The chemical oxygen demand(COD) in Seawater is an organic contaminant synthetical indicator and one of the most
important ocean environment monitoring items. At present, the marine pollution in China is serious day by day, but the
traditional COD measurement method can not meet demand. It is essential to research the real-time monitoring system
with no time delay, no reagent application and no secondary pollution. The basic principles of analytical techniques and
a real-time monitoring system for the measurement of seawater COD were described in this paper. The basic
principles were based on the ultraviolet absorbency degree analytical method. The correlation between ultraviolet
absorbency degree and COD in seawater was studied in this paper. The result showed that under certain condition, it
could calculate COD value from ultraviolet absorbency degree. A novel seawater COD sensor was designed in this
paper, and it could circularly lead in the seawater cleaning out the contamination.
This paper holds landslide monitoring system based on fiber optic sensors network. When
structural distortion is occurred in landslide area, it will affect the change of fiber bragg grating
space, and brings on the offset of the fiber bragg wavelength.The information of the destroyed
point is obtained with the demodulated system.It applies annular distribution to mountain body,
and establishs homologous fiber optic sensor network which collect all the information to the
home site. This technique can provide the managers, policy-makers and experts the real time
change of the parameters of the disaster, and the feedback can be given to monitoring station
through the monitoring network. Therefore, it will be an important technical support for real time
dynamic monitoring.
This paper uses a contact mechanics and radial crushing strength to analyze the force properties of photonic crystal fiber which is placed in the V-groove. In this paper, we calculate the stress distribution of the fiber in the V-groove under two ultimate conditions. The first one is supposed that fiber is a solid cylinder which is fabricated by isotropy material. The second one is supposed that fiber is a hollow cylinder. It is calculated that the maximal stress of the fiber is the tension. This stress is near the outer air holes which are parallel to the contact surface. Then we use finite-element (FE)approach to testify the result and calculate the maximal stress the photonic crystal fiber could hold. Finally, we present the stress distribution and the strain of the fiber.
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