All articles - Electrochemistry

Subjects of research: the basic object of research is silk fibroin and wool keratin. For comparative experiences is chosen copolymer of acrilonytrilc. As the solvents the systems 2,5 M LiCl-DMFA, 2,5 M NaOH-water and 7,7 M NaCNS-watcr arc used.
Purpose of work: consists in revealing laws of dcformational and orientational structure formation of fibroin and keratin at the non-newton stream of solutions and ions electrodialysis also definition of clcctroconductivity characteristics of received gels and besieged samples, containing residual ions.
Method of research: rheooptimetry, birefringence, dispersion optical rotation, polarization ultramicroscope, viscosimetry, potentiometry, electrodialysis, ampermetry.
The results obtained and their novelty': the features of education of solutions of fibroin and keratin in the ion containing the solvents are revealed and the critical parameters for a choice of a biopolymeric solution allowing to realize non-newton stream and ions electrodialysis arc established; representing structural organizations and interactions of electrodialysis for the first time arc found out the hysteresis effects at non-newton stream of solutions generated in the shift and longitudinal fields; opportunities of dcformational and orientational structure formation of fibroin and keratin for the first time are revealed at the non-newton stream of solutions with intensive removal of ions by means of electrodialysis; the conditions of reception gels and besieged samples of fibrillar proteins with high degrees of the factor of orientation of circuits and small quantity of residual ions determined; Arc determined of electroconductivity characteristics of received gels and besieged of fibrillar proteins depending on a degree of ordering macromolecules and contents of ions in samples; the installations rheooptimetry, complemented with electrodialysis for the investigations of structure formation arc assembled at the non-newton stream in conditions of intensive removal of ions.
Practical value: revealed of dcformational and orientational of behaviour of of fibroin and keratin and also them hysteresis effects in the non-newton stream have the important meaning in development of fundamental representations about dynamics ordered structure formation of fibrillar proteins from solutions; the revealed laws of education of solutions, gels and besieged samples of fibroin and keratin at the presence of ions of salts and alkalis, and also them electroconductivity characteristics can be useful to development of scientific principles of processing fibrous wastes of silk and wool with reception of biomaterials with specific physical properties; the specially assembled experimental by generation non-newton stream and ions electrodialysis represent the large interest for research ordered structure formation of biopolymers with regulation of the contents of ions, and also for reception gels and besieged samples with electroconductivity properties on their basis.
Field of application: dynamics high ordered structure formation of fibrillar proteins in a flow; clcctrophysics polymeric gels and compositions; ions electrodialysis; processing of natural polymers; polarization optics and rheology.

Subject of research: manufacturing of the large size Si(Li) p-i-n and aSi-Si(Li) detector structures.
Purpose of work: investigation the features of formation of the large size high efficiency detector structures with optimal clcctrophysical and radio-metric properties as well as study of new physical mechanisms of influencing for formation their amplitude of energetic spectra.
Methods of research: method of investigation of current-voltage and volt-capacity characteristic of detector structures; method of investigation of features of photovoltagc in nonuniform area of the sensitive regions of Si(Li) p-i-n structure, as well as investigation of the structure research of aSi-Si(Li) interface.
The results obtained and their novelty: physic-technological methods of formation structures with of optimum properties of clectrophysical characteristics and radiometric properties of semiconductor detectors on the base of Si(Li) p-i-n structures and aSi-Si(Li) hcterostucturcs with large area arc developed; on the base of investigation of relaxation photoconductivity processes in Si(Li) p-i-n structure have been carried out that on the some regions of these area was pronounced a “well” on time dependence of photovoltage’s impulse after corresponding photoexcitation is observed; on the basis of analytical calculations of the trajectory of carriers transport in i - area of Si(Li) p-i-n structure where take into account the influence on this process of inhomogeneous potential field it has shown that under such conditions electrons and holes generated as a result of ionization of atoms by nuclear radiation moved forward longer trajectory in electric field direction in sensitive part of semiconductor detector.
Practical value: researched detectors structures Si(Li) p-i-n and aSi-Si(Li) have possess for understanding of physical processes in various large size semiconductor devices as well as practical value for improving of their characteristics.
Degree of embed and economic affectivity: results of investigations had application for optimization of properties of Si(Li) semiconductor detectors at fulfilling contract work with OJSC «UzCRHRM», OJSC «Uzbckchimmash» with total financing around 20 million sum.
Field of application: investigated detector structures have prospects for developing of fundamental and applied problems of nuclear physics.

