The researchers use a combination of microscopy and spectroscopy to examine how that light is reflected .
研究人员用一种结合显微镜检查和光谱学的方法来检测反射光。
Several technical problems still needed to be resolved before a full spectroscopy system could be built .
在一个纯光谱学系统能够被建立起来以前，一直以来存在的一些技术问题需要被解决。
The scientists combined this with another technique called near-infrared spectroscopy , which can be used to monitor changes in blood flow in the brain .
科学家将这个和另一种可以监视大脑中的血液流通的叫做近红外线光谱学的的技术联系起来。
But technology is the basis of the explosive - detection business and it usually works either by examining the density of material using x-rays or by using spectroscopy to detect the mass and mobility of molecules .
In the 19th century , photography and spectroscopy - the study of the wavelengths of light that objects emit - made it possible to investigate the compositions and motions of stars from afar , leading to the development of astrophysics .
