| The past hydrogen sensors belongs to semiconductor sensors. When they worked, it needs the electric power in addition, and they are easy to be interfered by electromagnetic waves. It also have complex configuration. The optical fiber sensors can not be rot easily and be interfered by electromagnetic. They have high sensitivity and are suitable to measure in long instance. So, they have the stronger affinity in inspecting the nuke in the storage. Along with the development of the correlate countries' technology in nuke and the request of the nuclear forbidden, the estate-inspection and diagnose of the ordnance in storage have been recognized by the governments and the scientific community. Our country quite need to investigate and develop high sensitivity optical fiber hydrogen sensors. This important basic job of the research object is the embed research in the hydrogen characterstics of the films and its mechanism.This problem have three key aspect: the first is how to choose the hydrogen films, the second is how to make the films, the last is how to check the films. Ultra micron SnO2 and WO3 attribute to N type semiconductor substance, the formers have the electricity in surface interspaces former, the grain boundary interface potential barrier, the absorption gas producing energy level former and AET former. It can use spatter, coating by vaporization, and CVD to make the substance to films. It is the most widely used hydrogen sensitivity material.This time, the way is the PVD and the sol-gel. PVD means using some physical process, i.e., the vapor of substance or the spatter of the atoms in surface when they are bombarded by ion beam, realize the process of the atoms transfer from matter to the films. The magnetism controlling spatter is using the ion with charge speed in the electric field to collided with the atom in the target surface and the latter are spattered. These atoms have certain kinetic energy, and they can send out to the underlay along a certain direction. Then, they will become an aggradation on the underlay. The sol-gel is a very important method in the films madding. The method is using the metal alkoxide as the material, and it will be dissolved by organic solvent. Then, it will be violently and quickly milled into the sol, and sol will be dried in low temperature to become the gel. So, we will dry it in a certain temperature and humidity to made it into a film. Then, the gel-film are baked over a slow fire in high temperature to be a kind of oxidemicroporous membrane with a certain cultivate characteristics.The sensors reviewed in this report have been categorized into four general groups: (1) chromatography and spectrometry; (2) electrochemical sensors; (3) mass sensors; and (4) optical sensors. The categorization of these sensors is based primarily on the principal physics and operating mechanisms of the sensor. For example, chromatog-aphy relies on separation of complex mixtures by percolation through a selectively adsorbing medium, with subsequent detection of compounds of interest. Electro-chemical sensors, for the purpose of this report, include sensors that detect signal changes (e.g., resistance) caused by an electrical current being passed through electrodes that interact with chemicals. Mass sensors rely on disturbances and changes to the mass of the surface of the sensor during interaction with chemicals. Optical sensors detect changes in visible light or other electromagnetic waves during interactions with chemicals.The article have reviewed the method of making the films and how to monitor the function of the films, and founded a set of the experiment plan. After the research of the experiment, we made out the type of the WOa hydrogen films. We monitored the optical performance of the films, and get the satisfied result. It has made a very strongly base for next research as the configuration characteristic of the films, the hydrogen sensitivity mechanism, the more exactitude and easier method of monitor, the development of optical fiber sensor, and so on.
|
PDF Full Text Request