Jove
Visualize
联系我们
JoVE
x logofacebook logolinkedin logoyoutube logo
关于 JoVE
概览领导团队博客JoVE 帮助中心
作者
出版流程编辑委员会范围与政策同行评审常见问题投稿
图书馆员
用户评价订阅访问资源图书馆顾问委员会常见问题
研究
JoVE JournalMethods CollectionsJoVE Encyclopedia of Experiments存档
教育
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab Manual教师资源中心教师网站
使用条款与条件
隐私政策
政策

相关概念视频

NMR Spectrometers: Radiofrequency Pulses and Pulse Sequences01:17

NMR Spectrometers: Radiofrequency Pulses and Pulse Sequences

763
A pulse is a short burst of radio waves distributed over a range of frequencies that simultaneously excites all the nuclei in the sample. Upon passing a radio frequency pulse along the x-axis, the nuclei absorb energy corresponding to their Larmor frequencies and achieve resonance. This shifts the net magnetization vector from the z-axis toward the transverse plane. This angle of rotation of the magnetization vector, or the flip angle, is proportional to the duration and intensity of the pulse.
763
Types of Radioactivity03:23

Types of Radioactivity

16.6K
The most common types of radioactivity are α decay, β decay, γ decay, neutron emission, and electron capture.
Alpha (α) decay is the emission of an α particle from the nucleus. For example, polonium-210 undergoes α decay:
16.6K
Super-resolution Fluorescence Microscopy01:37

Super-resolution Fluorescence Microscopy

6.9K
Super-resolution fluorescence microscopy (SRFM) provides a better resolution than conventional fluorescence microscopy by reducing the point spread function (PSF). PSF is the light intensity distribution from a point that causes it to appear blurred. Due to PSF, each fluorescing point appears bigger than its actual size, and it is the PSF interference of nearby fluorophores that causes the blurred image. Various approaches to achieving higher resolution through SRFM have recently been...
6.9K
The Electromagnetic Spectrum02:37

The Electromagnetic Spectrum

52.6K
The electromagnetic spectrum consists of all the types of electromagnetic radiation arranged according to their frequency and wavelength. Each of the various colors of visible light has specific frequencies and wavelengths associated with them, and you can see that visible light makes up only a small portion of the electromagnetic spectrum. Because the technologies developed to work in various parts of the electromagnetic spectrum are different, for reasons of convenience and historical...
52.6K
Atomic Fluorescence Spectroscopy01:29

Atomic Fluorescence Spectroscopy

247
Atomic fluorescence spectroscopy (AFS) is an analytical technique that involves the electronic transitions of atoms in a flame, furnace, or plasma being excited by electromagnetic (EM) radiation. When these atoms absorb energy, they become excited and subsequently release energy as they return to their original state. This emitted light, or "fluorescence," is observed at a right angle to the incident beam. Both absorption and emission processes transpire at distinct wavelengths, which...
247
Atomic Nuclei: Magnetic Resonance01:05

Atomic Nuclei: Magnetic Resonance

632
The number of nuclear spins aligned in the lower energy state is slightly greater than those in the higher energy state. In the presence of an external magnetic field, as the spins precess at the Larmor frequency, the excess population results in a net magnetization oriented along the z axis. When a pulse or a short burst of radio waves at the Larmor frequency is applied along the x axis, the coupling of frequencies causes resonance and flips the nuclear spins of the excess population from the...
632

您也可能阅读

相关文章

通过共同作者、期刊和引用图与本文相关的文章。

排序
Same author

A repeating fast radio burst source in a globular cluster.

Nature·2022
Same author

Author Correction: A bimodal burst energy distribution of a repeating fast radio burst source.

Nature·2021
Same author

A bimodal burst energy distribution of a repeating fast radio burst source.

Nature·2021
Same author

Chromatic periodic activity down to 120 megahertz in a fast radio burst.

Nature·2021
Same author

Asymmetric mass ratios for bright double neutron-star mergers.

Nature·2020
Same author

A repeating fast radio burst source localized to a nearby spiral galaxy.

