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Recently ferroelectric properties have been found in hafnia-based nanosized films. Such films are of the utmost interest for development of a universal memory, which combines the advantages of random access memory and flash memory. The paper studies optical properties of hafnia-zirconium oxide films H-fxZryO2 and lanthanum-alloyed hafnia-zirconium oxide films La:HfxZryO2. Fluctuations of thickness in HfxZryO2 do not exceed 3.5%, fluctuations of thickness in La:HfxZryO2 films—3.2%. Optical properties are analyzed based on effective-medium theory. According to effective-medium theory data, HfxZryO2 films contain 46% HfO2, 54% ZrO2, La:HfxZryO2 films contain 47.5% HfO2, 52.4% ZrO2, 2.5% La2O3. [ABSTRACT FROM AUTHOR]

Currently, a new generation of high-speed, information-intensive resistive memory based on nonstoichiometric dielectrics is being developed. The electron structure of nonstoichiometric silicon oxide SiOx is set by the value of parameter x. It is found that the treatment of thermal SiO2 in hydrogen plasma electron cyclotron resonance leads to the enrichment of silicon oxide with excess silicon, which in turn leads to the appearance of electron and hole traps in SiOx. SiOx conductivity is bipolar: electrons are injected from negatively biased silicon and holes are injected from positively biased silicon. Cathodoluminescence (CL) experiments confirm the assumption that the traps in SiOx are due to the excess silicon. p++-Si(100)/SiOx/Ni memristor metal-dielectric-semiconductor (MDS) structures are fabricated based on the developed procedure for the preparation of nonstoichiometric oxide in hydrogen plasma of electron cyclotron resonance. Such structures have the properties of resistive switching of SiOx that do not require a forming operation. [ABSTRACT FROM AUTHOR]

Using the method of dielectrophoresis an optical cell detection system in an inhomogeneous alternating electric field, the electrical and viscoelastic parameters of red blood cells in the frequency range from 5 × 104 to 1 × 106 MHz have been studied in 129 patients with colorectal cancer (CRC) of various stages of the disease, 25 people with adenomatous polyps, and 35 people in the comparison group. It has been shown that the values of the physical characteristics of red blood cells significantly differ both when comparing the control groups and the patients with adenomatous polyps and the patients with early stages of CRC and when comparing the patients with different stages of the oncological process with each other. The construction of SHAP graphs based on the electrical and viscoelastic parameters of red blood cells has allowed us to achieve 100% diagnostic accuracy in distinguishing patients with adenomatous polyps and early stages of CRC from healthy individuals, 98.7% accuracy—in differentiating the patients with polyps from the patients with early stages of CRC, and 91.9% accuracy—in distinguishing early and late stages of CRC. The results obtained demonstrate the high potential of the proposed method for screening and diagnosing CRC. [ABSTRACT FROM AUTHOR]

The SiCOH low-k dielectric film was grown on Si substrate using plasma-enhanced chemical vapor deposition method. Atomic structure and optical properties of the film were studied with the use of X‑ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) absorption spectroscopy, Raman spectroscopy, and ellipsometry. Analysis of XPS data showed that the low-k dielectric film consists of Si–O4 bonds (83%) and Si–SiO3 bonds (17%). In FTIR spectra some red-shift of Si–O–Si valence (stretching) vibration mode frequency was observed in the low-k dielectric film compared with the frequency of this mode in thermally grown SiO2 film. The peaks related to absorbance by C–H bonds were observed in FTIR spectrum. According to Raman spectroscopy data, the film contained local Si–Si bonds and also C‒C bonds in the s–p3 and s–p2 hybridized forms. Scanning laser ellipsometry data show that the film is quite homogeneous, homogeneity of thickness is ~2.5%, and homogeneity of refractive index is ~2%. According to the analysis of spectral ellipsometry data, the film is porous (porosity is about 24%) and contains clusters of amorphous carbon (~7%). [ABSTRACT FROM AUTHOR]

The luminescent and optical properties of materials based on zirconium(IV) oxide grown by crystallization of ZrO2 melts with 0, 2.0, 2.5, 2.8, and 3.7 mol % of Y2O3 are studied. Using Raman spectroscopy, it is found that this material with the Y2O3 concentration below 2 mol % is mainly a monoclinic ZrO2 phase. The photoluminescence spectra of these crystals contain a blue–green band peaking at an energy of 2.4 eV. This fact in combination with the specific features of the refractive index and absorption coefficient dispersions indicates the presence of high concentrations of oxygen vacancies and polyvacancies in the samples. At higher concentrations of Y2O3 in the mixture, the tetragonal ZrO2 modification becomes dominant in the materials under study and the blue–green luminescence intensity decreases. The experimental optical spectra are analyzed in comparison with the ab initio calculated spectra for ideal ZrO2 crystals in the cubic, tetragonal, and monoclinic phases. [ABSTRACT FROM AUTHOR]

