The eccentric short-period orbit of the supergiant fast X-ray transient HD 74194 (=LM Vel)

There is a reasonable chance of finding a (probably X-ray) pulsar in a short-period orbit around the galactic center. Such a pulsar can provide a test distinguishing a central black hole from a supermassive object or spinar. It also makes available a good clock in a region of space in which GM/Rc2 is much larger than solar system values, thus allowing strong-field tests of general relativity.

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Interfacial properties of GaSb/InAs superlattices

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100149969 ◽

1993 ◽

Vol 51 ◽

pp. 826-827

Author(s):

M. E. Twigg ◽

B. R. Bennett ◽

J. R. Waterman ◽

J. L. Davis ◽

B. V. Shanabrook ◽

...

Keyword(s):

Gaas Substrate ◽

Molecular Beam ◽

Infrared Detector ◽

Interfacial Properties ◽

Ex Situ ◽

X Ray Diffraction ◽

Absorption Coefficients ◽

X Ray ◽

Short Period ◽

High Optical Absorption

Recently, the GaSb/InAs superlattice system has received renewed attention. The interest stems from a model demonstrating that short period Ga1-xInxSb/InAs superlattices will have both a band gap less than 100 meV and high optical absorption coefficients, principal requirements for infrared detector applications. Because this superlattice system contains two species of cations and anions, it is possible to prepare either InSb-like or GaAs-like interfaces. As such, the system presents a unique opportunity to examine interfacial properties.We used molecular beam epitaxy (MBE) to prepare an extensive set of GaSb/InAs superlattices grown on an GaSb buffer, which, in turn had been grown on a (100) GaAs substrate. Through appropriate shutter sequences, the interfaces were directed to assume either an InSb-like or GaAs-like character. These superlattices were then studied with a variety of ex-situ probes such as x-ray diffraction and Raman spectroscopy. These probes confirmed that, indeed, predominantly InSb-like and GaAs-like interfaces had been achieved.

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Properties of Faint X-ray Activity of XTE J1908+094 in 2019

Galaxies ◽

10.3390/galaxies9020025 ◽

2021 ◽

Vol 9 (2) ◽

pp. 25

Author(s):

Debjit Chatterjee ◽

Arghajit Jana ◽

Kaushik Chatterjee ◽

Riya Bhowmick ◽

Sujoy Kumar Nath ◽

...

Keyword(s):

Black Hole ◽

Temporal Analysis ◽

Power Density Spectrum ◽

Periodic Oscillations ◽

Telescope Array ◽

Density Spectrum ◽

X Ray ◽

Black Hole Candidate ◽

Short Period ◽

Spectral State

We study the properties of the faint X-ray activity of Galactic transient black hole candidate XTE J1908+094 during its 2019 outburst. Here, we report the results of detailed spectral and temporal analysis during this outburst using observations from Nuclear Spectroscopic Telescope Array (NuSTAR). We have not observed any quasi-periodic-oscillations (QPOs) in the power density spectrum (PDS). The spectral study suggests that the source remained in the softer (more precisely, in the soft–intermediate) spectral state during this short period of X-ray activity. We notice a faint but broad Fe Kα emission line at around 6.5 keV. We also estimate the probable mass of the black hole to be 6.5−0.7+0.5M⊙, with 90% confidence.

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Combined HREELS, Raman and X-ray diffraction study of short-period GaAsAlAs superlattices

Surface Science ◽

10.1016/s0039-6028(96)01048-5 ◽

1996 ◽

Vol 368 (1-3) ◽

pp. 185-189 ◽

Cited By ~ 3

Author(s):

T Tsuruoka ◽

Y Uehara ◽

S Ushioda ◽

T Kojima ◽

Y Sugiyama

Keyword(s):

Diffraction Study ◽

X Ray Diffraction ◽

X Ray ◽

Short Period

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Magnetic assessment and modelling of the Aramis undulator beamline

Journal of Synchrotron Radiation ◽

10.1107/s1600577518002205 ◽

2018 ◽

Vol 25 (3) ◽

pp. 686-705 ◽

Cited By ~ 3

Author(s):

M. Calvi ◽

C. Camenzuli ◽

R. Ganter ◽

N. Sammut ◽

Th. Schmidt

Keyword(s):

Magnetic Properties ◽

Magnetic Measurement ◽

Hall Probe ◽

Measurement Equipment ◽

Series Production ◽

Close Collaboration ◽

X Ray ◽

Short Period ◽

Reduction Methods ◽

Paul Scherrer

Within the SwissFEL project at the Paul Scherrer Institute (PSI), the hard X-ray line (Aramis) has been equipped with short-period in-vacuum undulators, known as the U15 series. The undulator design has been developed within the institute itself, while the prototyping and the series production have been implemented through a close collaboration with a Swiss industrial partner, Max Daetwyler AG, and several subcontractors. The magnetic measurement system has been built at PSI, together with all the data analysis tools. The Hall probe has been designed for PSI by the Swiss company SENIS. In this paper the general concepts of both the mechanical and the magnetic properties of the U15 series of undulators are presented. A description of the magnetic measurement equipment is given and the results of the magnetic measurement campaign are reported. Lastly, the data reduction methods and the associated models are presented and their actual implementation in the control system is detailed.