Nature·2020

相关实验视频

Updated: Jun 7, 2025

Simulating Imaging of Large Scale Radio Arrays on the Lunar Surface
06:14

Simulating Imaging of Large Scale Radio Arrays on the Lunar Surface

Published on: July 30, 2020

4.8K

快速的无线电爆发就是快速的无线电爆发.

E Petroff1,2, J W T Hessels1,2, D R Lorimer3,4

  • 1Anton Pannekoek Institute, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.

The astronomy and astrophysics review
|November 15, 2024
PubMed
概括
此摘要是机器生成的。

快速无线电爆发 (FRB) 是一种发光的,银河系外的无线电瞬态. 新的广场射电望远镜将能够探测到更多的FRB,进步我们对其起源的理解,并作为宇宙探测器使用.

关键词:
快速无线电爆发快速的无线电爆发.脉冲星是一个脉冲星.无线电天文学 无线电天文学暂时的 暂时的 暂时的

更多相关视频

Femtosecond Laser Filaments for Use in Sub-Diffraction-Limited Imaging and Remote Sensing
06:16

Femtosecond Laser Filaments for Use in Sub-Diffraction-Limited Imaging and Remote Sensing

Published on: April 25, 2019

7.5K
Ultrafast Time-resolved Near-IR Stimulated Raman Measurements of Functional π-conjugate Systems
09:57

Ultrafast Time-resolved Near-IR Stimulated Raman Measurements of Functional π-conjugate Systems

Published on: February 10, 2020

7.1K

相关实验视频

Last Updated: Jun 7, 2025

Simulating Imaging of Large Scale Radio Arrays on the Lunar Surface
06:14

Simulating Imaging of Large Scale Radio Arrays on the Lunar Surface

Published on: July 30, 2020

4.8K
Femtosecond Laser Filaments for Use in Sub-Diffraction-Limited Imaging and Remote Sensing
06:16

Femtosecond Laser Filaments for Use in Sub-Diffraction-Limited Imaging and Remote Sensing

Published on: April 25, 2019

7.5K
Ultrafast Time-resolved Near-IR Stimulated Raman Measurements of Functional π-conjugate Systems
09:57

Ultrafast Time-resolved Near-IR Stimulated Raman Measurements of Functional π-conjugate Systems

Published on: February 10, 2020

7.1K

科学领域:

  • 无线电天文学 无线电天文学
  • 天体物理学 天体物理学
  • 宇宙学的宇宙学是什么?

背景情况:

  • 50多年前发现的无线电脉冲星证实了中子星的存在,并为研究极端物理提供了一个工具.
  • 快速无线电爆发 (FRB) 是最近发现的,高度发光的无线电短暂物源于银河系外,看起来类似于脉冲脉冲,但具有显著的分散延迟.
  • 虽然大多数FRB都是短暂的,但重复的FRB表明有一个持久的中央引擎,促使人们对它们的起源和天体物理影响进行研究.

研究的目的:

  • 为新进入该领域的天文学家提供快速无线电爆发 (FRB) 的观测和理论方面的简单介绍.
  • 突出FRB的潜力,作为探测银河系外媒和宇宙极端物理学的探测器,类似于脉冲星.
  • 讨论新的广场无线电仪器对未来FRB发现率和研究的影响.

主要方法:

  • 来自射电望远镜的观测数据的审查,包括脉冲星调查和专门的FRB搜索.
  • 关于FRB生成的拟议机制及其源的特性,进行理论讨论.
  • 分析望远镜视野在限制当前FRB检测速率方面的作用.

主要成果:

  • FRB是众多的,估计全天空事件率约为每分钟一个可检测到的爆发.
  • 目前FRB发现的局限性主要是由于现有射电望远镜的视野很小.
  • 新的广场仪器的出现有望显著提高FRB检测率,可能每天多次.

结论:

  • 新仪器所促进的检测率的提高将对区分FRB起源的各种理论模型至关重要.
  • FRB提供了一个独特的机会来研究星际介质,并在极端环境中测试基本物理.
  • 该领域正处于了解短时间无线电瞬态的重大突破的尖端.