Universal Filter Based on Compact CMOS Structure of VDDDA.

This paper proposes the simulated and experimental results of a universal filter using the voltage differencing differential difference amplifier (VDDDA). Unlike the previous complementary metal oxide semiconductor (CMOS) structures of VDDDA that is present in the literature, the present one is compact and simple, owing to the employment of the multiple-input metal oxide semiconductor (MOS) transistor technique. The presented filter employs two VDDDAs, one resistor and two grounded capacitors, and it offers low-pass: LP, band-pass: BP, band-reject: BR, high-pass: HP and all-pass: AP responses with a unity passband voltage gain.

The Form of the Kedem-Katchalsky-Peusner Model Equations for Description of the Membrane Transport in Concentration Polarization Conditions.

The paper presents the Rr matrix form of Kedem-Katchalsky-Peusner equations for membrane transport of the non-homogeneous ternary non-electrolyte solutions. Peusner's coefficients Rijr and [Rr] (, ∈ {1, 2, 3}, = A, B) occurring in these equations, were calculated for Nephrophan biomembrane, glucose in aqueous ethanol solutions and two different settings of the solutions relative to the horizontally oriented membrane for concentration polarization conditions or homogeneity of solutions. Kedem-Katchalsky coefficients, measured for homogeneous and non-homogeneous solutions, were used for the calculations.

The Role of Gravity in the Evolution of the Concentration Field in the Electrochemical Membrane Cell.

The subject of the study was the osmotic volume transport of aqueous CuSO and/or ethanol solutions through a selective cellulose acetate membrane (Nephrophan). The effect of concentration of solution components, concentration polarization of solutions and configuration of the membrane system on the value of the volume osmotic flux ( J v i r ) in a single-membrane system in which the polymer membrane located in the horizontal plane was examined. The investigations were carried out under mechanical stirring conditions of the solutions and after it was turned off.

Simulation of -Entropy Production during the Transport of Non-Electrolyte Solutions in the Double-Membrane System.

Using the classical Kedem-Katchalsky' membrane transport theory, a mathematical model was developed and the original concentration volume flux (), solute flux () characteristics, and -entropy production by , ( ( ψ S ) J v ) and by ( ( ψ S ) J s ) in a double-membrane system were simulated. In this system, M and M membranes separated the , , and compartments containing homogeneous solutions of one non-electrolytic substance. The compartment consists of the infinitesimal layer of solution and its volume fulfills the condition → 0.

Refractive lens exchange.

Advances in small incision surgery have enabled cataract surgery to evolve from being concerned primarily with the safe removal of the opaque crystalline lens to a procedure refined to yield the best possible postoperative refractive result. As the outcomes of cataract surgery have improved, the use of lens surgery as a refractive modality in patients without cataracts (clear lens extraction) has increased in popularity. The removal of the crystalline lens for refractive purposes, or so-called refractive lens exchange (RLE), offers distinct advantages over corneal refractive surgery in selected cases.

Effect of sintering atmosphere on properties of porous stainless steel for biomedical applications.

This study discusses manufacturing of metallic biomaterials by means of powder metallurgy with consideration for their unquestionable advantages, i.e. opportunities of obtaining materials with controllable porosity.

Surface acoustic wave (SAW) vibration sensors.

In the paper a feasibility study on the use of surface acoustic wave (SAW) vibration sensors for electronic warning systems is presented. The system is assembled from concatenated SAW vibration sensors based on a SAW delay line manufactured on a surface of a piezoelectric plate. Vibrations of the plate are transformed into electric signals that allow identification of the sensor and localization of a threat.

Physical properties of iron-sulfur Fe6S6 superclusters important for biological systems.

The theoretical analysis of the thermal and magnetic properties of iron-sulfur superclusters has been studied by taking into account Heisenberg interactions and resonance delocalizations (double exchange interactions). The numerical calculations are based on the determination of the lowest energy states for different values of spins (from S = 0.5 to S = 12.

A 2D approach to tomographic image reconstruction using a Hopfield-type neural network.