The optical properties and composition of thermal silicon oxide thin films processed in a hydrogen electron cyclotron resonance plasma have been studied by ellipsometry, quantum-chemical modeling, and photoluminescence spectroscopy. It has been found that the plasma processing of the films leads to their oxygen depletion and the formation of nonstoichiometric oxide SiOx< 2. The parameter x of the obtained SiOx films has been determined by comparing the experimental spectral dependence of the refractive index with the dependence obtained theoretically using the ab initio calculation. It is shown that an increase in the time of processing of thermal dioxide SiO2 in a hydrogen plasma leads to an increase in the refractive index of the film, as well as in the degree of its oxygen depletion. The dependence of the parameter x of the investigated films on the hydrogen plasma processing time is plotted. [ABSTRACT FROM AUTHOR]

The dielectric properties of the erythrocyte were studied. Experimental methods and results of measuring the dielectric properties of individual human erythrocyte are presented. The method is theoretically justified. It is found that values of the complex permittivity of the erythrocyte, electrical capacitance, dielectric loss tangent remain almost constant despite significant changes in conductivity and the content of NaCl in the cell suspension. These values reflect the stability of the studied parameters of erythrocytes under conditions of changes within a wide range of the environment in which the cells are located. Complex cell permittivity and cell dielectric loss tangent are promising parameters for objective diagnostics of human diseases. The introduction of measurements of cell permittivity and cell dielectric loss tangent into medical practice will likely allow us to characterize the process of individual cell self-regulation in more detail. [ABSTRACT FROM AUTHOR]

67 middle-aged (48 ± 1 years) patients with diffuse liver disease of various origins have been examined. It has been established that an increase in the degree of fibrosis is associated with an increase in the resonance intensity of glucose-6-phosphates, adenosine monophosphate (AMP), inosine monophosphate (IMP), pyrophosphates, and 2,3-bisphosphoglyceric acid (BPG) and a decrease in the resonances of inorganic phosphates and phosphocreatine, γ-, α-, and β-AMP, uridine triphosphate (UTP), Hb- and Mg-adenosine triphosphate (ATP), and β- and α- adenosine diphosphate (ADP). The predictive value of a positive result of 31P NMR spectroscopy of erythrocytes for liver fibrosis is 92.3% (the sensitivity is 85.71% and the specificity is 80%). In the IR spectra of the blood serum of patients with severe fibrosis, in contrast to the cases of moderate fibrosis, the resonance intensity is higher at 1280 and 3190 cm‒1 and significantly lower at 776, 818, 889, 966, 1399, 1450, 1570, and 1635 cm‒1, which indicates the presence of protein molecules with a secondary structure mainly in the form of a spiral (α helix), in contrast to the structure in the form of a folded sheet (β sheet) at p < 0.001‒0.05. The combined use of 31P NMR spectroscopy of erythrocyte suspensions and IR spectroscopy of blood serum made it possible to increase the diagnostic accuracy (96%), sensitivity (97%), and specificity (91%) in distinguishing the degrees of liver fibrosis as compared with the separate use of these techniques. [ABSTRACT FROM AUTHOR]

The optical properties of amorphous nonstoichiometric silicon oxide (SiOx) films of variable composition (x = 0.62–1.92) formed by plasma-enhanced chemical vapor deposition are studied in the spectral range of 1.12–4.96 eV. Spectral ellipsometry showed that the refractive index dispersion character allows one to assign the formed SiOx films to silicon-like films, dielectrics, or intermediate-conductivity-type films depending on the content of oxygen in the gas phase during synthesis. A model of the SiOx structure for ab initio calculations is proposed and describes well the experimental optical spectra. Ab initio calculations of the dependences of the SiOx refractive index and band gap on stoichiometry parameter x are performed. [ABSTRACT FROM AUTHOR]

The atomic structure and the electronic spectrum of a-SiNx:H films, which are grown by plasmachemical deposition with varied ammonia and monosilane flow rates, are studied. As a result of varied flow rates, stoichiometric parameter x is changed over wide limits, from 0.73 to 1.33. The films are analyzed by structural and optical techniques to determine stoichiometric parameter x and its influence on the valence band top and the band gap in the density of states. The experimental and calculated electronic structure parameters of a-SiNx are compared, and good agreement between them is achieved over wide film composition (parameter x) limits. The experimental data obtained can be used to simulate the electron transport characteristics in nonstoichiometric silicon nitride films, which is important for creating memristors based on them. [ABSTRACT FROM AUTHOR]

