbstractChandra has deeply observed the clusters and parallel fields in four Frontier Fields. These observations allow us to dramatically improve our understanding of cluster mergers by comparing the detailed mapping of the hot cluster gas with high resolution mass maps and by identifying merger shocks and cold fronts. In merging clusters, relativistic particles can be re-accelerated to produce radio relics. A comparison of lensing maps and Chandra images allows us to determine the cluster morphology and dynamical state and if there are offsets between the dark matter and the hot gas.

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Schmalholz, D. W. « American Pathfinders : Using Ray Bradbury's Martian Chronicles to Teach Frontier History ». OAH Magazine of History 13, n^o 2 (1 janvier 1999) : 44–48. http://dx.doi.org/10.1093/maghis/13.2.44.

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Bonazzi, Tiziano. « Frederick Jackson Turner's Frontier Thesis and the Self-Consciousness of America ». Journal of American Studies 27, n^o 2 (août 1993) : 149–71. http://dx.doi.org/10.1017/s0021875800031509.

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In their work on Turner's formative period, Ray A. Billington and Fulmer Mood have shown that the Frontier Thesis, formulated in 1893 in “The Significance of the Frontier in American History,” is not so much a brilliant early effort by a young scholar as a mature study in which Turner gave his ideas an organization that proved to be final. During the rest of his life he developed but never disclaimed or modified them. Billington and Mood also add that the Frontier Thesis is meant to test a new approach to history that Turner had been developing since the beginning of his academic career. We can fully understand it, then, only by setting it within the framework of the assumptions and goals of his 1891 essay, “The Significance of History,” Turner's only attempt to sketch a philosophy of history.

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García-Suárez, Federico, Gabriela Pérez-Quesada et Carlos Molina Riccetto. « Rangeland cattle production in Uruguay : Single-output versus multi-output efficiency measures ». Economía Agraria y Recursos Naturales 22, n^o 1 (22 juin 2022) : 69–88. http://dx.doi.org/10.7201/earn.2022.01.04.

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Rangeland cattle production is the largest agricultural sector of Uruguay. Ranches produce up to three products (beef, sheep-meat, and wool) usually combined into an equivalent meat (EM) index. The objective is to compare the empirical results from the estimation of a single output stochastic production frontier (SPF) and a multi-output stochastic ray frontier (SRF) to provide insights on the useof the EM index to evaluate ranches performance. Results show similar efficiency scores. The average level of TE is 0.769 for the SPF and 0.779 for the SRF. We cannot discard EM index as a simple measure of combined production.

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Su, Y., R. P. Kraft, P. E. J. Nulsen, C. Jones, T. J. Maccarone, F. Mernier, L. Lovisari et al. « Extended X-Ray Study of M49 : The Frontier of the Virgo Cluster ». Astronomical Journal 158, n^o 1 (7 juin 2019) : 6. http://dx.doi.org/10.3847/1538-3881/ab1d51.

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GRABOWSKI, RICHARD, STEVEN KRAFT, CARL PASURKA et HASSAN Y. ALY. « A ray-homothetic production frontier and efficiency : grain farms in Southern Illinois ». European Review of Agricultural Economics 17, n^o 4 (1990) : 435–48. http://dx.doi.org/10.1093/erae/17.4.435.

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Rahaman, Majidul, Ramij Raja, Abhirup Datta, Jack O. Burns, Brian Alden et David Rapetti. « An X-ray and radio study of the Hubble Frontier Field cluster Abell S1063 ». Monthly Notices of the Royal Astronomical Society 505, n^o 1 (29 avril 2021) : 480–91. http://dx.doi.org/10.1093/mnras/stab1225.

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ABSTRACT We present results from Chandra X-ray observations and 325 MHz Giant Metrewave Radio Telescope (GMRT) observations of the massive and X-ray luminous cluster of galaxies Abell S1063. We report the detection of large-scale ‘excess brightness’ in the residual Chandra X-ray surface brightness map that extends at least 2.7 Mpc towards the north-east from the centre of the cluster. We also present a high fidelity X-ray flux and temperature map using Chandra archival data of 122 ks that shows the disturbed morphology in the cluster. The residual flux map shows the first observational confirmation of the merging axis proposed in earlier simulations. The average temperature within R500 is 11.7 ± 0.56 keV that makes AS1063 one of the hottest clusters in the nearby Universe. The integrated radio flux density at 325 MHz is found to be 62.0 ± 6.3 mJy. The integrated spectrum of the radio halo follows a power law with a spectral index α = −1.43 ± 0.13. The radio halo is found to be significantly under-luminous that favored for both the hadronic as well as the turbulent re-acceleration mechanism for its origin.

