of the composition and structure of the substance are called the
ion-beam analysis, which can in turn be roughly divided,
according to the difference in characteristics, into proton-
excited X-ray fluorescent analysis, nuclear reaction analysis,
back-scatter analysis, channel technique, and accelerator mass-
spectro-graphic analysis.
Proton-excited X-ray fluorescent analysis:
High-speed
protons, when bombarding the sample, ionize the electrons in
the inner layer of the atoms of the various elements and thus
produce the holes. When the electrons of the outer layer
migrate into those holes, the atoms of the elements are de-
excited and emit characteristic X-rays. To detect their
energy and intensity whith silicon (lithium) X-ray detector
can tell the types of elements and their content in the sample.
This method is chiefly used in biology, medical science,
vironmental science and material science. For instance, this
analytic method has been applied to analyze such famous liquors
as Wuliangye, Jiannanchun, Lizhou Tequ and Guizhou Maotai; the
result is that the tonic rare elements contained in the above-
en-
mentioned liquors are much more than the contents in common
liquors. And the anlaysis on domestic and foreign beers in-
dicates that the China-made beer has a large variety of
nutritious elements necessary for human body and the content
thereof is appropriate. On the other hand, the presence
of such poisonous elements as lead, arsenic, mercury and cadmium
is several times lower or an order-of-magnitude lower than the
P. 4
The Translation Division of Tai Dao Publishing LIC