Diagnostic pilot monitoring of the groups of healthy patients and patients with colorectal cancer (CRC) at different stages of the disease was carried out using Raman spectroscopy (RS) and measuring the state of polarized light near the conditions of observation of surface plasmon resonance (SPR). The reaction of the blood serum antigens with antibodies to serum M2 pyruvate kinase (M2-PK) nears the conditions of observation of SPR was used for diagnosing; for this, the Ellipse-SPEC spectral ellipsometric complex created at the Rzhanov Institute of Semiconductor Physics (Siberian Branch, Russian Academy of Sciences) and having a high sensitivity, accuracy, and nondestructive nature of the effect on the studied sample, was used in the work. The peak intensities at 1005, 1157, and 1520 cm–1 in Raman spectra in CRC patients as compared with healthy individuals (as well as the intensity of surface plasmon resonance) were significantly lower, correlating with the stage of the disease and the presence of metastases; this allows to consider these optical methods for studying the blood serum as promising diagnostic approaches in diagnosis CRC, including in the early stages of the disease. [ABSTRACT FROM AUTHOR]

The possibilities of using electrical and viscoelastic parameters of erythrocytes in patients with colorectal cancer (CRC) of different stages were demonstrated using optical cell detection system based on the dielectrophoresis method. The deformation amplitude, portion of deformed cells, generalized viscosity, rigidity, equilibrium frequency position, and electrical conductivity were the most significant parameters for determining patients with CRC, as well as early and late stages, included in the created model of a riskometer for the disease diagnosis. The created diagnostic "panels" with a high diagnostic accuracy, sensitivity, and specificity allowed to one determine patients with CRC (specificity 0.91, sensitivity 0.96), as well as early and late stages of the disease (specificity 0.64, sensitivity 0.86). [ABSTRACT FROM AUTHOR]

The optical quality HfxTi1−xO2 films with a wide range of the Hf/Ti ratio were prepared on Si (100) substrates by the ALD method with the use of tetrakis(ethylmethylamido)hafnium(IV) (Hf(NC2H5CH3)4, TEMAH) and titanium(IV) chloride TiCl4 as Hf and Ti precursors, respectively. The H2O vapor was applied as oxygen source. The structural properties of the as-deposited and annealed films were evaluated by the XRD analysis. The Hf/Ti ratio in the films was measured by energy dispersive spectroscopy and X-ray photoelectron spectroscopy. The dispersive optical constants were obtained by spectroscopic ellipsometry over the photon energy range of E = 1.12-4.96 eV. The specific growth kinetics is observed for 0 < x < 1. The optical constants wide-range tuning is reached in the HfxTi1−xO2 (x = 0-1) films via the chemical composition variation and annealing. [ABSTRACT FROM AUTHOR]

Abstract: The optical properties of thin films based on unsubstituted and tetrafluoro-substituted zinc phthalocyanines synthesized by physical vapor deposition are studied within the wavelength range of 250-1000 nm. Spectroscopic ellipsometry shows that films based on zinc phthalocyanines have uniform thicknesses and optical parameters, strongly absorb visible light, and have characteristic absorption peaks corresponding to electronic transitions in the system of conjugated double bonds of phthalocyanine rings. Introduction of fluorine substituents into peripheral positions of the zinc phthalocyanine molecule leads to an increase in light absorption and a shift of the main absorption maximum to longer wavelengths (bathochromic shift). The absorption spectra are described using the Lorentz-Drude dispersion model. It is shown that the films based on a mixture of phthalocyanines can be well described using the Bruggeman effective medium model. [ABSTRACT FROM AUTHOR]

The atomic and electronic structures of metal-rich noncentrosymmetric zirconium oxide synthesized by the ion beam sputtering of a metallic target in an oxygen atmosphere has been studied by X-ray photoelectron spectroscopy, Raman scattering, spectral ellipsometry, and quantum-chemical simulation. It has been established that ZrOx < 2 consists of ZrO2, metallic Zr, and zirconium suboxides ZrOy. The stoichiometry parameter of ZrOy has been estimated. It has been shown that the optical properties of ZrOx < 2 are determined by metallic Zr. A model of fluctuation of the width of the band gap and a potential for electrons and holes in ZrOx < 2 based on spatial fluctuations of the chemical composition has been proposed. [ABSTRACT FROM AUTHOR]

The atomic and electronic structures of metal-rich noncentrosymmetric zirconium oxide synthesized by the ion beam sputtering of a metallic target in an oxygen atmosphere has been studied by X-ray photoelectron spectroscopy, Raman scattering, spectral ellipsometry, and quantum-chemical simulation. It has been established that ZrOx < 2 consists of ZrO2, metallic Zr, and zirconium suboxides ZrOy. The stoichiometry parameter of ZrOy has been estimated. It has been shown that the optical properties of ZrOx < 2 are determined by metallic Zr. A model of fluctuation of the width of the band gap and a potential for electrons and holes in ZrOx < 2 based on spatial fluctuations of the chemical composition has been proposed. [ABSTRACT FROM AUTHOR]