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Neff, David L., Philip Garcia et Robert H. Hornbaker. « Efficiency Measures Using the Ray-Homothetic Function : A Multiperiod Analysis ». Journal of Agricultural and Applied Economics 23, n^o 2 (décembre 1991) : 113–22. http://dx.doi.org/10.1017/s0081305200018239.

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AbstractRecent investigations have provided mixed assessments of farm firm efficiency. This analysis examined the efficiency of a homogeneous sample of central Illinois grain farms over a six-year period. A best-practice frontier was constructed using the ray-homothetic function, which allowed optimal farm output to vary with factor intensity. Efficiency measures were found to increase with temporal aggregation. The ray-homothetic approach was found to attribute high scale inefficiencies to larger sample farms in cases where the factor shares did not vary appreciably across farms. The findings suggest that policy recommendations regarding farm efficiency must be made with care.

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Guo, Jinghua, et Zahid Hasan. « Meeting Report : Soft-X-ray Photon-in and Photon-out Spectroscopy : New Frontier ». Synchrotron Radiation News 19, n^o 1 (mars 2006) : 16–17. http://dx.doi.org/10.1080/08940880500525036.

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Niquidet, Kurt, et Harry Nelson. « Sawmill production in the interior of British Columbia : A stochastic ray frontier approach ». Journal of Forest Economics 16, n^o 4 (décembre 2010) : 257–67. http://dx.doi.org/10.1016/j.jfe.2010.04.001.

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Gonzalez, E. J., M. Chalela, M. Jauzac, D. Eckert, M. Schaller, D. Harvey, A. Niemiec et al. « Setting the scene for BUFFALO : a study of the matter distribution in the HFF galaxy cluster MACS J0416.1−2403 and its parallel field ». Monthly Notices of the Royal Astronomical Society 494, n^o 1 (20 mars 2020) : 349–62. http://dx.doi.org/10.1093/mnras/staa745.

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ABSTRACT In the context of the Beyond Ultradeep Frontier Fields And Legacy Observations (BUFFALO) survey, we present a new analysis of the merging galaxy cluster MACS J0416.1−2403 (z = 0.397) and its parallel field using Hubble Frontier Fields (HFF) data. We measure the surface mass density from a weak-lensing analysis and characterize the overall matter distribution in both the cluster and parallel fields. The surface mass distribution derived for the parallel field shows clumpy overdensities connected by filament-like structures elongated in the direction of the cluster core. We also characterize the X-ray emission in the parallel field and compare it with the lensing mass distribution. We identify five mass peaks at the >5σ level over the two fields, four of them being in the cluster one. Three of them are located close to galaxy overdensities and one is also close to an excess in the X-ray emission. Nevertheless, two of them have neither optical nor X-ray counterpart and are located close to the edges of the field of view, thus further studies are needed to confirm them as substructures. Finally, we compare our results with the predicted subhalo distribution of one of the Hydrangea/C-EAGLE simulated cluster. Significant differences are obtained suggesting the simulated cluster is at a more advanced evolutionary stage than MACS J0416.1−2403. Our results anticipate the upcoming BUFFALO observations that will link the two HFF fields, extending further the HST coverage.

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FUJIWARA, MAMORU. « NUCLEAR PHOTON SCIENCE WITH INVERSE-COMPTON SCATTERING ». International Journal of Modern Physics E 18, n^o 10 (novembre 2009) : 1970–75. http://dx.doi.org/10.1142/s021830130901410x.

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Recent developments of the synchroton radiation facilities and intense lasers are now guiding us to a new research frontier with probes of a high energy GeV photon beam and an intense and short pulse MeV γ-ray beam. New directions of the science developments with photo-nuclear reactions are discussed. The inverse Compton γ -ray has two good advantages for searching for a microscopic quantum world; they are 1) good emmitance and 2) high linear and circular polarizations. With these advantages, photon beams in the energy range from MeV to GeV are used for studying hadron structure, nuclear structure, astrophysics, materials science, as well as for applying medical science.

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Jay, Raphael M., Sebastian Eckert, Mattis Fondell, Piter S. Miedema, Jesper Norell, Annette Pietzsch, Wilson Quevedo, Johannes Niskanen, Kristjan Kunnus et Alexander Föhlisch. « The nature of frontier orbitals under systematic ligand exchange in (pseudo-)octahedral Fe(ii) complexes ». Physical Chemistry Chemical Physics 20, n^o 44 (2018) : 27745–51. http://dx.doi.org/10.1039/c8cp04341h.