Objective: In this paper a new approach to tomographic image reconstruction from projections is developed and investigated.

Method: To solve the reconstruction problem a special neural network which resembles a Hopfield net is proposed. The reconstruction process is performed during the minimizing of the energy function in this network.

Optical absorption of methoxy and carboethoxy derivatives of 1,3-diphenyl-1H-pyrazolo[3,4-b]quinoline.

Paper deals with experimental investigations and quantum chemical calculations of the optical absorption spectra of methoxy and carboethoxy 1,3-diphenyl derivatives of the pyrazoloquinoline ([PQ]): 6-methoxy-1,3-dyphenil-[PQ], 6-methoxy-1,3-(p-methoxyphenyl)-[PQ], 6-methoxy-1-(p-methoxyphenyl)-[PQ] and 6-carboethoxy-1,3-diphenyl-[PQ]. The quantum chemical calculations are performed by means of the semiempirical quantum chemical methods (AM1 or PM3) applied to: (a) the equilibrium molecular conformation in vacuo (T=0 K); (b) the molecular dynamic (MD) trajectory (T=300 K) which includes the dynamics of a certain molecular fragment (moiety) only (fragmental MD simulations); or (c) the MD trajectory obtained for most general case within the total MD simulations at T=300 K. The results of these calculations are compared with the measured spectra of the optical absorption.

Spatiotemporal characterization of interfacial Faraday waves by means of a light absorption technique.

We present measurements of the complete spatiotemporal Fourier spectrum of Faraday waves. The Faraday waves are generated at the interface of two immiscible index matched liquids of different density. By use of a light absorption technique we are able to determine the bifurcation scenario from the flat surface to the patterned state for each complex spatial and temporal Fourier component separately.

Optical poling effect and optical absorption of cyan, ethylcarboxyl and tert-buthyl derivatives of 1H-pyrazolo[3,4-b]quinoline: experiment and quantum-chemical simulations.

We present here results of experimental studies and quantum-chemical simulations of optical absorption and optical poling effects performed on a new synthesized cyan, ethylcarboxyl and tert-buthyl derivatives of 1H-pyrazolo[3,4-b]quinoline incorporated into polymer matrix or dissolved in organic solutions. The efficiency of second-order optical susceptibility d vs photoinduced power density I(p) clearly saturates to certain magnitude d(eff) at sufficient power densities (I(p) > or = 1.3 GW cm(-2)).

Generalized regression neural networks in time-varying environment.

The current state of knowledge regarding nonstationary processes is significantly poorer then in the case of stationary signals. In many applications, signals are treated as stationary only because in this way it is easier to analyze them; in fact, they are nonstationary. Nonstationary processes are undoubtedly more difficult to analyze and their diversity makes application of universal tools impossible.

Ion flotation of cadmium(II) and zinc(II) in the presence of proton-ionizable lariat ethers.

Competitive flotation of Cd(II) and Zn(II) from very dilute aqueous solutions by proton-ionizable lariat ethers in the presence of nonylphenol nona(ethylene glycol) ether as a nonionic foaming agent is reported. Influences of structural variation within the collector (identity of the pendent acidic group and lipophilicity), concentration of the collector, and pH of the aqueous solution are assessed. A monoethyl lariat ether phosphonic acid collector is found to exhibit high Cd(II)/Zn(II) flotation selectivity under certain conditions.

Volume osmotic flows of non-homogeneous electrolyte solutions through horizontally mounted membrane.

Results of an experimental study of volume osmotic flows in a single-membrane osmotic-diffusive cell, which contains a horizontal, microporous, symmetrical polymer membrane separating water and binary or ternary electrolyte solutions are presented. In the experimental set-up, water was placed on one side of the membrane. The opposite side of the membrane was exposed to binary or ternary solutions.

Finite element model of heat flow in biological tissue undergoing laser irradiation.

In this paper we present a numerical method to determine thermal effects in biological tissue undergoing laser irradiation. The scattering and absorption of the laser beam have been analysed. Results are compared with experimental observations.