Optical properties of amorphous nonstoichiometric tantalum-oxide films of variable composition (TaOx, x = 1.94-2.51) in the spectral range of 1.12-4.96 eV, obtained by ion-beam sputtering-deposition of metallic tantalum at different partial oxygen pressures (0.53-9.09 × 10-3 Pa), have been investigated. It is shown by spectral ellipsometry that the character of dispersion of the absorption coefficient and refractive index in TaOx of variable composition suggests that light-absorbing films with dispersion similar to that in metals are formed at oxygen pressures in the growth chamber below 2.21 × 10-3 Pa, whereas transparent films with dielectric dispersion are formed at pressures above 2.81 × 10-3 Pa. According to the data of quantumchemical simulation, the absorption peak at a photon energy of 4.6 eV in TaOx observed in the absorptioncoefficient dispersion spectrum is due to oxygen vacancy. The peak in the Raman-scattering spectra of TaOx films with metallic dispersion at frequencies of 200-230 cm-1 is presumably related to tantalum nanoclusters. [ABSTRACT FROM AUTHOR]

The microstructures of amorphous and polycrystalline ferroelectric Hf0.5Zr0.5O2 films are studied by X-ray spectroscopy and ellipsometry. EXAFS spectra demonstrate that the amorphous film consists of an “incompletely mixed” solid solution of metallic oxides HfO2 and ZrO2. After rapid thermal annealing, the mixed Hf0.5Zr0.5O2 oxide films have a more ordered polycrystalline structure, and individual Hf and Zr monoxide islands are formed in the films. These islands are several nanometers in size and have a structure that is similar to the monoclinic structure of HfO2 and ZrO2. The presence of the HfO2 and ZrO2 phases in the Hf0.5Zr0.5O2 films is also detected by ellipsometry. [ABSTRACT FROM AUTHOR]

A brief review of the optical properties of oxide materials that are used at present as dielectrics in modern microelectronics is presented. Using spectral ellipsometry, dispersion dependencies for different materials are measured. A brief comparative analysis of different dielectric coatings is carried out. The results of our research will be useful in further studies of the properties of dielectrics, as well as in technologies that are employed in the development of new semiconductor instruments and devices. [ABSTRACT FROM AUTHOR]

Titanium dioxide (anatase, a-TiO) films have been prepared by electron beam sputtering of a TiO target in reactive atmosphere and their structural, microstructural, and optical properties were evaluated by reflection high- energy electron diffraction (RHEED) and x-ray diffraction (XRD) analyses, atomic force microscopy (AFM), and spectroscopic ellipsometry (SE). Different reflection models for determination of film optical parameters were tested and compared. The dispersive optical parameters were defined using the Tauc-Lorentz model by SE in the photon energy range of E = 1.12-4.96 eV. The films were transparent at E < 3 eV, but noticeable absorption was detected at E > 3 eV. The bandgap was estimated at the level of E ≈ 3.44 eV. [ABSTRACT FROM AUTHOR]

Amorphous nonstoichiometric ZrO films of different composition have been synthesized by the method of ion-beam sputtering deposition of metallic zirconium in the presence of oxygen at different partial oxygen pressures in the growth zone, and their optical properties have been studied in the spectral range of 1.12-4.96 eV. It is found that light-absorbing films with metallic conductivity are formed at the partial oxygen pressure below 1.04 × 10 Pa and transparent films with dielectric conductivity are formed at the pressure above 1.50 × 10 Pa. It is shown that the spectral dependences of optical constants of ZrO films are described well by the corresponding dispersion models: the Cauchy polynomial model for films with dielectric conductivity and the Lorentz-Drude oscillator model for films with metallic conductivity. [ABSTRACT FROM AUTHOR]

A terahertz ellipsometer, based on the Novosibirsk free electron laser (FEL), is described. The device operates using the dynamic photometric 'polarizer-sample-analyzer' scheme with a rotating analyzer. Sources of systematic errors, attributed to imperfections of optical elements, the accuracy of their alignment, and the influence of random errors, which are caused by measuring-section noises, were analyzed. The whole device and its separate units were tested. From results of measurements on tested samples, the operation accuracy of the ellipsometer was determined: δΨ ⩽ 0.3° and δ(cosΔ) ⩽ 0.01. The measurement data obtained at a wavelength of 147 μm on the thickness and reflective index of blood films, which were deposited on a silicon substrate, are presented. In this case, the measurement accuracy of the reflective index is ±0.05 and thickness is 0.2 μm. [ABSTRACT FROM AUTHOR]

An ellipsometric in situ study of the growth of porous aluminum anodic oxide films on aluminum substrate has been performed. Theoretical calculations have been carried out to interpret the experimental dependences of ellipsometric parameters; they made it possible to identify the most characteristic details of anodic oxidation. It is shown that the ellipsometric method allows one to control in situ in real time a number of important layer parameters: growth rate, porosity, depth uniformity, and the state of interface. The ellipsometric measurements have also revealed high sensitivity to the presence of metal nanoparticles both in the bulk of a layer and on its surface. [ABSTRACT FROM AUTHOR]