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Kagay, Donald J. « The Sephardic Frontier : The "Reconquista" and the Jewish Community in Medieval Iberia. Jonathan Ray ». Speculum 82, n^o 4 (octobre 2007) : 1028–30. http://dx.doi.org/10.1017/s0038713400011829.

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Almer, Jon, Peter Chupas, Brian Stephenson, Dave Tiede, Stefan Vogt, Linda Young, Paul Evans, John Parise et Bob Suter. « Emerging Opportunities in High-Energy X-ray Science : The Diffraction-Limited Storage Ring Frontier ». Synchrotron Radiation News 29, n^o 1 (2 janvier 2016) : 12–13. http://dx.doi.org/10.1080/08940886.2016.1124675.

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Schoenlein, Robert, Thomas Elsaesser, Karsten Holldack, Zhirong Huang, Henry Kapteyn, Margaret Murnane et Michael Woerner. « Recent advances in ultrafast X-ray sources ». Philosophical Transactions of the Royal Society A : Mathematical, Physical and Engineering Sciences 377, n^o 2145 (avril 2019) : 20180384. http://dx.doi.org/10.1098/rsta.2018.0384.

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Over more than a century, X-rays have transformed our understanding of the fundamental structure of matter and have been an indispensable tool for chemistry, physics, biology, materials science and related fields. Recent advances in ultrafast X-ray sources operating in the femtosecond to attosecond regimes have opened an important new frontier in X-ray science. These advances now enable: (i) sensitive probing of structural dynamics in matter on the fundamental timescales of atomic motion, (ii) element-specific probing of electronic structure and charge dynamics on fundamental timescales of electronic motion, and (iii) powerful new approaches for unravelling the coupling between electronic and atomic structural dynamics that underpin the properties and function of matter. Most notable is the recent realization of X-ray free-electron lasers (XFELs) with numerous new XFEL facilities in operation or under development worldwide. Advances in XFELs are complemented by advances in synchrotron-based and table-top laser-plasma X-ray sources now operating in the femtosecond regime, and laser-based high-order harmonic XUV sources operating in the attosecond regime. This article is part of the theme issue ‘Measurement of ultrafast electronic and structural dynamics with X-rays’.

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Cereti, Carlo Giovanni, Mehdi Mousavi Nia et Mohammad Reza Neʿmati. « Ray and Pahlaw in the Context of Sasanian Iran ». Journal of Persianate Studies 14, n^o 1-2 (10 août 2022) : 6–30. http://dx.doi.org/10.1163/18747167-bja10016.

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Abstract Ray—located near present-day Tehran—is among the most important historical areas in Iran and the plains to the south of Tehran have always been densely inhabited and intensely cultivated thanks to the waters coming from Mount Tochal and the Alborz Mountains. Historical records and archeological data for the early history of the city in the Median, Achæmenid, Seleucid, and even Parthian periods are not exhaustive. In the present study, an attempt is made to bring together primary and secondary sources to define better the role that the province of Ray played during the Sasanian period, during which it was host, among others, to a huge military camp crucial to manning the northern and eastern frontier. Combined archeological and historical evidence shows that Ray has played an important and pivotal role in the history of Iran from the first years of the formation of the Sasanian Empire to the very last years of the empire, leaving a lasting memory in the Islamic literary tradition.

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Wernet, Philippe. « Chemical interactions and dynamics with femtosecond X-ray spectroscopy and the role of X-ray free-electron lasers ». Philosophical Transactions of the Royal Society A : Mathematical, Physical and Engineering Sciences 377, n^o 2145 (avril 2019) : 20170464. http://dx.doi.org/10.1098/rsta.2017.0464.

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X-ray free-electron lasers with intense, tuneable and short-pulse X-ray radiation are transformative tools for the investigation of transition-metal complexes and metalloproteins. This becomes apparent in particular when combining the experimental observables from X-ray spectroscopy with modern theoretical tools for calculations of electronic structures and X-ray spectra from first principles. The combination gives new insights into how charge and spin densities change in chemical reactions and how they determine reactivity. This is demonstrated for the investigations of structural dynamics with metal K-edge absorption spectroscopy, spin states in excited-state dynamics with metal 3p-3d exchange interactions, the frontier-orbital interactions in dissociation and substitution reactions with metal-specific X-ray spectroscopy, and studies of metal oxidation states with femtosecond pulses for ‘probe-before-destroy’ spectroscopy. The role of X-ray free-electron lasers is addressed with thoughts about how they enable ‘bringing back together’ different aspects of the same problem and this is thought to go beyond a conventional review paper where these aspects are formulated in italic font type in a prequel, an interlude and in a sequel. This article is part of the theme issue ‘Measurement of ultrafast electronic and structural dynamics with X-rays'.

