A method of surface potential determination in semiconductors by means of the transverse acoustoelectric effect is described. The results of theoretical analysis of the transverse acoustoelectric voltage versus surface potential and different surface electrical parameters in indium phosphate single crystals are presented. The experimental results of the surface potential investigations have been obtained after various surface treatments in InP(110) and InP(100) crystals. A strong influence of the chemical and mechanical surface treatments upon the surface potential values has been observed from the measurements. The surface InP(110) was more sensitive to different surface treatments. The changes of the surface potential values were about two times greater for InP(110) than for InP(100) samples. The surface potentials after surface treatments obtained by the acoustics method were of the range -0.08 [V] to -0.22 [V].
The article presents preliminary research of an optical system for using in the temporary blood volume measurements in the Polish Ventricular Assist Device (POLVAD). The basis for the proposed solution is the measurement of the light reflected from the membrane in different configurations of light emitters and light detectors. The paper is describing a proposed measurement technique, measurement circuit and preliminary static measurements results of the developed measurement system. Future development plans are stated.
The "gold clinical standard" of cardiac output measurements is the thermodilution method, implemented by the Swan-Ganz catheter. The unreliability of obtained results is difficult to estimate experimentally, due to the lack of reference methods or the risk of serious interferences in the measured object. Moreover, the pulsating blood flow produced by the heart is difficult to measure. Therefore it is advisable to develop the physical model of the pulmonary circulation, designed to investigate the accuracy of cardiac output measurements by means of the thermodilution method.
The paper gives a short description of light guidance mechanisms of index-guided photonic-crystal fibres. The results of numerical analyses of photonic-crystal fibres with a suspended core are presented. Such fibres are planned to be applied for investigation of magneto-optic effects in gaseous media.
The possibility of using the transverse acoustoelectric phenomena in experimental investigations of near surface region in semiconductor crystals was discussed. The results of experimental investigations of GaP:Te(111) surfaces by means of the transverse acoustoelectric voltage were presented. Applying the transverse acoustoelectric voltage method, the lifetime τ of minority carrier in the near-surface region and the surface potential V_{s} in GaP:Te(111) surfaces after their different technological treatments were determined.
The photonic-crystal fibre with a suspended core was analyzed in order to explain possibilities of its using in investigation of electrooptic and magnetooptic effects occurring in the molecules of gas passed into air holes in the fibre. As results from numerical analysis, even 20% of electromagnetic optical energy can be propagating in the area of the air holes. The obtained results indicate the possibility of scanning the electrooptic and magnetooptic effects in photonic-crystal fibres with a suspended core in the case of considerable diminishing of the core (even below 1 μm) or in the case of light applying with its larger wavelengths.
The paper concerns analyses of the nanostructures based on metal-oxide semiconductors, such as titanium dioxide (TiO_2) and zinc oxide (ZnO) exposed to nitrogen dioxide (NO_2) in an atmosphere of dry and humid synthetic air. The investigations were performed at a rather low temperature amounting to 120°C. The responses of sensors differing in the morphology of their structures have been compared. Also the time of their responses were compared with each other. The paper describes theoretically changes in the effective resistance of these structures due to the interaction of the gas. The presented results are being discussed based on the analysis of physical and chemical phenomena.
The present paper deals with investigations concerning optical magnetic sensors. The most important advantage of sensors of this kind is their safety of service and insulating power. The insensitiveness of optical sensors to electromagnetic interference was discussed and experimentally investigated. The experimental investigations were concentrated on the adequate sensing fibre as well as on the sensor based on the bulk glass cylinder. The paper presents the results of magnetooptic tests of the elaborated magnetic field optical sensors and conclusions arise from them.
In gas sensing applications we often use sensors which have poor selectivity. Such sensors are mature, cheap devices with simple application circuits. Unfortunately, their cross sensitivity greatly restricts their usefulness when used in systems which employs univariate analysis. One method which allows to overcome this difficulty is utilization of multivariate analysis methods applied to the response from the group of such non-selective sensors. This work presents the multivariate, pattern recognition system utilized to process the response of an array of non-selective semiconductor sensors to obtain the qualitative information.
