The scientific method of soil moisture can generally be expressed by the soil moisture content, soil moisture content, etc. For different soil types in China, the soil moisture content is greatly different, and the soil moisture recorder can be used for different regions. Moisture is measured and this difference pays attention to the soil texture and soil structure.
The more viscous and well-structured the soil, the greater the force of holding water, ie, the more water is stored, the higher the value of the water constant; on the contrary, the texture is worse and the structure is worse. The less water, the lower the moisture constant. For example, in the moisture absorption coefficient (percentage of soil moisture when water has reached the maximum volume of water with respect to Nirvana saturation), the soil moisture content is 0.5% for the northeast, 9% for the low-lying middle soil, and the Yellow River. The amount of cement on both sides of the Yellow River irrigation area is 15%. However, the soil water content in the withering coefficient is 3% in fine sandy soil, 10% in middle loam soil, and 17% in clay soil in the same region.
The soil moisture that can be easily used by crops is between the field water holding capacity and the withering coefficient, which is generally å¨% of the total soil water storage capacity. It is the most suitable soil moisture content for crops. However, with different soil texture, the withering coefficient is different. On the contrary, the same soil texture, planting different crops, the withering coefficient is also different. As for the floodplain in the alluvial plain of Northeast China, the effect of soil texture on the withering coefficient is significant. Different crops also have significant differences in soil moisture requirements. For example, in the Beixinxiang area, in the slightly alkaline sandy loam soil, wheat can emerge at a soil moisture content of 7% (above the dry earth weight) or more, and when it grows at 10%, the emergence of wheat is good. However, the cotton can develop at more than 10%. 15 Only when the percentage was good.
Different soils have different effective water content. The more viscous the soil, the larger the withering coefficient and the more effective water content. In addition to affecting the withering coefficient of crops, soil texture also affects field water holding capacity and effective water content.
The amount of soil moisture does not serve as a basis for artificial filling. For example, a soil moisture content of 3% to 5% can meet the water demand of crops in sandy soils, and irrigation may not be considered. In silty sand soil, the water content is lower than the wilt coefficient, and crop growth has been affected. inhibition. It can be seen that the soil texture must be considered when artificial irrigation and irrigation are applied.
Cnc Turning is namely Lathe machining, Lathe machining is a portion of mechanical processing.
Lathe machining is always a process that turning tools doing turning machining to a rotary workpiece. On CNC lathes, the operators or the engineers also can use drills, reamers, screw taps, threading dies and knurling tools to make relative machining work. CNC Turning is usually applied to machining shafts, plates, bushings and all other workpieces which have rotary surfaces, it is a very widely application in practical mechanical manufacturing.
CNC turning can be divided into rough turning and finish turning, rough turning is for the purpose of machining with big cutting depth and big feed rate, to improve the machining efficiency. However, the precision of rough turning can only be grade IT11, the surface finish can only be Ra 20-10um. On the contrary, semi-finish machining and finish machining usually can only apply high speed but small feeding rate and cutting depth. In this condition, the machining accuracy can be up to grade IT10-7, the roughness can be Ra10-0.6um.
CNC Turning
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