Subjects of the inquiry: 2,3-tri-,-tetra-,-penta-,-hexamcthylcnc-1,2,3,4-tetrahydroquinazolin-4-oncs.
Aim of the inquiry: reduction of 2,3-polymctylen-3,4-dihydroquinazolin-4-ones by sodium borhydride, systematic study of acylation, carbamoylation, amidomcthylation and clcctrophyl substitution l,2,3,4-tctrahydroquinazolin-4-ones, revealing the optimum conditions reaction. Research of biological activity of synthesized compounds.
Method the inquiry: organic synthesis, IR-, 'H-NMR-spcctroscopy, mass-spectrometry, TLC, X-RAY.
The results achieved and their novelty: reception methods 2,3-polymctylene-l,2,3,4-tctrahcdroquinazolin-4-ones by reduction of 3,4-dihydroquinazolin-4-onc arc improved. It is shown that acylation, carbamoylation, amidomcthylation of them goes on atom of nitrogen N-l, leading corresponding 1-alcyl(aryl)amino(tio)carbamoyl-, -pyrrolidon-2-mcthyl derivatives. It is revealed that in reactions electrophyl substitution at relation 1:1 reaction goes to position C-6, i.e. the normal monosubstituted products arc formed, at relation 1:2 reaction goes unnormal, mentioning positions C-6, C-8 with simultaneous
dehydrogenization -:NH-HC<-bonds, i.e. with formation of-:N=C<-doublc bond.
Practical value: the designed methods of the obtaining 2,3-polymcthylcn-l,2,3,4-tctrahcdroquinazolin-4-ones, their 1-acyl-, -carbamoyl-, -pyrrolidon-2-mcthyl derivatives, as well as 6,8-disubstituted-2,3-polymethylen-3,4-dihydroquinazolin-4-ones, which is difficult to obtain by other methods. It is created way of the syntheses 6-monosubstituted-2,3-polymcthylen-l,2,3,4-tetrahydroquinazolin-4-ones. Amongst synthesized compounds arc revealed biologically active ones.
Degree of embed and economical effectively: amongst synthesized compounds arc revealed compounds, possessing plant growing activity. In future they can find using as stimulators.
Sphere of usage: organic chemistry, agriculture.

Subject of research: the photodiode Au-nAlGaAs-pGaAs-Ag, Au+Zn-p(AlGa)In As-nGaAs-Au, Au-p(A/Ga)InAs-nGaAs-Ag-structurcs, made by a method liquid of epitaxy.
Purpose of work: establishment of a physical nature of processes proceeding in the field of a volumetric charge heterojunction on a basis of arsenide gallium and its connections, and also research of influence of straightening barriers on ampcr's and spectral characteristics of three-barrier structure with various structure hcterowidc.
Methods of research: experimental methods of removal volt-ampcr's, volt -capacitor and spectral characteristics, technique of definition of characteristic parameters on the basis of experimental data.
The results obtained and their novelty:
1. For the first time arc developed multibarrier structures on a basis heterojunction pAlGalnAs-nGaAs and the role of straightening barriers in expansion of a spectral range in area is established.
2. Principles of creation three-barrier photodiode Au-pAlGaInAs-nGaAs:O-Ag-structurcs, quantities,(amounts,) based on a variation, Indium in hcterowidc for various purpose (appointment) for the first time arc offered.
3. Is established, that at excitation Au-pAli)i)SGa()g2^nniAs-nGaAs-Ag-structurc's from the party Ьс1сгослоя the high meanings (importance) of a photocurrent caused fine of area of division of photocarriers and serial compression cuasincytral of a part hcterowidc by a layer of a volumetric charge of locked transitions arc created.
4. Is experimentally shown, that in photodiode to structure the increase of thickness hcterowidc up to the sizes twice large diffusion of length can result in low meanings (importance) of a return current of transition the metal - semiconductor in comparison with a return current heterojunction, that the metal - semiconductor and change of the thermionic mechanism generation is explained by improvement of border.
Practical value: offered in dissertation to job of the recommendation simplify process of the coordination of target parameters of the photoreceiver with entrance parameters of the intensifying cascade photocurrent of devices optoelectronics and systems of telecommunication.
Degree of embed and economic effectivity: the received results arc a basis for development photocurrent of devices for reception and transfer of an optical signal in research-and-production associations Acadcmican sciences of the Republic of Uzbekistan and other instrument-making organizations.
Field of application: technology and designing of the electronic equipment for micro and optoelectmics, and also telecommunication systems, means of transfer and reception of the information.

