For a complex and diverse subject such as the soil, where should we start to understand the soil? Or we should start from the objective phenomenon of the universal soil, use the soil tester to measure the internal structure and composition of the soil, and analyze the most basic internal connection of this phenomenon, so as to summarize the concept of soil.
Soil can grow plants. This is a simple phenomenon that exists in nature or under artificial conditions. It is also a common objective fact. When the soil is initially formed, the hydrated soil is earlier than the land soil. The period when plants lived in large numbers on the land and clustered with the ground began in the middle of the Paleozoic era, about 400 million years ago. When a plant is born on the surface of the original young soil, in addition to other natural conditions, the plant must obtain material and energy from the soil in order to survive and develop. When the primitive juvenile soil has this basic property of supplying the plants with the necessary energy and energy, it shows the most essential characteristics of the soil, becoming soil and distinguishing it from other natural substances in the natural world and appearing on the surface of the earth. Factors such as climate, rock, and topography have long existed objectively before the formation of soil, and the appearance of plants and soil on the earth's surface both take the existence of each other as their own survival (for plants) and formation (for In terms of soil, and under the influence of various other natural factors, the soil and plants are continuously developed and evolved according to their own laws. Therefore, the concept of soil outlined from the point where soil can grow plants can deepen the understanding of soil.
From the above, it can be considered that the basic characteristics of soil-grown plants, in addition to the role of the atmosphere, can be understood as the processes by which the soil material and energy are absorbed and transformed into plant bodies through the use of plant roots. That is, soil-grown plants are soil-intrinsic. The external manifestation of matter and energy through plant transformation, all surface materials that have this form of material and energy biotransformation are called soil. The ecological relativity of soil fertility to be clarified in this paper is based on this concept of soil.
There are also some scholars' ideas about the soil concept. For example, NC Braddy (1974) described two different views of the soil as the natural body and the soil as the plant's habitat, and considered that there must be a general soil concept, and at the same time ask “what is the soil? "This general concept should be summarized in terms of engineers, homeowners, and farmers. It seems that this idea of ​​NcBrady is based on the facts of the country where he is based. In general, it is difficult to put forward the necessary guidelines for this soil concept.
There are many grades of PVC. The viscosity or K value commonly used in the industry indicates the average molecular weight (or average degree of polymerization) of PVC, that is, the length of the PVC molecular chain, which determines the grade of the resin and the corresponding processing parameters. The molecular weight of the resin is related to the physical and mechanical properties of the product.
PVC Resin is a kind of non-crystalline linear polymer compound. The larger the relative molecular mass, the higher the viscosity, the higher the molecular weight, and the higher the tensile strength, impact strength, and elastic modulus of the product, but the flow of the resin melt Decline in sex and plasticity. The viscosity number is usually used to indicate the molecular weight of the polymer, and the polymer model is divided
PVC used to be the largest general-purpose plastic in the world, and it is widely used. It is widely used in construction materials, industrial products, daily necessities, floor leather, floor tiles, artificial leather, pipes, wires and cables, packaging films, bottles, foam materials, sealing materials, fibers, etc
SG3 (K-70, S1300): mostly used for soft products, hoses, wires and cables, films, shoe materials, toys, auto parts etc.
PVC RESIN SG3 has high purity, less fish eyes, easy to blister, high temperature resistance, insulation, soft product texture, etc. It is mainly used to produce soft products such as wires and cables, agricultural films, conveyor belts, and daily plastic products.
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