Jiri Cengery

Non-invasive monitoring of the human blood pressure

The paper deals with continuous blood pressure measurement. In the intensive care, there is a need to monitor the blood pressure waveform in the real time. It is realised directly by catheters. Also indirect unloading continuous plethysmografic technique of blood pressure waveform monitoring can be used. Even some instrument have been developed as described bellow, there does not exist any one widely used in medical care. The insufficient accuracy and stability for clinical purposes require the analysis of this non-linear system and the adaptive control description of the blood pressure waveform monitoring technique. New monitoring device has been designed Our aim is to design simple, low-cost and enough stable monitoring system that can be extended in medical praxis.

Electrical characterization of PEDOT:PSS

The purpose of this paper is to summarize the results of electrical measurements carried out on different types of metal-semiconductor heterojunctions based on PEDOT:PSS in order to examine the possibilities of either ohmic contacts or rectifying Schottky junctions formation. The character of created junctions was evaluated according to their I–V characteristics. Unusual electrical behaviour was observed in the case of heterojunctions formed on gold, platinum and carbon with a region of negative differential resistance. The phenomenon supposed to be partly responsible for such nonlinearity is existence of thin barrier layer on the surface of dried PEDOT:PSS, through which charge carriers could pass by tunneling. However, deeper investigation will be necessary to enlighten all the circumstances leading to origin of this behaviour.

Monitoring device of resin curing process

The presented article introduces a system for resin curing monitoring. The system is based on a combined sensor built on a ceramic substrate containing a heating element for independent surface heating, interdigital electrodes, and a Pt1000 thermistor for precise temperature measurements. The idea of the simple resin curing monitoring device is based on a small amount of tested resin being applied directly to the sensor surface. After the resin has been applied to the surface, a controlled heating process begins together with the measurement of the electrical properties of the resin, usually the impedance. The curing process is thus monitored and graphically plotted on the connected PC.

Measurement system for sensitive layers of carbon nanotubes

This paper deals with the design of the sensor structure for gaseous substances detection and with the design of suitable measurement system for sensitive layers of carbon nanotubes. The design and construction of the sensor structures is implemented as a universal platform enabling impedance changes measurement of deposited sensitive layers of carbon nanotubes together with the possibility of the sensor heating and independent temperature measurement. Designed system contains the sensor structure, evaluation circuits for signal processing and control circuits that allow electrical parameters measurement of different sensitive layers of carbon nanotubes. Based on this, the gas concentration is possible to determine.

Identification of fast-moving objects in frequency band 2.45 GHz

This paper describes system design for the identification of the fast-moving objects based on RFID frequency band 2,45 GHz. Reasons for using this frequency band 2,45 GHz are here summarized. Literature survey of available systems using this frequency band was done. Active tag and reader for identification fast-moving objects have been designed. The antenna and power supply design for active tags are involved. Experience finding can be utilized in the field of transportation for identification of vehicles, goods and other objects.

Phthalocyanine layers for humidity detection

This article deals with the research of different types of phthalocyanines for humidity detection. Thin layers of various phthalocyanines are exposed to water vapors and then electrical properties of these layers are measured. Potentially suitable materials are deposited on the substrates with interdigital electrodes and subsequently impedance-humidity characteristics are measured. Comparison of these materials, their features and responses to an ambient humidity are discussed in more detail.

Characterization of the organic field-effect transistor based on solution processed P3HT

The purpose of this paper is to present results of measurements taken on organic field effect transistors based on P3HT solution processed organic semiconductor. All discussed samples have been prepared both under ambient atmospheric conditions and in the dry nitrogen environment on rigid Si substrates covered with thermally grown SiO2 The electrical behaviour of OFETs has been subsequently examined under different test conditions. In particular, the overall device performance in normal room atmosphere as well as in the vacuum has been of special interest.