The relevance and demanding of the subject of the thesis. Today, in the world practice, in the sphere of ensuring the stable operation of electric power systems (EPS), pride of place goes to the creation of high-performance control systems of power generation and consumption processes, involving intelligent technologies. One of the most crucial tasks of rapidly developing modem EPS is ensuring its steady-state stability based on real-time operational data processing and analysis. In this area, the leading countries of the world focus on the improvement of control systems to ensure the stability of electric power systems, taking into account fluctuations of mode parameters. «Expenses for the creation of intelligent electric systems, including Smart Grid, arc as follows: USA - 7.1 trillion, China -7.3 trillion, Japan - 0.8 trillion US dollars. The use of the Smart Grid system in 2020 will allow the USA to save about 1.8 trillion US dollars»1.
Large-scale activities on the effective organization of power generation and improvement of the EPS stability arc held in the Republic of Uzbekistan. A number of research works arc carried out in this area, including high-performance reequipment of the steam-gas and gas-turbine technology, providing electricity generation, the development of effective control system of technological objects and improvement of methods and algorithms of research of control systems.
The world's attention is paid to the development of more advanced methods for determining the stability of electric systems, in particular, matrix methods and algorithms that allow to more deeply explore the modal properties of electric power systems, taking into account modem control devices. The implementation of targeted research is a priority in this field, while researches arc more relevant in the following areas: the development of matrix methods and algorithms for determining the stability of the electric power system based on automatic generator field regulators; the development of simplified criteria for determining the limit mode for the stability of complex EPS; the development of a model of synthesis of automatic field regulators on the basis of the system inclusion technology. Ongoing researches in the above-mentioned areas show the relevance of the subject of this thesis.
This thesis research is designed, to a certain extent, to perform the tasks stipulated in the Decree of the President of the Republic of Uzbekistan ПП-2343 dated 5 May 2015ycar “On the Program of measures to reduce energy consumption, to implement energy saving technologies in the fields of economy and social sphere for 2015-2019 yy.”, in the Decree of Cabinet of Ministers of the Republic of Uzbekistan No.238 dated 13 August 2015 year “On approval of the regulation relating to the republican commission on energy efficiency and development of the renewable energy resources”, as well as other legal documents adopted in this area.
The objective of the research is to develop matrix methods and algorithms of analysis of steady-state stability of complex EPS, to develop simplified methods of estimation of steady-state stability limit and synthesis of controller models based on the systems’ embedding approach.
Scientific innovativeness of the dissertation study consists in the following:
on the basis of Lyapunov’s function in the quadratic form, the simplified criterion of steady-state stability of the electric power system was obtained, which consisted in positivity of the first major minor of the quadratic-form matrix (<7n > 0), ensuring necessary and sufficient conditions of the EPS stability;
the combined use of the method of Lyapunov’s function in the quadratic form and node voltage equations was developed, which allowed for reducing studies of steady-state stability of a complex electric power system to the circuitry of a simple electric power system, or the “generator-bus” system;
a promatrix of the complex unregulated and regulated electric power system was developed on the basis of the system’s embedding method, which allowed for the study of dynamic properties of EPS;
the algorithm of pole transfer from the spectrum of the matrix of own dynamics of the electric power system was developed, which ensured stability and damping of fluctuations of the operation condition parameters at small oscillations in electric power systems;
mathematical model of the class of regulators of the complex electric system was constructed on the basis of the system’s embedding method, which ensured stability and damping of fluctuations of the operation condition parameters at small oscillations in EPS.
CONCLUSION
The theoretical and computational-experimental studies of steady-state stability of complex electric systems, carried out on the basis of the developed matrix methods and algorithms, using Lyapunov’s functions in the quadratic form and system’s embedding method, allow for the following conclusions.
1. Lyapunov’s functions in the quadratic form arc recommended as the effective method for studying the linear dynamic systems, including the electric power system described with the help of linear zed differential equations.
2. Adequacy of conditions of the steady-state stability loss of the electric power system, obtained on the basis of positivity of major minors of the quadratic-form matrix of the Lyapunov’s function in the quadratic from, to the same conditions provided by Hurwitz criteria, was proven.
3. Obtained theoretical and computational results allow one to investigate the stability of EPS “in the small” by means of analysis of the positivity condition of the first major minor of the Lyapunov’s function in the quadratic formq11; > Oand consider it to be the practical (simplified) criterion of steady-state stability of EPS, providing for both its necessary and sufficient conditions.
4. The combined use of Lyapunov’s functions in the quadratic form and nodal equations allows one to reveal the generator (station), operating in the complex EPS, which is coming to the limit in terms of steady-state stability. The mathematical condition of this proposition is dqnj /dFl -» max, i.e. the maximum of the derivative of the first major minor of the quadratic-form matrix by the regulated parameter for the j-th generator. It is evident that in this case, the study of the steady-state stability limit of the complex EPS turns into the study of the “generator-bus” circuit.
5. On the basis of the systems embedding method, promatrices of the unregulated and regulated complex EPS arc developed, which provide a full description of all kinds of characteristics of transitional processes, including the possibility of studying dynamic properties of electric power systems at small oscillations of their operation condition parameters.
6. The model is proposed, in which the regulator of the complex electric power system has been synthesized on the basis of the systems embedding theory to describe analytically the class of regulators ensuring stability and damping of oscillations of the studied EPS.
7. The conducted computational-experimental studies aimed at analysis of steady-state stability of complex EPS on the basis of the systems embedding method have shown the qualitative match of the obtained results with the results, checked in the course of practical running of electric power systems on the basis of Classical Methods that confirms the adequacy of the models developed to the already existing ones.
8. The mathematical model of the electric power system, resolved relative to deviations of absolute angles of synchronous generators, is developed, which can be used autonomously for the study of small oscillations of complex EPS. This model of small oscillations must be used together with node voltage equations, determining voltage modules of nodes and their arguments, representing absolute angles relative to the balancing node.

