Liquid phase method is the most widely used method among many methods for synthesizing nano tungsten trioxide. Its advantage is that the nano structured WO3 particles are fine and evenly distributed, the content of the chemical components can be precisely controlled, the morphology of the nanostructured WO3 can be controlled by adjusting the morphology control agent, the synthetic process is simple, economical and good to mass production. There are four main methods including hydrothermal synthesis, sol-gel method, precipitation method and microemulsion method.

For GTAW welding, tungsten electrodes are chosen for its good properties of low electric discharged powder, good welding arc, high temperature resistance, sharpening machinability and low radiation. There are many grades are suitable for the welding, difficult welding objectives and conditions, different grade is applied.

This article will discuss the gas sensitivity of nano plate shaped tungsten trioxide gas sensor at different concentration of ethanol gas, acetone gas, ammonia gas and formaldehyde gas in terms of temperature-sensitivity. As semiconductor material with good sensitivity to various toxic gases, nanostructured tungsten trioxide can effectively improve the sensitivity and response speed of gas sensors. The gas sensor using nanostructured tungsten trioxide as gas sensitive material can be done to make lower thickness detection of target gas, which can greatly decrease the harm of noxious gas to human health. Therefore, the research of nanostructured WO3 is good to make full use of its good semiconductor property, improve its value in the gas sensing field, and provide better semiconductor material.

There are many preparation methods of tungsten disulfide nanoparticles. Tungsten disulfide is  two-dimensional material with layered structure and has excellent semiconductivity and diamagnetism. It is insoluble in acid, alkali and alcohol, and has certain reducibility, which can react with aqua regia, nitric acid and hot concentrated sulfuric acid, and is able to be oxidized to WO3 in air and oxygen atmosphere.