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X-ray image based pneumonia classification using convolutional neural networks

ACCENTS Transactions on Image Processing and Computer Vision ◽

10.19101/tipcv.2020.618050 ◽

2020 ◽

Vol 6 (20) ◽

pp. 54-67

Author(s):

Sarah Badr AlSumairi ◽

Mohamed Maher Ben Ismail

Keyword(s):

Neural Networks ◽

Convolutional Neural Networks ◽

Network Architecture ◽

Data Augmentation ◽

Critical Factor ◽

Classification Problem ◽

X Rays ◽

X Ray ◽

Erroneous Decision ◽

Short Period

Pneumonia is an infectious disease of the lungs. About one third to one half of pneumonia cases are caused by bacteria. Early diagnosis is a critical factor for a successful treatment process. Typically, the disease can be diagnosed by a radiologist using chest X-ray images. In fact, chest X-rays are currently the best available method for diagnosing pneumonia. However, the recognition of pneumonia symptoms is a challenging task that relies on the availability of expert radiologists. Such “human” diagnosis can be inaccurate and subjective due to lack of clarity and erroneous decision. Moreover, the error can increase more if the physician is requested to analyze tens of X-rays within a short period of time. Therefore, Computer-Aided Diagnosis (CAD) systems were introduced to support and assist physicians and make their efforts more productive. In this paper, we investigate, design, implement and assess customized Convolutional Neural Networks to overcome the image-based Pneumonia classification problem. Namely, ResNet-50 and DenseNet-161 models were inherited to design customized deep network architecture and improve the overall pneumonia classification accuracy. Moreover, data augmentation was deployed and associated with standard datasets to assess the proposed models. Besides, standard performance measures were used to validate and evaluate the proposed system.

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High Resolution X-Ray Diffraction Investigations of Si/SiGe Quantum Well Structures and Si/Ge Short-Period Superlattices

Acta Physica Polonica A ◽

10.12693/aphyspola.84.475 ◽

1993 ◽

Vol 84 (3) ◽

pp. 475-489

Author(s):

G. Bauer ◽

E. Koppensteiner ◽

P. Hamberger ◽

J. Nützel ◽

G. Abstreiter ◽

...

Keyword(s):

High Resolution ◽

Quantum Well ◽

X Ray Diffraction ◽

Quantum Well Structures ◽

X Ray ◽

Short Period ◽

Short Period Superlattices

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Structural Properties of InAs/AlSb Superlattices

MRS Proceedings ◽

10.1557/proc-379-493 ◽

1995 ◽

Vol 379 ◽

Author(s):

B. Jenichen ◽

H. Neuroth ◽

B. Brar ◽

H. Kroemer

Keyword(s):

Buffer Layer ◽

Peak Shift ◽

Lattice Parameter ◽

Structural Quality ◽

Inhomogeneous Deformation ◽

X Ray ◽

Peak Broadening ◽

Short Period ◽

Intensity Ratios ◽

Highly Correlated

ABSTRACTShort-period (InAs)6/(AlSb)6 superlattices (SL) with AlAs-like and InSb-like interfaces (IF) grown on a relaxed AlSb buffer layer are studied by X-ray reflectivity and diffractometry measurements. Reflectivity measurements reveal average IF roughnesses between 0.6 and 1.0 nm. Measurements of the diffuse scattering show that the roughness is highly correlated from layer to layer. Triple crystal area scans illustrate that the inhomogeneous deformation of the buffer layer leads to a certain symmetric peak broadening. In the case of AlAs-like IFs an additional broadening of the SL peaks reveals lattice parameter gradients over the superlattice. This asymmetric peak broadening may be attributed to a further relaxation of the superlattice, which is inhomogeneous with depth. The diffusion of As into the AlSb layers leads to a peak shift and modifies the intensity ratios of the different satellite reflections. The best structural quality is achieved for superlattices with InSb-like IFs.

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The Formation of Compact Objects in Binary Systems

Symposium - International Astronomical Union ◽

10.1017/s0074180900073848 ◽

1981 ◽

Vol 93 ◽

pp. 155-175 ◽

Cited By ~ 1

Author(s):

E.P.J. van den Heuvel

Keyword(s):

Mass Transfer ◽

Binary Systems ◽

Compact Star ◽

Compact Objects ◽

Binary Interaction ◽

X Ray ◽

Tidal Forces ◽

Short Period ◽

Wide Range ◽

X Ray Binaries

The various ways in which compact objects (neutron stars and black holes) can be formed in interacting binary systems are qualitatively outlined on the basis of the three major modes of binary interaction identified by Webbink (1980). Massive interacting binary systems (M1 ≳ 10–12 M⊙) are, after the first phase of mass transfer expected to leave as remnants:(i) compact stars in massive binary systems (mass ≳ 10 M⊙) with a wide range of orbital periods, as remnants of quasi-conservative mass transfer; these systems later evolve into massive X-ray binaries.(ii) short-period compact star binaries (P ~ 1–2 days) in which the companion may be more massive or less massive than the compact object; these systems have high runaway velocities (≳ 100 km/sec) and start out with highly eccentric orbits, which are rapidly circularized by tidal forces; they may later evolve into low-mass X-ray binaries;(iii) single runaway compact objects with space velocities of ~ 102 to 4.102 km/sec; these are expected to be the most numerous compact remnants.Compact star binaries may also form from Cataclysmic binaries or wide binaries in which an O-Ne-Mg white dwarf is driven over the Chandrasekhar limit by accretion.

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Interface study and performance of large layer pair ultra-short period W/B4C X-ray multilayer

10.1063/1.4917934 ◽

2015 ◽

Author(s):

P. C. Pradhan ◽

M. Nayak ◽

P. Mondal ◽

G. S. Lodha

Keyword(s):

X Ray ◽

Short Period ◽

And Performance ◽

Interface Study

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