Search

The operation of pipelines has been affected by the corrosion caused by water deposited in some low sections of liquid products and natural gas pipeline. Flushing out the deposited water by flowing diesel has become a popular method. This research focused on a local water-diesel flow system with low Uos, in which the flow pattern, velocity and shear stress were analyzed through 2D simulation conducted by FLUENT software based on the grid independent strategy; meanwhile the simulations were verified by comparison with the published data. Under the shear from flowing diesel with laminar flow, the flow pattern was found mainly as smooth and wavy stratified flow. The velocity of diesel phase becomes similar-parabolic distribution with an offset upwards in the radical direction, while there are reflux and eddy inside the residual water. Because of the presence of residual water, the shear stress of the walls become negative, and it increases along the two walls to the interface radically and increases to the maximum on the interface. The average velocity of residual water was found to increase linearly with the superficial velocity of oil flow.

The skew diffusion process is a special diffusion process. The stochastic differential equation expression of such a special process contains the symmetric local time.Due to its special property, this model is widely used in physics and biology. Starting from skew Brownian motion,this work summaries its two constructions: discrete approximation and jointly probability distribution. Based on the skew Brownian motion, we provide the definitions for the skew Ornstein-Uhlenbeck (OU) process and skew branching process, and derive their properties: transition density, first hitting time, etc.We also introduce some applications under the skew diffusion processes.

Small and Medium-sized Enterprises (SMEs) in the process of wage entry, calculation, the total number are needed to be done manually in the past, the data volume is quite large, processing speed is low, and it is easy to make error, which is resulting in low efficiency. The main purpose of writing this paper is to present the basis of salary management system, establish a scientific database, the computer payroll system, using the computer instead of a lot of past manual work in order to reduce duplication of staff labor, it will improve working efficiency.This system combines the actual needs of SMEs, through in-depth study and practice of the C/S mode, PowerBuilder10.0 development tools, databases and SQL language, Completed a payroll system needs analysis, database design, application design and development work. Wages, departments, units and personnel database file are included in this system, and have data management, department management, personnel management and other functions, through the control and management of the database query, add, delete, modify, and other functions can be realized. This system is reasonable design, a more complete function, stable operation has been tested to meet the basic needs of the work.

Voltage collapse dynamics has been modeled by the movement of the system state along a particular trajectory at a saddle node bifurcation. In this paper, appling this voltage collapse model to a simple 3-bus power system model, we will establish the dynamic behaviors of fractional-order Lu et al system based on the stability theory of fractional-order systems, some sufficient conditions are given. Numerical simulations are shown to verify the result and the theoretical analysis.

Profibus, CAN bus are two kinds of industrial field bus, which account for 30% in the field of industrial control. At present fieldbus conversion products in the market only achieves the conversion between RS232 and RS485, which can no longer meet the needs of users. However, by comparing the OSI reference model Profibus, CAN communication model structure are found to be streamlined by the OSI model, and they are only three layers, which makes it possible to interconnect with each other. Aiming at solve the problem mentioned above that the two kinds buses cannot be interconnected, Profibus and CAN bus protocol conversion interface has been designed to achieve Profibus and CAN bus protocol conversion. As the limits of microcontroller frequency, it is difficult to achieve two kinds of bus communication speed requirements. Therefore, a microcontroller + protocol chip designing method is proposed: protocol communication speed of microcontroller is low; microcontroller chip can make up for this shortcoming, which effectively alleviate the pressure on the microcontroller. When designing Profibus and CAN bus protocol conversion interface, using microcontroller AT89C52, protocol chips were selected by Siemens SPC3 and Philips SJA1000, and accompanied by a detailed software developing plan.