The formation of hafnium oxide (HfO) layers in slit structures by pulsed metalorganic chemicalvapor deposition (MOCVD) method with discrete dosage of reactants has been studied. The MOCVD process employed hafnium tetrakisdipivaloylmethanate as a precursor and oxygen as a gaseous reactant. The slit structure was formed by a silicon plate and a glass substrate with a chromium-film pattern. The slit width was varied within 0.1-2.0 mm, so that the aspect ratio changed from 150 to 30. The deposited layers were studied by the scanning ellipsometry technique. The phenomenon of image transfer from the glass substrate to the opposite plate in the form of a nanosized HfO film relief, which reproduces the chromium-film pattern, is discovered. The in-plane resolution of the obtained image in these experiments reached 0.025 mm. This effect can be used for nonlithographic formation of images of film structures. [ABSTRACT FROM AUTHOR]

The optical properties of the highly-textured VO thin-films grown on Si(100) by sputter-deposition at various oxygen reactive-pressures were investigated in detail. The profiles of the optical constants, namely the refractive index and extinction coefficient, of VO films were evaluated in the photon-energy range of 1-5 eV. At photon-energy above 2.5 eV, the dispersion behavior in optical constants is explained based on Lorentz-Drude model. The refractive index dispersion fits to a Cauchy's relation at photon-energy below 2.5 eV, where the VO-film is mostly transparent. The optical transitions across the bandgap occur at energy ∼2.5-3.2 eV depending on the VO growth conditions and film-microstructure. The highly-textured and c-axis oriented VO-films, fabricated under optimum conditions of temperature and oxygen partial pressure, exhibit excellent optical characteristics similar to VO single crystals. [ABSTRACT FROM AUTHOR]

To date, the complex evaluation of physical and dispersive optical characteristics of the ZrON/Si film system has yet been reported. Hence, ZrON thin films have been formed on Si(100) substrates through oxidation/nitridation of sputtered metallic Zr in NO environment at 500, 700, and 900 C. Physical properties of the deposited films have been characterized by X-ray diffractometry (XRD), Fourier transform infrared (FTIR) spectroscopy, reflection high-energy electron diffraction (RHEED), and spectroscopic ellipsometry (SE). It has been shown that ZrON/Si thin films without optical absorption can be prepared by oxidation/nitridation reaction in NO environment at 700-900 C. [ABSTRACT FROM AUTHOR]

The effect of the electrolyte composition on the surface morphology and the dispersion dependences of the refractive index and extinction coefficient of ∼20-nm-thick anodic layers on InAs (111)III substrates is studied by atomic force microscopy and spectral ellipsometry. It is shown that oxidation in electrolytes with different acidities does not modify the surface morphology of the initial InAs substrates. The films formed upon oxidation exhibit close dispersion dependences, despite the difference in the chemical composition between the films. This makes possible the high-precision monitoring of the thickness of anodic layers on InAs substrates by means of ellipsometry with the optical model of a single-layer isotropic film on an absorbing substrate. [ABSTRACT FROM AUTHOR]

Thin films obtained by centrifugation of blood serum of healthy people and patients with diffuse pathology of liver with different degrees of fibrosis are studied by means of spectroscopic ellipsometry. The physical properties of the films are found to depend on the bio-organic composition of blood serum, which, in turn, is determined by pathological processes proceeding at different degrees of liver fibrosis. Correlations between the bio-chemical parameters of blood serum and ellipsometric data are obtained. Pilot ellipsometric experiments on studying blood serum with observations of the plasmon resonance of patients with intestinal tract tumors are performed. A persistent specific interaction between antigens of patient's blood serum and SD24 monoclonal antibodies is found, which alters the position of the surface plasmon resonance. It is demonstrated that ellipsometry is a high-sensitivity nondestructive inexpensive express method of screening, i.e., preliminary diagnostics of disease stages for patients with pathologies of internals. [ABSTRACT FROM AUTHOR]

The surface of biochips prepared on the basis of silicon wafers for studies of reactions of pre-immobilized oligonucleotides and protein molecules was analyzed by high-resolution scanning ellipsometry. The hybridization interactions of nucleic acid (duplex formation in the reaction of an amplicon of the influenza A virus matrix protein gene with probe molecules), sorption of protein molecules, and protein-protein interactions on the surface of the biochip were detected. It was shown that pre-sorption of gold nanoparticles led to greater efficiency of immobilization of protein molecules on the biochip. The experimental data suggest that that ellipsometry is a highly sensitive, nondestructive and inexpensive label-free method for the detection of the biochip surface, which is suitable for quantitative analysis of reactions of biomolecules. [ABSTRACT FROM AUTHOR]

Thin films obtained by centrifugation of blood serum of healthy people and people with viscera diseases are studied by methods of spectral ellipsometry and infrared spectroscopy. Physical properties of such films are found to depend on the bio-organic composition of blood serum, which, in turn, is determined by pathological processes proceeding in the human organism. It is of interest that spectral ellipsometry and infrared spectroscopy are suitable nondestructive express methods of screening, i.e., preliminary blood diagnostics for patients with viscera pathology. Ellipsometric data on specific features of formation of bio-organic coatings from blood serum of patients with diffuse pathology of liver, hyperlipidemia, and diabetes mellitus are validated by changes in the fine structure of infrared spectra. [ABSTRACT FROM AUTHOR]

series of technological experiments on the growth of GaSe:Te single crystals by the Bridgman-Stockbarger method is performed. Surface micromorphology and mechanical properties of crystals with different doping levels are studied. Spectral dependences of the complex refractive index are obtained using ellipsometry. The experimental data are approximated within the Lorentz-Drude model. [ABSTRACT FROM AUTHOR]

