通用信息
在分析技术中,很难找到像利用电磁波与物质作用原理那么广的技术,利用电磁波与物质作用的优点在于可以实现连续不间断测量,不与物料直接接触以及非破坏性的检测,所以广泛用于产品测量分析及质量控制工艺中。
名词释义
- Spectrum: Show 光谱Spectrum: Close
Electromagnetic radiation is in general a mixture of many small packets of energy. Each packet, also called photon, possesses a certain amount of energy. Each photon behaves like a wave with a definite frequency and wavelength. If the radiation is visible light, the wavelength corresponds to a colour: the wavelengths of 444, 555, and 666 nanometers are blue, green, and red light, respectively. White light contains all colours.
A spectrum is a kind of representation that shows how much of each wavelength is present in a given field of electromagnetic radation. The solar spectrum is an important example. It contains large amounts of visible light with an emission maximum around 500 nanometers. However, it also contains considerable amounts of ultraviolet and infrared radiation.
- Wavelength: Show波长Wavelength: Close
Electromagnetic radiation is created by the propagation of two coupled oscillating fields, an electric and a magnetic field. The wavelength of a packet of radiation is the distance between two maxima (or minima) of that oscillation. It can be converted into frequency or energy of the radiation. It is usually measured in meters or a derived unit such as nanometers. Visible light was wavelengths between 400 and 700 nanometers.
- Absorption: Show吸光度Absorption: Close
When light (electromagnetic radation) encounters matter, some fraction of that light can be absorbed by the matter. Each kind of matter (atoms, molecules, crystals, plasmas...) absorb a certain set of wavelengths depending on, for instance, the distribution of electrons or the mobility of particles in the material. When a known spectrum of radiation is sent into a sample, then the spectrum that is detected behind the sample contains information about the composition about the sample. With good calibration, it is possible to obtain very precise quantitative results.
- Transmission: Show透射Transmission: Close
Transmission is the process to make light (electromagnetic radiation) pass through a sample. Commonly, the original spectrum of radiation is compared to the transmitted spectrum in order to identify absorption at certain wavelengths. That absorption pattern contains information about the composition of the sample. Additional reflection or scattering processes need to be considered and can be taken into account by adequate spectral calibration. If the sample is so dense that it is opaque, transmission measurements are not possible. Reflection measurements are an alternative for such cases.
- Reflection: Show反射Reflection: Close
Reflection occurs when light (electromagnetic radiation) hits a sample and is directed back instead of entering the sample. Reflection can be diffuse (evenly distributed in all directions, think of sand) or specular (angle of reflection equals angle of incidence). Most common, however, are intermediate forms - think of the vague reflection of the sun on an otherwise matte surface). Reflection depends on wavelength, and in general certain wavelengths (not necessarily visible) are still capable of penetrating the probe and are subject to absorption. Therefore, reflection measurements can also be used to investigate the composition of a sample.
许多物料的吸光特性可以通过选择合适的光谱和波长的仪器来检测
PIER-ELECTRONIC GmbH的光度仪可以广泛应用于许多领域中,并且能适用不同的环境条件。用于仪器中的透光元件一般为tempax, quarz 玻璃或者sapphire材料,这些材料具有很高的机械抗性以及低维护性。对于发生在反应容器之内的测量,只需要借助光纤即可实现。
三款探头的测量原理
透射式光度仪
(types TMK-550 or 480-CT)
透射式光度仪一般被选择用于测量液体和气体物料。 光束通过一个特定厚度的池体,该池体中填充了待测液体或气体,透过该池体后的光记录了待测物料的组成信息。并且如果是生产过程中温度变化很大或者压力变化大的物料,则可以选择各种补偿方法给予结果进行补偿,以消除这些因素对测量结果的干扰。
该款仪器的优点:针对特殊环境条件,能源利用的高效性
反射式光度仪
(types RMK-10 or RMK-24)
反射式光度仪一般用于检测粉末状和其他固态物料,比如纸张,薄金属板,颗粒物或者胶状物料。物料的原子或者分子对红外光进行折射和反射,折射和反射过来的光就记录了物料的组成信息。
该款仪器的优点:无需制备样品却能记录样品的理化信息
透反射一体机
(type RMK-9T) 此款仪器结合透射和反射原理对特殊的胶片湿度进行检测。红外光穿透胶片,然后底部镜片对此光进行反射,再次穿透胶片,最后回到传感器上。 优点:通过增加光程提高其精度。