There are different opinions of the dynamics of an air bubble entering a xylem conduit. In this paper, we present a thorough mechanical analysis and conclude that there are three types of cavitation caused by air seeding. After an air seed enters a conduit at high xylem pressure P'(1), along with the drop of the water potential, it will expand gradually to a long-shaped bubble and extend continually. This is the first type of air seeding, or the type of expanding gradually. When the xylem pressure is moderate, right after an air seed enters a conduit, it will expand first. Then, as soon as the pressure reaches a threshold the bubble will blow up to form a bubble in long shape, accompanied by acoustic (or ultra-acoustic) emission. It will extend further as xylem pressure decreases continually. This is the second type of air seeding, or the type of expanding-exploding, becoming a long-shaped bubble-lengthening by degrees. In the range of P'(1) ≤ - 3P(o) (P(o) is atmospheric pressure), soon after an air seed is sucked into a conduit it will explode immediately and the conduit will be full of the gas of the bubble instantly. This is the third type of air seeding, or the type of sudden exploding and filling conduit instantly. The third type is the frequent event in daily life of plant.
User participation in innovation is an effective way for companies to meet user needs and achieve value co-creation. The construction of online communities in the context of the mobile Internet provides a complete platform system for users to participate in innovation. The research on the impact is not enough. Based on the self-determination theory and inspired by the SO -R model, this paper takes the user experience value of the online community as the stimulus, and constructs a relationship model that influences the psychological needs of users and their willingness to participate in innovative behaviors.
Recently, three types of cavitation: (i) expanding gradually; (ii) expanding-exploding, becoming a long-shaped bubble-lengthening by degrees; (iii) suddenly exploding and fully filling the conduit instantly, were proposed. Directed by this theory, experiments were performed using light microscopy to study the natural drying processes of xylem sections of Platycladus orientalis (L.) Franco. Three different phenomena of gas filling process in conduits were captured by replaying recorded videos. The first phenomenon is that a bubble emerging in a conduit expands and elongates gradually to fill the conduit. The second phenomenon is that a bubble emerging in a conduit expands gradually, and then suddenly becomes long-shaped, and extends continuously. The third phenomenon is that a bubble instantly fully fills a conduit. This paper suggests in these experiments that after losing the bulk water of a section, as the water stress of that section became more severe, the water pressures of different conduits of the section were not necessarily the same, and as time went on, the water pressures decreased constantly. Considering some practical factors, the three phenomena captured in our experiment are explained by our theory.
Abstract-Customers for products and services is an important factor in restricting consumer purchase behavior, and developing and nurturing customer ability to predominate and control is a prerequisite for customers to buy the products, as well as capture points of corporate marketing points and resources to accessing core customer. Based on the theoretical derivation of the customer's ability to predominate and control, we analyze the nature of the customer's control, and define the concept of the customer ability to predominate and control, while describes its basic connotation and denotation scientifically, eventually forming the conceptual model of the customer's ability to predominate and control.
The ecological psychology holds that the human behavior is the result of the interaction between human and environment. And in a certain service context, the customer behavior is not only affected by the physical environment, but also by human which is an important factor. Based on the theory of ecological psychology and service environment, the paper redefines the concept of service environment and analyzes its connotation. On this basis, the paper also discusses the measurement dimensions of service environment from two aspects of physical environment and social environment.
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