This paper gives the results of measurement of shock-induced electrical conductivity in ferroelectrics: PKR-1 lead zirconate-titanate piezoceramic, deuterated triglycerine sulphate single crystal, and polymer polyvinylidene fluoride. [ABSTRACT FROM AUTHOR]

We present recurrence formulas for the number of partitions of a natural number n whose parts must be not less than m. A simple proof of Euler’s formula for the number of partitions is given. We construct the triangle of partitions, put forward conjectures concerning the properties of the triangle, and propose an algorithm for calculating the partitions. An original graphical interpretation for the partition function is presented. [ABSTRACT FROM AUTHOR]

Optical characteristics of the HfO2 − xN x and TiO2 − xN x films obtained by reactive ion beam sputtering have been investigated by spectral ellipsometry. The chemical composition of the films was determined using X-ray photoelectron spectroscopy. The nitrogen content in the oxynitride films (determined by the N2/O2 ratio in the gas mixture during synthesis) reached ≈9 at % for TiO2 − xN x and ≈ 6 at % for HfO2 − xN x. It is found that the dispersion relations n(λ) and k(λ) for the TiO2 − xN x films change from those characteristic of titanium dioxide to those typical of titanium nitride with an increase in the nitrogen content from 0 to ≈9 at %. The optical parameters of the HfO2 − xN x films depend weakly on the nitrogen content in the range 0–6 at %. [ABSTRACT FROM AUTHOR]

Technologies for manufacturing and poling the dynamic pressure gage based on ferroelectric polyvinylidene fluoride polymer are described. Results of theoretical and methodical investigations of the gage and pressure profiles measured with this gage behind the shock wave front in solids are presented. [ABSTRACT FROM AUTHOR]

A method is proposed to measure shock-induced electrical conductivity in electrically active dielectrics — piezoelectrics and ferroelectrics. Results of measurements of electrical conductivity in single-crystal quartz are reported. [ABSTRACT FROM AUTHOR]

The paper presents a physical model of a pressure gauge based on polyvinylidene fluoride, a ferroelectric polymer. At pressures of 1–36 GPa, the model agrees with experimental results. [ABSTRACT FROM AUTHOR]

A delayed visual differentiation task using stimuli of different colors was used in rhesus macaques to study the characteristics of visual recognition, short-term memory, and the responses of neurons recorded simultaneously in the visual and prefrontal areas of the cortex, along with their relationships with the site of intracortical (fields 17 or 46) perfusion of the glutamate receptor antagonist 2-amino-5-phosphonovaleric acid (APV). The behavioral characteristics and spike activity of individual cells in cortical fields 17 and 46 were recorded before and after perfusion with APV and after washing away of traces of APV. Multifactor dispersion analysis showed that the effect of APV in monkeys consisted of decreases in the probability of correct responses, leading to a decrease (two-fold) in the duration of short-term storage of information and a significant increase in the motor reaction time. The probability of correct solutions depended on the site of APV perfusion in the cortex, while the motor response time was independent of the perfusion site. Perfusion of field 46 with APV, unlike perfusion of field 17, altered the spike activity only of neurons in the prefrontal cortex, while no significant changes were seen in the neuron activity of the visual cortex. The actions of APV were accompanied by significant desynchronization of neuron activity in these two areas as compared with the level of synchronization in normal conditions; after traces of APV were washed away, the extent of desynchronization decreased. The neurophysiological correlates of cognitive dysfunctions associated with degradation of visual recognition and short-term memory due to modification of glutamatergic structures by blockade of NMDA receptors are discussed. [ABSTRACT FROM AUTHOR]

The effects of perfusion of field 17 with the glutamate receptor antagonist 2-amino-5-phosphonovaleric acid (APV) on the characteristics of visual recognition and short-term memory were studied, along with the effects of APV on the responses of neurons in the visual and prefrontal areas of the cortex in rhesus macaques. In the test for delayed visual differentiation of stimuli of different colors, behavioral data were recorded simultaneously with multichannel recordings of the spike activity of single cells in cortical field 17 (directly within the microdialysis zone) and field 8. Multifactor dispersion analysis (ANOVA) showed that APV significantly worsened the behavioral characteristics in monkeys, with significant reductions in the duration of short-term storage of information (by factors of 2–4) and significant increases in the motor response times. These changes in cognitive characteristics induced by APV were accompanied by changes in the spike activity of neurons in the visual and prefrontal areas of the cortex during the sensory analysis and delay stages; changes in spike activity consisted of significant desynchronization. These results show that cognitive dysfunctions consisting of worsening of short-term remembering of information and increases in the duration of motor responses during exposure to APV may be caused by desynchronization of neuron activity in various areas of the cortex, these being involved in neuron ensembles responsible for the mechanisms of short-term memory, in which glutamatergic structures play an important role. [ABSTRACT FROM AUTHOR]