The paper presents the acoustic method for determining some parameters of fast surface states in semiconductors. This method uses the interactions of the phonon-electron type for determining both the effective carrier lifetime τ influenced by the fast surface energetic states and the velocity g of the carrier trapped by the surface states. Some experimental results of the parameters τ and g in near-surface region of real Si(111) samples for their various surface treatments, obtained by the offered method, are presented.
For an array of eight chemoresistive gas sensors a computer pattern recognition system was built. Multivariate data analysis was performed for measurements of three gases' dilutions: hydrogen (H_2), methane (CH_4), and carbon monoxide (CO). The pattern recognition system included a feature subset selection algorithm involving PCA and objective function. Dimensionality reduction was applied to two kinds of patterns: three aforementioned gases and six different concentrations of hydrogen. For patterns of the three gases, classification tests were performed using k-NN algorithm and N-fold based validation method.
The paper concentrates on the optical fibre sensors of electric current intensity. The specially elaborated glasses with high values of refractive indices were investigated in the prepared testing stand. The glasses have possessed the refractive index values n in the range 1.6 ≤ n ≤ 2.2. For the glasses the values of the Verdet constants for two waveguides: λ_1 = 635 nm and λ_2 = 1550 nm were determined. The obtained results showed that the elaborated on the base of new glasses optical fibres are much more sensitive on the action of magnetic field than the silica fibres.
One of the most fundamental examination in intensive care medicine is cardiac output measurement, realized by pulmonary artery catherization. The thermodilution cardiac output estimation method is not resistant to various kinds of disturbances, which significantly decreases its sensitivity and specificity. The paper depicts investigations related to analysis of presumable new source of unreliability - asymmetric blood flow through pulmonary vessels. The investigations consisted of two phases: clinical examination (to obtain anatomical data) and computer modeling (to simulate the flow symmetry).
The article presents researches concerning a system for a possible blood volume measurements applied in POLVAD prosthesis. The proposed solution is based on the Helmholtz resonance principle. The article shows the state of art in blood volume sensors for using in the POLVAD prosthesis and introduces a newly proposed solution. The construction of the sensor and the results of static tests are presented. The work is summarized with future development plans.
The present paper is focussed on the search of technology of new kinds of optical fibers characterised by good magnetooptical properties. The elaborated optical fibres are to apply in optical sensors of electric current and the magnetic field. In result of these researches and analyses a new optical fibre was put forward. Such optical fibers were designed, produced and subjected to extensive tests. This paper presents the results of investigations that were carried out as well as the parameters of the tested structures.
The present paper deals with investigations concerning optical fibre current sensors. They are mainly applied in measurements of the intensity of the electric current in the power lines as so-called optical transformers of the electrical current. The most important advantages of fibre current sensors are: safety of service, insulating power as well as their insensitiveness to electromagnetic interference. The investigations were concentrated on designing of adequate sensing fibre, and particularly on the choice of an adequate kind of glass, of which this fibre could be made. Besides, also the head of the fibre current sensor was designed, basing on the suggested and produced sensing fibre. The paper presents the results of magneto-optic tests of the glass and the sensing fibre.
Impedance cardiography is a non-invasive, cheap and easy to use method of long term hemodynamic monitoring. Nowadays this method is perceived as an alternative for invasive monitoring of the patients. The goal of the presented papers was to compare the results of rheocardiography with reference invasive monitoring.
The paper deals with the optical fibre current sensor based on new optical fibre made of glass with a high value of refractive index. This kind of glass was developed to meet the requirements of these optical fibres. The aim of investigations was to develop a new optical fibre with adequate magneto-optical properties and a relatively weak linear birefringence resulting from the process of its production. These features are of essential importance for optical fibre current sensors. The results of investigations concerning such optical fibres have been presented, displaying satisfactory magneto-optical properties, as well as only low linear birefringence induced by stresses arising in the course of their manufacturing.
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