The efficacy of herbicides is influenced by many factors and needs to be considered in all aspects of the application process. Herbicide is an important means to effectively control weeds, but the use of herbicides is not a simple spray to obtain good control or control effects, which is also affected by many other factors.
Compared with insecticides and fungicides, the use of herbicides is more complicated, and its effectiveness is often influenced by many factors, as follows:
1 temperature and humidity issues
The high temperature and temperature are beneficial to the herbicide being absorbed by the weeds, and the effect is good. But not the higher the temperature, the better, the temperature is too high, the sprayed mist is quickly evaporated, especially for some volatile herbicides and photolysis-decomposing herbicides, which will reduce the herbicidal effect, such as 2,4-D Fluorine, Heda Zhuang, Methoc tetrachloride, etc., will also cause phytotoxicity due to volatilization and drift to sensitive crops around. When the temperature is too low, the grass is used, and the plant can not be degraded in time, which is prone to phytotoxicity. The correct application should be: high temperature season, sunny and windless before 11 am and after 4 pm; low temperature season should be between 10 am and 3 pm.
2 soil water content problem
The soil has high humidity and high water content, which is beneficial to the growth of crops and weeds. At this time, the herbicide can enhance the absorption capacity of weeds, accelerate the conduction and transportation in the body, and make the herbicides play a role in killing weeds; Drought, less rain, slow growth of crops and weeds, and crops are weaker, so resistance is poor, and weeds will make stems and leaves form better cuticles and fruit micelles, stems and leaves become dry, The liquid medicine is difficult to be absorbed and transmitted by the weeds. Therefore, the herbicide should be appropriately increased in the dry weather, and the amount of water spray should be increased accordingly.
3 use the issue of the period
Generally, herbicides can be applied before and after sowing and in the late stage of seedlings. However, different herbicides have the best application period of application, and the seedlings (buds) are applied before or after sowing. The application should be used in the post-emergence; if the post-emergence weeding requirements are to master the weeds 2~3 leaf stage, if the spraying has exceeded the age, the weed resistance is strong and the effect is poor. Therefore, we must correctly master the appropriate application.
4 spray quality problems
When the spray is not evenly mixed, if the upper and lower layers of the whole barrel are inconsistent, there will be some weeding effect after spraying, and some will have no effect. There will also be insufficient water spray and too low or too high a dose, which will affect the herbicidal effect and even cause phytotoxicity.
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Specification
Apparent density: 2.10~2.30g/cm3
Tensile strength: 15.0Mpa
Ultimate elongation: 150%
PTFE is principally used as a gasket material because of it's capability to remain unaffected by the majority of chemicals used in industry. It is also classified, in most cases, as a food grade material, making it acceptable to both medical and food production industries. There are three basic types of PTFE Gasket materials. Virgin PTFE , filled PTFE and expanded PTFE .Features
Acid and alkali resistant
Chemical resistant
Has minimum friction coefficient of all know pure material
Non-viscous, no aging
Now molds can be made according to customers requirements.
Virgin PTFE is by far the least expensive of the three varieties, and is used in most general applications. Filled PTFE is a gasket material with a virgin PTFE base to which a substance is added during manufacture to improve the sealing characteristics of PTFE . This "filler" usually is glass or graphite particles although ceramics has sometimes been used. The resulting gasket material is strong, yet highly compressible with very good, though not universal, chemical resistance.
Expanded PTFE is virgin PTFE to which a stress resistance has been added by means of molecular rearrangement during manufacture. This process ensures that the molecular chains from which the PTFE is constructed, do not arrange themselves into set patterns. This means that expanded PTFE possesses no structural weakness (grain) and expands and contracts equally in all directions. Because no additives are required, expanded PTFE also possesses the unique chemical resistance of virgin PTFE.
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