Behavioral experiments were carried out in which monkeys had to solve a task involving delayed visual discrimination, and activity was simultaneously recorded from several neurons of the visual, prefrontal, and lower temporal regions of the cortex before and after modification of cholinergic (by systemic infusion of the M-cholinoceptor blocker amizil) and glutaminergic (by intracortical perfusion with glutaminergic agonists and antagonists, i.e., NMDA, aminophosphonovalerianic acid (APV) and aminophosphonobutyric acid (APB)) systems. Amizil and APV reduced the duration of short-term information retention and increased the delay before the motor response was made. Worsening of these parameters was accompanied by a significant level of desynchronization of activity in the groups of neurons studied. NMDA and APB improved short-term memory and increased neuron synchronization. The role of synchronization of information processes in the mechanisms of short-term memory and the involvement of the cholinergic and glutaminergic systems are discussed. [ABSTRACT FROM AUTHOR]

The effect of intracortical perfusion with the glutamate agonist NMDA on visual recognition and short-term memory, as well as on the responses of visual cortex neurons, were studied in rhesus macaques. A microdialysis technique was used in combination with multichannel microelectrode recording of single cortical cells in the immediate vicinity of the dialysis tube in a behavioral experiment in which the monkey had to solve a task involving delayed visual differentiation of stimuli of different colors. NMDA altered the characteristics of recognition in monkeys. The duration of information storage in short-term memory was increased significantly (2–4-fold), and there was a significant reduction in the motor response time for all delay periods. These changes were accompanied by a significant rearrangement of neuron activity in the visual cortex at all stages of the behavioral task. At different stages of the task, 70–85% of the neurons showed 2–5-fold increases in activity, while 6–20% showed reductions in activity. These results demonstrate an involvement of visual cortex glutaminergic structures in the processes of visual recognition and short-term memory, as well as a nootropic effect obtained by intracortical administration of NMDA. [ABSTRACT FROM AUTHOR]

The effects of modification of NMDA-ergic structures by microdialysis perfusion in the prefrontal cortex (field 8) with NMDA glutamate (2 mM) on visual recognition and short-term memory (STM) were studied in rhesus macaques, using methods based on the deferred differentiation of stimuli of different colors. Impulse activity of neurons in the prefrontal and visual cortex was measured during these experiments, both before and after administration of NMDA. NMDA increased (2-fold) the duration of short-term retention of information and significantly reduced the latent period of the motor response at all delay periods, and also produced significant changes in neuron activity in the prefrontal cortex: depending on the stage of behavior, activity decreased in 60-75% of neurons and increased in 8-26%. NMDA produced significant increases in the cross-correlation coefficients between the responses of neurons in the visual and prefrontal cortex. The results showed that glutaminergic structures in the prefrontal cortex are involved in processes of visual recognition and STM in monkeys. The effect of NMDA, which synchronized cortical neuronal processes, improved the short-term understanding of visual information. [ABSTRACT FROM AUTHOR]

A model of brief oxygen supply disruption was created in monkeys trained to a delayed visual spatial choice. A substantial reorganization of the impulse activity of neurons of the visual and prefrontal cerebral cortex, accompanied by disturbances in behavioral reactions, was observed during brief hypoxia (2.5 min); the motor reaction was not restored for several hours in the monkeys during a delayed visual spatial choice. The reorganization of the activity consisted in the appearance of successive phases of hyperactivation and inhibition. The frequency of the impulse activity in the phase of hyperactivation was higher in prefrontal cortex neurons. Successive phases of inhibition and hyperactivation were also identified in the posthypoxic period of restoration in the structure of the activity. The duration of the posthypoxic inhibition and the ratio of the frequencies of posthypoxic hyperactivation to the baseline frequency in the reactions of prefrontal cortex neurons was substantially greater than in the neurons of the visual cortex. [ABSTRACT FROM AUTHOR]

The impulse activity of groups of neurons of the visual, prefrontal, and inferotemporal cortex was recorded simultaneously in behavioral experiments on monkeys solving a problem of delayed visual differentiation of variously colored stimuli. The neurophysiological correlates of the decision-making processes were studied. Erroneous motoric reactions were accompanied in all monkeys by significant reorganizations of the patterns of impulse activity of the neurons. In the case of correct solutions of the monkeys, synchronization in time and cross-correlation which was significant in magnitude between the activity of the groups of neurons were observed. Incorrect solutions were accompanied by desynchronization and by a decrease in cross-correlation between the activity of these groups of neurons. Possible decision-making mechanisms and the causes of the desynchronization of the informational processes during erroneous reactions are discussed. [ABSTRACT FROM AUTHOR]

