Study on the pure DC transmission scheme for China's future power transmission from the West to the East
In the year after 2015, China's national power grid interconnection will have been completed. Most likely, there will be four synchronous power systems, that is, big East China power grids, central China power grids, South China power grids and Northwest China power grids. For the long distance (more than 1000 km) bulk power (more than 50 GW) transmission from the West to the East, if the pure DC transmission scheme is adopted, there will be more and more HVDC links feeding power to different points in the same synchronous AC network. An important issue arising in such a situation is the influence of the multiinfeed HVDC links on the security of the AC systems. This paper analyzes the transient stability of each system under various AC and DC disturbances. The recovery characteristics of the multiinfeed HVDC links are also investigated. The results show that pure DC power transmission from the West to the East of China is technically feasible
RAISING STABILITY LIMITS IN THE NORDIC POWER TRANSMISSION SYSTEM
The aim of this paper is to present power system stability analyses, which are part of ongoing efforts to raise transmission capabilities in the Nordic power transmission system. The studies focus on the assessment of angle stability limits and the impact of power system stabi- lisers (PSSs). The paper describes applications and testing of prototype devices for on-line power system monitoring (the Voltage Instability Predictor, VIP and Phasor Meas- urement Units, PMUs). Utilisation of phasor measurements as input to power system stabilisers is analysed. Selected results from measurements and computer analyses, using a complete Nordic transmission system model, are shown to illustrate the main benefits from the study. The results indicate that it is possible to raise exist- ing stability limits on important transmission corridors through improved control and better understanding and monitoring of system stability properties. In combination with other ongoing efforts this will enable the system op- erator to raise present operating limits.
Role of computer technology in medical illustration.
OBJECTIVE
Recent improvements of computer technology have resulted in a new approach to medical illustration and the scientific research process. The purpose of this manuscript is to define the current state of the art and to review paths of progress.


CONCLUSION
Using examples, we compared the process of time-intensive hand-rendered art with current art created using new computer technology. Specific emphasis was made on the newest technologies and how high-quality lower cost medical art can now be created. These newly available tools and illustration methods have resulted in a new approach to research, creation, and reproduction of medical art.