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Abdel-Sattar, Nour E. A., Abeer M. El-Naggar et M. S. A. Abdel-Mottaleb. « Novel Thiazole Derivatives of Medicinal Potential : Synthesis and Modeling ». Journal of Chemistry 2017 (2017) : 1–11. http://dx.doi.org/10.1155/2017/4102796.

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This paper reports on the synthesis of new thiazole derivatives that could be profitably exploited in medical treatment of tumors. Molecular electronic structures have been modeled within density function theory (DFT) framework. Reactivity indices obtained from the frontier orbital energies as well as electrostatic potential energy maps are discussed and correlated with the molecular structure. X-ray crystallographic data of one of the new compounds is measured and used to support and verify the theoretical results.

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Yang, Z. S., P. Y. Huang, J. J. Chen, Y. M. Chen, T. Gao, H. F. Chai et C. S. Zhao. « Synthesis, crystal structure, and DFT study of 1-(2-bromobenzyl)- 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole ». Журнал структурной химии 62, n^o 6 (2021) : 997–1006. http://dx.doi.org/10.26902/jsc_id72898.

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1-(2-Bromobenzyl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole is an organic intermediate with both pyrazole heterocycle and borate functional group. In this paper, the title compound is obtained by the nucleophilic substitution reaction. The structure of the compound is confirmed by FTIR, 1H and 13C NMR spectroscopy, and MS. At the same time, the single crystal of the title compound is measured by X-ray diffraction and is subjected to the crystallographic and conformational analysis. The molecular structure is further calculated using density functional theory (DFT) and compared with the X-ray diffraction value. The results of the conformational analysis indicate that the molecular structure optimized by DFT is consistent with the crystal structure determined by single crystal X-ray diffraction. In addition, the molecular electrostatic potential and frontier molecular orbitals of the title compound are further investigated by DFT, revealing molecular structure characteristics and molecular conformations.

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Radhakrishnan, Anbarasan, Anna Lakshmi Muppudathi et Kalyana Sundar Jeyaperumal. « Experimental and computational investigation with Hirshfeld surface analysis of bis(glycine) strontium dichloride trihydrate ». Materials Science-Poland 38, n^o 4 (1 décembre 2020) : 545–52. http://dx.doi.org/10.2478/msp-2020-0061.

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Abstract Good-quality semiorganic single crystals of bis(glycine) strontium dichloride trihydrate (GSC) were grown by slow evaporation technique. The lattice parameters of the grown crystal were verified through single crystal X-ray diffraction. Besides, the crystallinity of the material was analyzed with powder X-ray diffraction. The fingerprint of functional groups of this material was analyzed by FT-IR technique. The UV transparency cutoff wavelength of GSC was found to be 240 nm and the crystal exhibited 80 % transmission in the entire visible region. All intermolecular and intramolecular interactions of the grown crystal were interpreted by Hirshfeld surface analysis, and the strength of the interactions was graphically illustrated by fingerprint graphs. The intramolecular charge transfers of the crystal were assessed through frontier molecular orbital analysis.

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SIMMS, NORMAN. « The Sephardic Frontier : The Reconquista and the Jewish Community in Medieval Iberia - By Jonathan Ray ». Journal of Religious History 35, n^o 2 (24 mai 2011) : 303–4. http://dx.doi.org/10.1111/j.1467-9809.2010.01015.x.

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Yin, Xiaoling, Xiaoli Zhu, Hong Zhou, Zhuyu Li, Aimin Wang et Xiaojing Liao. « Technical efficiency of carp polyculture production in Jiangsu, China : a ray stochastic frontier production approach ». Aquaculture Research 48, n^o 4 (2 mars 2016) : 1629–37. http://dx.doi.org/10.1111/are.12998.

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Huang, P. Y., Z. S. Yang, Q. M. Wu, D. Z. Yang, J. J. Chen, H. F. Chai et C. S. Zhao. « Synthesis, crystal structure, and DFT study of methyl 3-fluoro- 5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzoate and (2-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl) (pyrrolidin-1-yl)methanone compounds ». Журнал структурной химии 62, n^o 6 (2021) : 913–20. http://dx.doi.org/10.26902/jsc_id74415.

