Flood Routing Models in Confluent and Dividing Channels

By introducing a water depth connecting formula, the hydraulic equations in the dividing channel system were coupled and the relation of discharge distribution between the branches of the dividing channels can be yielded. In this manner, a numerical model for the confluent channels was established to study the variation of backwater effects with the parameters in the channel junction. The meeting of flood peaks in the mainstream and tributary can be analyzed with this model. The flood peak meeting is found to be a major factor for the extremely high water level in the mainstream during the 1998 Yangtze River flood. Subsequently the variations of discharge distribution and water level with channel parameters between each branch in this system were studied as well. As a result, flood evolution caused by Jingjiang River shortcut and sediment deposition in the entrance of dividing channels of the Yangtze River may be qualitatively elucidated. It is suggested to be an effective measure for flood mitigation to enhance regulation capability of reservoirs available upstream of the tributaries and harness branch entrance channels.

a higher-order duration calculus and its completeness

National Natural Science Foundation of China; Public Administration and Civil Service Bureau of Macau SAR; Companhia de Telecomunicacoes de Macau S.A.R.L.; Macau SAR Government Tourist Office

Refractive index and thickness analysis of natural silicon dioxide film growing on silicon with variable-angle spectroscopic ellipsometry

The refractive index and thickness of SiO2 thin films naturally grown on Si substrates were determined simultaneously within the wavelength range of 220-1100 nm with variable-angle spectroscopic ellipsometry. Different angles of incidence and wavelength ranges were chosen to enhance the analysis sensitivity for more accurate results. Several optical models describing the practical SiO2-Si system were investigated, and best results were obtained with the optical model, including an interface layer between SiO2 and Si, which proved the existence of the interface layer in this work as described in other publications.

工作群体有效性评价及群体工作设计

This thesis study the problem of work group effectiveness and group job design according to extensive literature investigation and the analysis of realistic background. The whole research consists of four parts: (1) The evaluation of work group effectiveness, the aim is to search to criteria that can describe and analysis work group, and explore the cognitive dimensions of effectiveness of Chinese subjects; (2) The study on the relationship between group job characteristic and effectiveness, the aim is to find the general correlation between work group characteristic and effectiveness, and try to search the most important core variable; (3) The study on the preference for the way of group work; (4) The study of the relationship between group composition and group effectiveness, try to examine how different approaches of personnel selection influence work results. The results indicate: (1) The evaluation of group effectiveness mainly consists of two dimensions: performance and the employee's attitude and feelings toward the group, so we can use these two dimensions and corresponding criteria as the standard of effectiveness evaluation. (2) According to the analysis of related literature, we can determine work group characteristic from five aspects: job design, the interdependence among members, group composition, organizational background, group process. (3) Experimental study find that different group job characteristics have different relationship models with effectiveness criteria. Job design, the interdependence among group members, group composition have significant correlation relationships with two kinds of effectiveness criteria; organizational background mainly has relationships with satisfaction criteria; group process mainly has relationships with performance criteria. (4) The choice for people to select the way of group work has the consistency, that is people prefer to "Self--managed work groups"; but different groups have the difference, the main group dimension is the difference between group members and group leaders. (5) Work groups which were composed accordingly to interpersonal attraction have higher levels of communication, coordination, group cohesion and job satisfaction than ability--based groups based. But the performance evaluation under these two conditions has no difference. The thesis analysis and discuss the research results, also point out several questions that needed to be explored further and the possible research directions in the future. This study has some reference value in group--level performance appraisal and reward design, the content and method of group--level job design, and personnel selection of group, etc.