The aim of research work is elaboration of electrochemical sensors and their application at analysis of cadmium, indium and antimony.
The object of the research work. Various metals, alloys, solders, lubricants, ores, minerals, waters of different nature and standard samples.
Scientific novelty' of the research w ork is as follows:
for the first time the optimal compositions and ratio of components of buffer mixtures and phone electrolytes have been determined;
influens of potential, time of depolyarizator accumulation on electrodes, temperature of investigated solution and diapason of current on the value of useful analytical signal was investigated;
influence of strange accompaning cations, complex-forming compounds and advisable anions on the results of selective inversion voltamperometrical determination of investigated metals in real natural objects and industrial materials has been investigated;
investigation of Hg(II) on the analytical signal of determined metals was shown and also their hybrid extraction inversion voltamperometrical determination was carried out;
Implementation of the research results.
Elaborated inversion voltamperometrical determination of investigation metals were recommended for testing and following introduction of analysis;
inversion voltamerometrical methods of determination of microquantities of ions of Cd, In and Sb were introduced in practices of chemical-analytical laboratories «Dehkanabad potash plant» (certificate from 11 September 2017 year №782/09-3) «Dehkanabad potash plant». Positive results by determination of heavy metals with using of electrochemical sensors modified by some organical reagents were obtained;
On introduction of inversion voltamperometry at determination ions of In, Cd and Sb there are certificate from center of controle of sanitarial-epidemiological service of Republic of Uzbekistan (from 15 September 2017 year №16-8/6790).
The structure and volume of the thesis. The thesis consisted from introduction, five chapters, conclusion, list of used literature and, supplement. Volume of dissertation is 120 pages.