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Methyl 3-fluoro-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzoate and (2-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)(pyrrolidin-1-yl)methanone are boric acid ester intermediates with benzene rings. In this paper, the title compounds are obtained by a three-step substitution reaction. The structures of the compounds are confirmed by FTIR, 1H and 13C NMR spectroscopy, and mass spectrometry. At the same time, single crystals of the title compounds are measured by X-ray diffraction and subjected to crystallographic and conformational analyses. The molecular structures are further calculated using density functional theory (DFT) and, which were compared with the X-ray diffraction value. The results of the conformational analysis indicate that the molecular structures optimized by DFT are consistent with the crystal structures determined by single crystal X-ray diffraction. In addition, the molecular electrostatic potential and frontier molecular orbitals of the title compounds are further investigated by DFT, and some physicochemical properties of the compounds are revealed.

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Wang, Zhe, Lingqi Wu, Yuanyuan Fang, Aihuan Dun, Jiaoling Zhao, Xueke Xu et Xiaolei Zhu. « Application of Flow Field Analysis in Ion Beam Figuring for Ultra-Smooth Machining of Monocrystalline Silicon Mirror ». Micromachines 13, n^o 2 (18 février 2022) : 318. http://dx.doi.org/10.3390/mi13020318.

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X-ray free-electron lasers are large modern scientific devices that play an important role in fields such as frontier physics and biomedicine. In this study, a light source is connected to an experimental station through beam lines, which requires numerous ultra-smooth and high-precision X-ray mirrors. Monocrystalline silicon is an ideal substrate material where ion-beam figuring is required. However, the ultra-smooth surface is damaged after the ion-beam figuring. Through an analysis of the machined surface, it is found that in the process of vacuum pumping, the impurities in the cavity adhere to the machined surface and increase the roughness after processing. Therefore, an optimized vacuum-pumping scheme is proposed. The experiment demonstrates that the original value of the processed surface roughness remains unchanged.

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Okorokov, V. A., et S. D. Campos. « Analysis of pp and p̄p elastic scatterings based on theoretical bounds in high-energy physics : An update ». International Journal of Modern Physics A 32, n^o 28n29 (19 octobre 2017) : 1750175. http://dx.doi.org/10.1142/s0217751x17501755.

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In a previous work a novel parametrization was proposed for the [Formula: see text] and [Formula: see text] total cross-sections. Here, results are presented for the updated analysis with taking into account the recent data from accelerator experiments as well as from cosmic ray measurements. The analytic parametrizations suggested within axiomatic quantum field theory (AQFT) provide the quantitative description of energy dependence of global scattering observables with robust values of fit parameters. Based on the fit results the estimations are derived for the total cross-section and the [Formula: see text] parameter in elastic [Formula: see text] scattering at various [Formula: see text] up to energy frontier [Formula: see text] PeV which can be useful for present and future hadron colliders as well as for cosmic ray measurements at ultra-high energies.

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Prabhakaran, A., M. Arockia Doss, E. Dhineshkumar et R. Rajkumar. « Synthesis, Crystal Structure and DFT Studies of 4-(2-(4,5-Dimethyl-2-(3,4,5-trimethoxyphenyl)-1H-imidazol-1-yl)ethyl)morpholine ». Asian Journal of Chemistry 33, n^o 3 (2021) : 611–16. http://dx.doi.org/10.14233/ajchem.2021.22961.

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The title compound 4-(2-(4,5-dimethyl-2-(3,4,5-trimethoxyphenyl)-1H-imidazol-1-yl)morpholine (DMTPM) was synthesized using a one-pot multicomponent approach. The molecular structure of the compound was charcterized with 1H & 13C NMR, HR-MS and single-crystal X-ray diffraction. In the ground-state, DMTPM molecular geometry was determined using the DFT based on B3LYP/6-31G(d,p) and compared to the experimental results. In addition, molecular electrostatic potential (MEP) map and molecular frontier orbitals (MFO) were performed and the results obtained were compatible with the electronic properties.

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Takahashi, Tohru. « Future Prospects of Gamma–Gamma Collider ». Reviews of Accelerator Science and Technology 10, n^o 01 (août 2019) : 215–26. http://dx.doi.org/10.1142/s1793626819300111.

