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関連する概念動画

X-ray Crystallography02:18

X-ray Crystallography

The size of the unit cell and the arrangement of atoms in a crystal may be determined from measurements of the diffraction of X-rays by the crystal, termed X-ray crystallography.
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
Detection of Black Holes01:10

Detection of Black Holes

Although black holes were theoretically postulated in the 1920s, they remained outside the domain of observational astronomy until the 1970s.
Their closest cousins are neutron stars, which are composed almost entirely of neutrons packed against each other, making them extremely dense. A neutron star has the same mass as the Sun but its diameter is only a few kilometers. Therefore, the escape velocity from their surface is close to the speed of light.
Not until the 1960s, when the first neutron...
NMR Spectrometers: Resolution and Error Correction01:14

NMR Spectrometers: Resolution and Error Correction

When magnetic nuclei in a sample achieve resonance and undergo relaxation, the signal detected in NMR is an approximately exponential free induction decay. Fourier transform of an exponential decay yields a Lorentzian peak in the frequency domain. Lorentzian peaks in an NMR spectrum are defined by their amplitude, full width at half maximum, and position, where the peak width is governed by the spin-spin relaxation time alone. In real experiments, however, the applied magnetic field is rendered...
X-ray Imaging01:24

X-ray Imaging

German physicist Wilhelm Röntgen (1845–1923) was experimenting with electrical current when he discovered that a mysterious and invisible "ray" would pass through his flesh but leave an outline of his bones on a screen coated with a metal compound. In 1895, Röntgen made the first durable record of the internal parts of a living human: an "X-ray" image (as it came to be called) of his wife’s hand. Scientists worldwide quickly began their own experiments with X-rays, and by 1900, X-ray was widely...
Difference from Background: Limit of Detection01:05

Difference from Background: Limit of Detection

The limit of detection (LOD) is the smallest amount of analyte that can be distinguished from the background noise. The LOD value corresponds to the concentration at which the analyte signal is three times larger than the standard deviation of the blank signal. Below this value, the analyte signal cannot be differentiated from the background noise. It is calculated by dividing the calibration slope by 3 times the standard deviation of the blank signals.
The LOD indicates the presence or absence...
Atomic Emission Spectroscopy: Interference01:30

Atomic Emission Spectroscopy: Interference

In atomic emission spectroscopy (AES), high-temperature atomizers excite a broad range of elements and molecules that generate complex emissions from sources such as oxides, hydroxides, and flame combustion products in the flame or plasma. Several strategies can be employed to minimize spectral interferences caused by overlapping emission lines or bands. These include increasing instrument resolution, choosing alternative emission lines, optimally placing the detector in low-background regions,...

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関連する実験動画

Updated: Jun 13, 2026

Applying X-ray Imaging Crystal Spectroscopy for Use as a High Temperature Plasma Diagnostic
06:46

Applying X-ray Imaging Crystal Spectroscopy for Use as a High Temperature Plasma Diagnostic

Published on: August 25, 2016

銀河外の硬いX線背景を解明する.

Mushotzky1, Cowie, Barger

  • 1NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA.

Nature
|April 13, 2000
PubMed
まとめ
この要約は機械生成です。

研究者達は,何十年にもわたって宇宙の謎であった,硬いX線背景の源を特定した. ディープ・チャンドラによる観測により,これらの源が背景と一致していることが明らかになった.

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Synchrotron X-ray Microdiffraction and Fluorescence Imaging of Mineral and Rock Samples
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Synchrotron X-ray Microdiffraction and Fluorescence Imaging of Mineral and Rock Samples

Published on: June 19, 2018

Troubleshooting and Quality Assurance in Hyperpolarized Xenon Magnetic Resonance Imaging: Tools for High-Quality Image Acquisition
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Troubleshooting and Quality Assurance in Hyperpolarized Xenon Magnetic Resonance Imaging: Tools for High-Quality Image Acquisition

Published on: January 5, 2024

関連する実験動画

Last Updated: Jun 13, 2026

Applying X-ray Imaging Crystal Spectroscopy for Use as a High Temperature Plasma Diagnostic
06:46

Applying X-ray Imaging Crystal Spectroscopy for Use as a High Temperature Plasma Diagnostic

Published on: August 25, 2016

Synchrotron X-ray Microdiffraction and Fluorescence Imaging of Mineral and Rock Samples
10:12

Synchrotron X-ray Microdiffraction and Fluorescence Imaging of Mineral and Rock Samples

Published on: June 19, 2018

Troubleshooting and Quality Assurance in Hyperpolarized Xenon Magnetic Resonance Imaging: Tools for High-Quality Image Acquisition
09:55

Troubleshooting and Quality Assurance in Hyperpolarized Xenon Magnetic Resonance Imaging: Tools for High-Quality Image Acquisition

Published on: January 5, 2024

科学分野:

  • 宇宙X線天文学の宇宙X線
  • 天体物理学 天体物理学
  • 高エネルギー天体物理学

背景:

  • 硬いX線背景 (2-10 keV) の起源は,35年以上にわたって解明されていないままです.
  • 柔らかいX線背景源 (主にクエザール) が特定されているが,そのスペクトルのエネルギー分布は全体の背景スペクトルと一致していない.

研究 の 目的:

  • 硬いX線背景の起源の謎を調査し解明する.
  • 硬いX線背景に寄与する源を特定し,その性質を分析する.

主な方法:

  • 深いX線調査のために,チャンドラ衛星を利用した.
  • 検出された硬質X線源のスペクトルエネルギー分布を分析した.

主要な成果:

  • 検出されたハードX線源は,ハードX線背景の少なくとも75%を占めています.
  • これらの源の平均スペクトルエネルギー分布は,背景スペクトルとほぼ一致しています.
  • 特定された源は,明るい銀河の核,光学的に薄い物体,潜在的に活発な銀河の核,または高赤道移転クワザールと関連しています.

結論:

  • この研究は,ハードX線背景の長年の謎を大幅に解明しています.
  • 特定された情報源は,観測されたハードX線背景スペクトルの強力な説明を提供します.
  • この発見は,活発な銀河核,おそらく遮蔽された,または遠いクエーサールからの重要な貢献を示唆しています.