RESUMO
Computer aided design and simulation of complex silicon microsystems oriented for environment monitoring requires efficient and accurate models of ion selective sensors, compatible with the existing behavioural simulators. This paper concerns sensors based on the back-side contact Ion Sensitive Field Effect Transistors (ISFETs). The ISFETs with silicon nitride gate are sensitive to hydrogen ion concentration. When the transistor gate is additionally covered with a special ion selective membrane, selectivity to other than hydrogen ions can be achieved. Such sensors are especially suitable for flow analysis of solutions containing various ions. The problem of ion selective sensor modelling is illustrated here on a practical example of an ammonium sensitive membrane. The membrane is investigated in the presence of some interfering ions and appropriate selectivity coefficients are determined. Then, the model of the whole sensor is created and used in subsequent electrical simulations. Providing that appropriate selectivity coefficients are known, the proposed model is applicable for any membrane, and can be straightforwardly implemented for behavioural simulation of water monitoring microsystems. The model has been already applied in a real on-line water pollution monitoring system for detection of various contaminants.
Assuntos
Eliminação de Resíduos Líquidos/métodos , Poluentes da Água/análise , Simulação por Computador , Hidrogênio , Eletrodos Seletivos de Íons , Íons , Modelos Estatísticos , Modelos Teóricos , Compostos de Amônio Quaternário/química , Processamento de Sinais Assistido por Computador , Compostos de Silício/química , Água/análise , Poluição da ÁguaRESUMO
This paper presents an approach of the two-dimensional image processing application in recognition of amyloid plaque in microscope images of the brain tissues. The authors propose to create universal amyloid plaque computer pattern and special multivariate image segmentation techniques based on collected images and statistical information. This recognition image procedure is divided into 3-dimensional statistical colour and morphological shape identifications. The developed computer system will collect and store image data and exchange them by network with other collaborated systems.
