相关实验视频
Updated: Jun 26, 2026

08:31
Three-dimensional Optical-resolution Photoacoustic Microscopy
Published on: May 4, 2011
概括
科学家们在材料研究协会 (MRS) 会议上探索了各种材料科学主题. 关键的发现包括新的光到声音设备,量子点研究和混合材料.
科学领域:
- 材料科学 材料科学 材料科学
- 凝聚物质物理学 凝聚物质物理学
- 化学 化学 化学
背景情况:
- 材料研究协会 (MRS) 秋季会议召开专家会议,讨论材料方面的进展.
- 范围从原子层次的现象到宏观的材料特性.
研究的目的:
- 介绍和讨论材料科学的各个领域的尖端研究.
- 促进物理学家,化学家和材料科学家之间的合作和知识交流.
主要方法:
- 展示了4000多篇研究论文和海报.
- 讨论材料研究中的实验和理论发现.
主要成果:
- 展示了能够直接将光转换为声音的新型设备.
- 引入了用于研究量子点的新方法.
- 介绍了有机-无机混合材料的合成和表征方面的进展.
结论:
- 在MRS会议上强调了在多个尺度上理解和操纵材料方面取得的重大进展.
- 像光声传导和纳米材料表征等新兴领域显示出很大的前景.
相关概念视频
Sound Intensity
The loudness of a sound source is related to how energetically the source is vibrating, consequently making the molecules of the propagation medium vibrate. To measure the loudness of a source, the physical quantity of interest is the intensity. This is defined as the energy emitted per unit of time per unit of area perpendicular to the sound wave's propagation direction. Since the total energy is greater if the source vibrates for a longer duration and over a larger area, dividing the emitted...
Sound Intensity Level
Humans perceive sound by hearing. The human ear helps sound waves reach the brain, which then interprets the waves and creates the perception of hearing. The loudness of the environment in which a person is located determines whether they can distinguish between different sound sources.
The human ear can perceive an extensive range of sound intensity, necessitating the use of the logarithmic scale to define a physical quantity—the intensity level. It is a ratio of two intensities and hence a...
The human ear can perceive an extensive range of sound intensity, necessitating the use of the logarithmic scale to define a physical quantity—the intensity level. It is a ratio of two intensities and hence a...
Sound as Pressure Waves
Sound waves, which are longitudinal waves, can be modeled as the displacement amplitude varying as a function of the spatial and temporal coordinates. As a column of the medium is displaced, its successive columns are also displaced. As the successive displacements differ relatively, a pressure difference with the surrounding pressure is created. The gauge pressure varies across the medium.
The pressure fluctuation depends on the difference in displacements between the successive points in the...
The pressure fluctuation depends on the difference in displacements between the successive points in the...
Intensity and Pressure of Sound Waves
The intensity of sound waves can be related to displacement and pressure amplitudes by using their wave expressions and the definition of intensity. The critical step to achieve this is to write the power delivered by the particles on the wave as the product of force and velocity and simplify the force per unit area as the pressure. The velocity of the medium's particles can be derived from the displacement.
Unlike the time average of a sinusoidal term, which is zero since it is positive and...
Unlike the time average of a sinusoidal term, which is zero since it is positive and...
Echo
The human ear cannot distinguish between two sources of sound if they happen to reach within a specific time interval, typically 0.1 seconds apart. More than this, and they are perceived as separate sources.
Imagine the sound is reflected back to the ears. Assuming that the source is very close to the human, the difference between hearing the two sounds—the emitted sound and the reflected sound—may be more than the minimum time for perceiving distinct sounds. If this is the case, then the...
Imagine the sound is reflected back to the ears. Assuming that the source is very close to the human, the difference between hearing the two sounds—the emitted sound and the reflected sound—may be more than the minimum time for perceiving distinct sounds. If this is the case, then the...
Perceiving Loudness, Pitch, and Location
The human brain perceives pitch through two primary mechanisms reflected in place theory and frequency theory. Each mechanism describes how sound waves are interpreted as specific pitches by the brain, offering insights into the intricate processes of auditory perception.
Place theory, or place coding, suggests that different pitches are heard because various sound waves activate specific locations along the cochlea's basilar membrane. The brain determines the pitch of a sound by identifying...
Place theory, or place coding, suggests that different pitches are heard because various sound waves activate specific locations along the cochlea's basilar membrane. The brain determines the pitch of a sound by identifying...