The aim of research work is investigation of processes of formation by the Solgel technology of sensor elements based on thin films of composition SiO2/TiO2, and also elaboration of selective semiconductor gas sensors for determination of NH3 concentrations with using of nanomaterials obtained by Sol-gel process.
The object of the research work. Oxides of metals (Ti, Zn, Fe etc.), the exhaust gases of the enterprises producing mineral fertilizers, ammonia and standard gas mixtures were objects of this investigation.
Scientific novelty of the research work is as follows:
the scientifically novelty of investigation is conceding in following for the first time by using sol-gel technology on the basis of TiO2 and Fe2O3 synthesis of selective GSM for determination of NH3 in mixtures of gases was carried out.
it is shown that modification by oxides of Fe gas-sensitive nanocomposites on the baze of SiO2-TiO2 has leaded to decreasing of temperature sensitivity and increasing of selectivity PPP by NH3.
with the application of selected catalysts and optimal parameters the high sensitivity of determination of NH3 in the presence of H2, CO and CH4 has been ensured.
selectivity of semiconductor determination of NH3 based on the use of gassensitive materials containing catalysts possessed by inadequate activity to the components of the gas mixture has been provided;
the influence of various factors on the metrological, operational and other parameters of PPS-NH3 on the base of 5% Fe2O3-95% TiO2 was determined.
Implementation of the research results.
The results of scientific research works by elaboration of highly effective sensors on ammonia were used in University of Vienna Institut fur Physikalische Chemie in the research project "Composite materials for chemical sensing" (certificate of the University of Vienna from 21 December 2016). The results of investigation were at elaborated used of chemical sensors; study the dynamic, al calibration characteristics of the sensors on NH3, and development of chemical and physico-chemical methods of determination of toxic gases.
PPS obtained in the result of elaboration of selective gas sensitive material have been used in a research grant, F-7-06 "Investigation of the theoretical bases of using of nitrogen - and phosphorus-containing compounds as inhibitors of burning of inflammable materials" (SSU 2012-2.16). With using of the elaborated sensors the influence of nitrogen - and phosphorus-containing antiperences on the kinetics and the mechanism of slowing the combustion process and also density of the textile materials on the rate of flame distribution (certificate FTK-0313/703 of Committee by coordination of development of science and technology dated 14 February 2017).
The structure and volume of the thesis.
The thesis consists from introduction, five chapters, conclusion, bibliography and applications. The volume of the dissertation is 120 pages.

The aim of the research is design of sophisticated algorithms for choosing Ground Wires on multi-wire Overhead Power Transmission Lincs, which allow to take into account parameters along the whole length of the line
Scientific novelty of the research is consisted of the following:
dependence of calculated values of currents in wires at asymmetrical short circuit modes on parameters of multi-wire Overhead Power Transmission Lines (tower geometry, span length, types of phase and ground wires) on the basis of the use of sparse matrices was determined;
equivalent resistances of Ground Wires on Overhead Power Transmission Lines with taking into account tower total grounding resistances were improved;
algorithm for thermal stability calculations of Ground Wires to asymmetrical short circuit currents on the base of presenting Overhead Power Transmission Lines as multi-wire system was improved;
possibility of reducing current levels in Ground Wires with embedded Optical Cables at asymmetrical faults on the base of tower grounding resistance insulations made on substations was developed.

The aim of the research is working out methods and facilities for providing indicators of electricity quality at steady-state asymmetric modes in low-voltage electrical power grids
Scientific novelty of the research is as following:
development of a method for estimating additional losses in the case of longitudinal and cross asymmetry in low-voltage electrical networks;
there has been worked out the construction of electromagnetic converter of three-phase asymmetrical current into voltage;
there has been worked out the method for providing quality of electricity with the use of electromagnetic converter of three-phase asymmetrical current into voltage;
there has been designed a device “Malika-01” assigned for measuring indicators of electricity quality in low voltage electrical power grids has been designed.