38 research outputs found
CLINICAL VALUE OF MULTISLICE SPIRAL X-RAY COMPUTED TOMOGRAPHY WHEN PLANNING THE TREATMENT OF PATIENTS WITH LARYNGEAL CANCER
Cancers remain a priority for modern society. According to the WHO estimates, global cancer morbidity and mortality rates will triple in the period 1999 to 2030: from 10 to 30 million new cases and from 6 to 17 million deaths recorded every year, which will exceed deaths from cardiovascular diseases and injuries. The efficiency of treatment in cancer patients and their prediction are determined by timely disease diagnosis, tumor extent estimation, and adequate therapeutic measures. So search for ways to cardinally improve the early recognition of cancer is one of the major tasks in the study of the problems of cancer patients, those with throat cancer in particular
Optimisation and characterisation of durable microelectrodes for electroanalysis in molten salt
This work presents microfabricated microelectrodes, capable of quantitative analysis in
molten salt (MS). MSs are an electrolytic medium of growing interest, especially in the
area of nuclear reprocessing. However, designing sensors for a MS-based nuclear reprocessing
system is a challenge, owing to the usually corrosive nature and high operating
temperatures (typically 450 - 500◦C) of MS.
Microelectrodes are well placed as sensors, with numerous advantages over macro-scale
electrodes. As a consequence, there have been previous attempts to utilise microelectrodes
inMS. However, these have not been successful and all have suffered disadvantages
inherent in traditional microelectrode manufacturing.
The microelectrodes presented in this work were produced using standard microfabrication
techniques and characterised in MS. An analysis of failure mechanisms guided a
systematic study of material combinations. This resulted in a sensor, which is capable
of delivering quantifiable electrochemistry in MS. However, the lifetime and yield of the
sensor were determined to only be 46% and 1.4 hours respectively.
Further investigation of the microelectrode failure mechanisms guided several layout
changes to the microelectrode design. By reducing critical area, where defects or pinholes
could form, these resulted in improvements in performance. This increased the yield to
65%, while the average lifetime increased up to 45 hours.
Test structures were designed to investigate the causes of the continued microelectrode
failures and identified shorting between the electrode metal and silicon substrate. This
suggests the existence of defects in the underlying insulator are the cause of the 35%
of microelectrodes which never functioned. Separate test structures suggested the lifetimes
of the microelectrodes could also be improved by removing the need for a metal
adhesion layer. Tantalum has been suggested as a replacement electrode metal and a
proof of concept study demonstrated the feasibility of employing thin film tantalum as
an electrode metal in LKE.
Using this technology as a platform, several proof-of-concept microelectrode designs
are also presented: liquid microelectrodes, microelectrode arrays, and a nanoelectrode.
These are targeted at specific sensing applications, and provide an expanded spectrum
of measurements in MS
ChemInform Abstract: High-Temperature Electrochemical Synthesis of Tungsten and Molybdenum Borides in Ionic Melts.
Electrochemical Synthesis of Double Molybdenum Carbides
Written to record and report on recent research progresses in the field of molten salts, Molten Salts Chemistry and Technology focuses on molten salts and ionic liquids for sustainable supply and application of materials. Including coverage of molten salt reactors, electrodeposition, aluminium electrolysis, electrochemistry, and electrowinning, the text provides researchers and postgraduate students with applications include energy conversion (solar cells and fuel cells), heat storage, green solvents, metallurgy, nuclear industry, pharmaceutics and biotechnology
Peculiarities of Holmium and Iron Triad Ions Co-Reduction: Formation of HoxNiy (HoxCoy, HoxFey) Intermetallic Compounds in Chloride Melts
The present paper is focused on the analysis of Ni2+, Co2+, Fe3+, and Ho3+ ion co-reduction in the background equimolar NaCl-KCl melt at 973 K using the method of cyclic voltammetry. It was found that the co-reduction potentials of Ho3+ and iron triad ions differ greatly. The depolarization of metallic holmium electrodeposition on one of the iron triad metals preliminary deposited on the tungsten electrode was determined. This process resulted in the formation of the HoxNiy, HoxCoy, and HoxFey intermetallic compounds. It was observed that the HoxNiy, HoxCoy, and HoxFey intermetallic compounds may be synthesized in a kinetic regime. The influence of the current density, electrolytic bath composition, and electrolysis time on the composition of the obtained intermetallic compounds was studied. The possibility of synthesizing cathode deposits composed solely of intermetallic compounds is verified. It is demonstrated that the intermetallic compounds may be formed by the addition of the iron triad metals (in particular, metallic iron) via anode dissolution. Synthesized HoxNiy, HoxCoy, and HoxFey samples were characterized by X-ray diffraction analysis, scanning electron microscopy, and photon correlation spectroscopy
Productivity of sudan grass and sorghum-sudangrass hybrids depending on seeding rates and planting methods in the steppe dryland zone of the Kabardino-Balkarian Republic
The article contains the results of three-year field research in the steppe dryland zone of the republic, the best options of grass sorghum cultivation, which increase the gross yield of green forage and hay were developed. Optimum planting standards for dry steppe conditions, planting and harvesting methods of Sudan grass and sorghum-Sudangrass hybrids were identified to produce a high, more energy-intensive green and dry forage of the studied crops. The quality and feed qualities of fodder for production and direct feeding to animals are determined. The crop growing time after hay harvest and quantity for feeding after harvesting are given
Mechanism of Dy3+ and Nd3+ Ions Electrochemical Coreduction with Ni2+, Co2+, and Fe3+ Ions in Chloride Melts
The present paper is devoted to the study of the processes of the mechanism of electrochemical coreduction of Dy3+ and Nd3+ ions with Ni2+, Co2+, and Fe3+ ions in the equimolar NaCl-KCl melt at 973 K and characterization of the synthesized samples. The performed voltammetry analysis of the electrochemical coreduction processes elucidated a significant difference in the values of the extraction potentials of the studied metals. This melt testifies that intermetallic compounds of Dy and Nd with Ni, Co, and Fe may be synthesized in the kinetic regime. The intermetallic phases of Dy and Nd with Ni, Co, and Fe are found to be formed along with the phases of metallic Ni, Co, and Fe either during electrolysis at the cathode current densities exceeding the limiting diffusion current of Ni2+, Co2+, and Fe3+ ions or in the potentiostatic regime at the potentials of the corresponding voltammetry curves. Therefore, the following interrelated key parameters affecting the electrochemical synthesis of Dy and Nd intermetallic compounds with Ni, Co, and Fe were determined: (i) composition of the electrolyte, i.e., concentrations of FeCl3, CoCl2, NiCl2, DyCl3, and NdCl3; (ii) cathode current density or electrolysis potential and (iii) electrolysis time. The obtained samples were characterized by micro-X-ray diffraction analysis, cyclic voltammetry, and scanning electron microscopy methods
ON THE ROLE OF REGIONAL UNIVERSITIES IN THE DEVELOPMENT OF SCIENCE AND EDUCATION
We discuss the role of regional universities in the development of physical-chemical research and education on the example of Kabardino-Balkarian State University (KBSU). Special attention is paid to the development of scientific schools in physics and chemistry. The authors dwell on the prehistory of the development of natural sciences in KBSU during the Soviet period and the most important achievements of the past two decades in such fields as fluctuational electrodynamics, electrochemistry, nanochemistry, high molecular chemistry