The influence of an effective antioxidant, oxymethacil, was studied in a model of the disruption of visual recognition induced by the antidepressant fluoracyzine. The normal discrimination of black and white visual stimuli in monkeys is restored with the systemic administration of oxymethacil in a dose of 3 mg/ kg following disruption brought about by the effect of fluoracyzine. The discrimination of colored visual stimuli, as in the norm, is restored following the systemic administration of oxymethacil in a dose of 4 mg/kg. The results obtained attest to the corrective properties of oxymethacil. [ABSTRACT FROM AUTHOR]

Monkeys performed a task of delayed visual differentiation of differently colored stimuli in behavioral experiments. The impulse activity of individual neurons of the prefrontal and inferotemporal cortex before and after the systemic administration of a blocker of M-cholinoreceptors, amyzil (0.8-1.0 mg/kg), was recorded simultaneously. Deterioration of the characteristics of recognition induced by amyzil was accompanied mainly by a significant increase in the activity of neurons of the prefrontal cortex which was dependant on the stage of recognition, and intensified with an increase in the delay interval. The impulse activity of the neurons of the inferotemporal cortex varied in the process without a regular pattern: at some stages of recognition it increased, at others it was inhibited. Amyzil induced a substantial decrease in the coefficients of cross correlation between the simultaneous respondent reactions of groups of neurons of the prefrontal and inferotemporal cortex. The results obtained point to the fact that the cholinergic structures of the inferotemporal and prefrontal cortex participate, at various stages of visual recognition in monkeys, in the formation of the dynamic functional systems which make their specific contribution to informational processes. [ABSTRACT FROM AUTHOR]

The impulse activity of individual neurons of the prefrontal and inferotemporal cortex was recorded during the performance of a task of delayed visual differentiation of stimuli of various colors in monkeys before and after the systemic administration of the antioxidant, oxymethacil (4-5 mg/kg). The improvement in cognitive characteristics induced by oxymethacil was accompanied by changes in the activity of neurons of the prefrontal cortex in which activation dependant upon the stage of recognition and intensifying during an increase in the duration of the delay predominated. Inhibition of activity predominated during recognition without delay in these neurons; by contrast, activation predominated in neurons of the inferotemporal cortex under these conditions. During delayed differentiation, the activity of these neurons under the influence of oxymethacil changed principally in the same way as in neurons of the prefrontal cortex: activation predominated in the majority of the stages of recognition. Oxymethacil induced a substantial increase in the coefficients of cross correlation between simultaneous respondent reactions of groups of neurons in these different areas of the cortex. The results obtained attest to the contribution of neuronal structures of the prefrontal and inferotemporal cortex to the improvement of cognitive characteristics of monkeys in the presence of the effect of oxymethacil, and to the increase in synchronization of informational processes in these regions of the cortex. [ABSTRACT FROM AUTHOR]

After the injection of the antioxidant, oxymethacil (4-5 μg/kg), in an investigation in monkeys of the processes of delayed visual recognition, their cognitive characteristics were significantly improved.: the duration of the short-term storage of information increased (by a factor of 2-3) and the time of the motor reaction decreased. The improvement of the cognitive characteristics was accompanied by changes in the neuronal activity in the visual cortex at all stages of recognition. The activity of the majority of the neurons increased in the case of discrimination without delay; it decreased significantly in the case of delayed discrimination. The administration of oxymethacil induced an increase in the auto-and cross-correlation coefficients in the respondent reactions of the recorded groups of neurons. The results obtained suggest that oxymethacil possesses nootropic properties, and the participation of the visual cortex of monkeys in the realization of these properties for the improvement of cognitive characteristics. [ABSTRACT FROM AUTHOR]

The activity of individual neurons of the visual cortex was recorded simultaneously in behavioral experiments on monkeys before and after the systemic administration of a blocker of M-cholinoreceptors, amizil (0.8-1.0 mg/kg). The animals were trained to delayed visual differentiation of stimuli of various colors. After the administration of amizil, the characteristics of recognition deteriorated substantially: the duration of the storage of information in short-term memory sharply declined, while the time of the motoric reaction increased. The deterioration of these characteristics was accompanied by inhibition of the activity of the neurons of the visual cortex, inhibition which depended on the stage of recognition, and which intensified when there was an increase in the delay interval. The results obtained suggest that cholinergic mechanisms of the visual cortex are included in visual recognition, and apparently play various functional roles at various stages of behavior. [ABSTRACT FROM AUTHOR]

The sensitivity of chemical sensors depends on the number of receptors on the surface; hence, an important role is played by the accessible support surface. Films based on silica mesoporous mesophase materials feature the highest specific surface area for silica materials, and their walls can be modified by various functional groups. In this paper, we propose to use mesoporous mesophase films as supports of sensitive elements for Cr3+ ions. [ABSTRACT FROM AUTHOR]