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

Hess's Law03:40

Hess's Law

There are two ways to determine the amount of heat involved in a chemical change: measure it experimentally, or calculate it from other experimentally determined enthalpy changes. Some reactions are difficult, if not impossible, to investigate and make accurate measurements for experimentally. And even when a reaction is not hard to perform or measure, it is convenient to be able to determine the heat involved in a reaction without having to perform an experiment.
Henderson-Hasselbalch Equation02:48

Henderson-Hasselbalch Equation

The ionization-constant expression for a solution of a weak acid can be written as:
The Number e as a Limit01:29

The Number e as a Limit

The number e is a fundamental constant in calculus, playing a central role in describing continuous change, particularly exponential growth. It is most naturally defined through its relationship with the natural logarithm, which is the inverse of the exponential function with base e. This relationship allows e to be characterized using basic principles of differentiation rather than as an arbitrary numerical constant.A key property of the natural logarithm function, ln x, is that its derivative...
Complex Numbers01:29

Complex Numbers

The real number system cannot represent the square root of a negative number, which restricts solutions for certain equations, such as quadratics with negative discriminants. To address this, the complex number system was developed, introducing the imaginary unit i, where i = √(-1). This extension allows for the representation of all roots, including those involving negative radicands.A complex number is written in the form x + yi, where x and y are real numbers. Here, x represents the real...
Fundamental Theorem of Algebra01:30

Fundamental Theorem of Algebra

The Fundamental Theorem of Algebra is central to the study of polynomial equations, asserting that every non-constant polynomial with complex coefficients has at least one complex zero. This means that a polynomial of degree n ≥ 1, written as:  with an ≠ 0, has at least one solution in the complex number system. Since the set of real numbers is a subset of complex numbers, this theorem applies equally to polynomials with real coefficients.Building on this result, the Complete Factorization...
Complex Zeros01:29

Complex Zeros

Complex zeros are the solutions to polynomial equations that include imaginary numbers, specifically, numbers of the form a + bi, where a and b are real numbers and i is the imaginary unit defined by i2=-1. These zeros satisfy the equation P(x) = 0, where P(x) is a polynomial with real or complex coefficients. Since the complex number system includes all real numbers, it provides a complete framework for analyzing all possible roots of a polynomial.Every polynomial of degree n≥1 can be...

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

Galaxies, human eyes, and artificial neural networks.

Science (New York, N.Y.)·1995
Same author

Mapping the universe.

Science (New York, N.Y.)·1989
查看所有相关文章

相关实验视频

Updated: Jul 8, 2026

Blast Quantification Using Hopkinson Pressure Bars
09:41

Blast Quantification Using Hopkinson Pressure Bars

Published on: July 5, 2016

这就是哈布尔常数.

J P Huchra

    Science (New York, N.Y.)
    |April 17, 1992
    PubMed
    概括

    哈勃恒定测量宇宙的膨胀速度. 目前的测量有很大的差异,与宇宙学模型和理论产生不一致.

    科学领域:

    • 宇宙学的宇宙学是什么?
    • 天体物理学 天体物理学

    背景情况:

    • 哈勃常数 (H0) 量化了宇宙膨胀速度,对于确定宇宙规模和年龄至关重要.
    • 精确的H0测量对于验证宇宙学模型和理解宇宙进化至关重要.

    研究的目的:

    • 为了突出在确定哈勃常数方面持续存在的挑战和差异.
    • 讨论不同H0值对宇宙学理论的影响.

    主要方法:

    • 测量星系衰退速度和距离被用来确定H0.0.
    • 为精确测量银河系距离而开发新的技术正在进行中.

    主要成果:

    • 目前的H0测定显示了广泛的范围,几乎是2.0的因素.
    • 当地测量通常会产生更高的H0值,与一些理论预测相冲突.

    结论:

    • 持续的校准不确定性和系统错误阻碍了最终的H0值.
    • 当地和全球H0测量之间的差异对当前的宇宙学理解和结构形成和恒星进化理论构成重大挑战.

    更多相关视频

    Quantifying Microorganisms at Low Concentrations Using Digital Holographic Microscopy (DHM)
    07:27

    Quantifying Microorganisms at Low Concentrations Using Digital Holographic Microscopy (DHM)

    Published on: November 1, 2017

    A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference
    07:56

    A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference

    Published on: September 5, 2019

    相关实验视频

    Last Updated: Jul 8, 2026

    Blast Quantification Using Hopkinson Pressure Bars
    09:41

    Blast Quantification Using Hopkinson Pressure Bars

    Published on: July 5, 2016

    Quantifying Microorganisms at Low Concentrations Using Digital Holographic Microscopy (DHM)
    07:27

    Quantifying Microorganisms at Low Concentrations Using Digital Holographic Microscopy (DHM)

    Published on: November 1, 2017

    A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference
    07:56

    A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference

    Published on: September 5, 2019