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Gamma–gamma colliders based on backward Compton scattering have been discussed mainly as an option for high energy electron–positron linear colliders, aiming to play a complementary role in energy frontier physics. The flexibility of gamma-ray beam by the Compton scheme, however, allows us to apply them to physics in a wide energy range, from MeV to TeV. In this paper, we review the future prospects of gamma–gamma colliders including recent discussions about Higgs boson factories and mid- and low-energy colliders as well as the option for electron–positron linear colliders.

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Bailey, Adam H. E., Liuqi Wang, Dave N. Dewhurst, Jade R. Anderson, Lidena K. Carr et Paul A. Henson. « Geomechanical rock properties of the Officer Basin ». APPEA Journal 62, n^o 2 (13 mai 2022) : S385—S391. http://dx.doi.org/10.1071/aj21083.

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The Officer Basin spanning South Australia and Western Australia is the focus of a regional stratigraphic study being undertaken as part of the Exploring for the Future (EFTF) program, an Australian Government initiative dedicated to increasing investment in resource exploration in Australia. Despite numerous demonstrated oil and gas shows, the Officer Basin remains a frontier basin for energy exploration with significant uncertainties due to data availability. Under the EFTF Officer–Musgrave Project, Geoscience Australia acquired new geomechanical rock property data from forty core samples in five legacy stratigraphic and petroleum exploration wells that intersected Paleozoic and Neoproterozoic aged intervals. These samples were subjected to unconfined compressive rock strength tests, Brazilian tensile strength tests and laboratory ultrasonic measurements. Petrophysical properties were also characterised via X-ray computerised tomography scanning, grain density and porosity-permeability analysis. Accurate characterisation of static geomechanical rock properties through laboratory testing is essential. In the modern exploration environment, these datasets are a precompetitive resource that can simplify investment decisions in prospective frontier regions such as the Officer Basin.

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Jin, Jian-Chang, Zhao-Hui Sun, Ming-Yan Yang, Jing Wu et Xing-Hai Liu. « Synthesis, Crystal Structure, and Theoretical Studies of N-(4-((4-chlorobenzyl)oxy)phenyl)-4- (trifluoromethyl)pyrimidin-2-amine ». Journal of Chemistry 2013 (2013) : 1–5. http://dx.doi.org/10.1155/2013/521757.

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The title compound (C18H13ClF3N3O) were synthesized and recrystallized from CH3OH. The compound was characterized byH1NMR, MS, HRMS, and X-ray diffraction. The compound crystallized in the monoclinic space groupP2(1)/nwitha=8.2354(14),b=12.686(2),c=16.633(3) Å,α=90,β=97.951(3),γ=90∘,V=1721.0(5) Å3,Z=4,andR=0.0376for 1933 observed reflections withI>2σ(I).X-ray analysis reveals that intermolecular N–H⋯N interactions exist in the adjacent molecules. Theoretical calculation of the title compound was carried out with HF/6-31G(d,p), B3LYP/6-31G(d,p). The full geometry optimization was carried out using 6-31G(d,p)basis set and the frontier orbital energy. The optimized geometric bond lengths and bond angles obtained by using HF and DFT (B3LYP) showed the best agreement with the experimental data.

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Schmidt, Marius, Vukica Srajer, Robert Henning, Hyotcherl Ihee, Namrta Purwar, Jason Tenboer et Shailesh Tripathi. « Protein energy landscapes determined by five-dimensional crystallography ». Acta Crystallographica Section D Biological Crystallography 69, n^o 12 (19 novembre 2013) : 2534–42. http://dx.doi.org/10.1107/s0907444913025997.

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Free-energy landscapes decisively determine the progress of enzymatically catalyzed reactions [Cornish-Bowden (2012),Fundamentals of Enzyme Kinetics, 4th ed.]. Time-resolved macromolecular crystallography unifies transient-state kinetics with structure determination [Moffat (2001),Chem. Rev.101, 1569–1581; Schmidtet al.(2005),Methods Mol. Biol.305, 115–154; Schmidt (2008),Ultrashort Laser Pulses in Medicine and Biology] because both can be determined from the same set of X-ray data. Here, it is demonstrated how barriers of activation can be determined solely from five-dimensional crystallography, where in addition to space and time, temperature is a variable as well [Schmidtet al.(2010),Acta Cryst.A66, 198–206]. Directly linking molecular structures with barriers of activation between them allows insight into the structural nature of the barrier to be gained. Comprehensive time series of crystallographic data at 14 different temperature settings were analyzed and the entropy and enthalpy contributions to the barriers of activation were determined. One hundred years after the discovery of X-ray scattering, these results advance X-ray structure determination to a new frontier: the determination of energy landscapes.

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