Tetramethylsilane Research Articles

SiCN:H thin films deposited by MW‐PECVD with liquid organosilicon precursor: Gas ratio influence versus properties of the deposits

AbstractSilicon carbonitride SiCN:H thin films are deposited with microwave plasma‐enhanced chemical vapor deposition. Argon, ammonia, and tetramethylsilane (TMS) (Ar/NH3/Si(CH3)4) are used for the gas mixture. Plasma gas phase chemistry is studied using optical emission spectroscopy according to the TMS/NH3 gas flow ratio, highlighting the presence of three discharge regimes. Then, the deposited SiCN:H thin films are analyzed by X‐ray photoelectron spectroscopy and energy dispersive X‐ray spectroscopy, enabling us to correlate plasma and film chemistry. Thus, we define three thin film families corresponding to the three discharge regimes occurring in the plasma phase. Properties of these families are studied: Optical properties by spectroscopic ellipsometry, electrical properties by I–V measurements and electron spin resonance, and mechanical properties by nanoindentation and tribology.

Processing Techniques for Scanning Electron Microscopy Imaging of Giant Cells from Giant Cell Tumors of Bone.

Giant cell tumor (GCT) of bone is a common benign lesion that causes significant morbidity due to the failure of modern medical and surgical treatment. Surface ultra-structures of giant cells (GCs) may help in distinguishing aggressive tumors from indolent GC lesions. This study aimed to standardize scanning electron microscopic (SEM) imaging of GC from GCT of bone. Fresh GCT collected in Dulbecco's Modified Eagle Medium was washed to remove blood, homogenized, or treated with collagenase to isolate the GCs. Mechanically homogenized and collagenase-digested GCs were imaged on SEM after commonly used drying methodologies such as air-drying, tetramethylsilane (TMS)-drying, freeze-drying, and critical point-drying (CPD) for the optimization of sample processing. The collagenase-treated samples yielded a greater number of isolated GC and showed better surface morphology in comparison to mechanical homogenization. Air-drying was associated with marked cell shrinkage, and freeze-dried samples showed severe cell damage. TMS methodology partially preserved the cell contour and surface structures, although the cell shape was distorted. GC images with optimum surface morphology including membrane folding and microvesicular structures on the surface were observed only in collagenase-treated and critical point-dried samples. Collagenase digestion and critical point/TMS-drying should be performed for optimal SEM imaging of individual GCs.

Reprint of “Improvement of mechanical strength of hydrophobic coating on glass surfaces by an atmospheric pressure plasma jet”

Non-thermal plasma is getting more popular in industrial applications, mainly treatment of material surfaces. Hydrophobic coatings often suffer mechanical instability and do not function well after abrasion/scratching. In this study, non-thermal plasma jet generated at atmospheric pressure in ambient condition was applied to the hydrophobic treatment of glass surface using two precursors. Tetramethylsilane (TMS) was used to promote hydrophobicity and (3-Aminopropyl)triethoxysilane (APTES) was used to get durable mechanical strength of the coating although it is hydrophilic in character. An alternating current (AC) high voltage (operating frequency: 11.5 kHz) was used to generate plasma jet for producing a coating layer onto the soda-lime glass sample. Water contact angle of 139° and a stable mechanical strength were achieved at an optimal TMS/APTES ratio of 4.8. The coating thickness, strength and water contact angle were varied by changing treatment time, applied voltage, and carrier gas (argon) flow rate. The coating layer were characterized by atomic-force microscopy (AFM), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), water contact angle (WCA), scratch test and UV/visible spectroscopy.

Correction for volume recombination in liquid ionization chambers at high dose-per-pulse.

To determine the volume recombination at high dose-per-pulse in liquid ionization chambers (LIC) and to ascertain whether existing calculation methods verified in air-filled chambers may be used to calculate a correction factor. Two LICs, one filled with 2,2,4-trimethylpentane (isooctane) the other with tetramethylsilane (TMS), were irradiated in a pulsed, 20MeV electron beam. Via reference measurements with a Faraday cup, the saturation correction for volume recombination was determined for dose-per-pulse values ranging from about 5mGy to 1Gy for both chambers at a pulse duration of 693ns. In addition, the isooctane chamber was irradiated with pulses of varying duration, ranging from 5ps to 10ms, at a dose-per-pulse of about 76.5mGy. The dose-per-pulse-dependent measurements were compared to calculations based on Boag's models (with and without a free electron fraction), the two-dose-rate method, and a numerical calculation. The pulse duration dependent measurements were compared only to a numerical calculation that iteratively calculates the charge transport and loss in a 1D model of an ionization chamber. In TMS only Boag's model with a free electron fraction and the numerical calculation are in good agreement with the experimental data. However, in isooctane, good agreement is observed between the experimental data, the numerical calculation as well as the two-dose-rate method, and Boag's model including a free electron fraction. Only Boag's model without a free electron fraction shows a good agreement with lesser extend. Furthermore, the pulse duration-dependent data for isooctane are well described by the numerical model. With isooctane as an active medium, a LIC could be directly used in a field with high dose-per-pulse utilizing the well-established two-dose-rate method to correct the volume recombination. In addition, pulsed fields with variable pulse duration are easily modeled for this medium using a numerical calculation. Other media, as exemplified by the TMS-filled chamber, might require additional considerations, such as including a fraction of free electrons in the consideration of volume recombination.

High-rate, room-temperature synthesis of amorphous silicon carbide films from organo-silicon in high-density helicon wave plasma

In this study, amorphous silicon carbide (α-SiC) films were synthesized on 316L stainless steel by low pressure, high density helicon wave plasma (HWP), using tetramethylsilane (TMS) as the single-source precursor which is organometallic compound. The influence of the substrate bias voltage (Vs) on the surface morphology, structure, chemical composition, and mechanical properties of the α-SiC films is investigated. The increase of VS from 0 to 200 V causes the removal of organic moieties from the film and results in the formation condition for α-SiC. The maximum deposition rate of the coating is up to 250 nm/s, which is related to the high-density (>1019 m−3) plasma production of HWP [1]. The X-ray photoelectron spectroscopy (XPS) and Fourier Transform Infrared Spectrometer (FTIR) results imply that the film is mainly composed of SiC. The films deposited at VS = 200 V appear to be high-hardness (up to 33.6 GPa) materials with very small surface roughness (∼0.5 nm). Considering the easy control of the bias voltage, our work provides a new method for achieving α-SiC films with high-yield at room temperature.

The synthesis and the study of the antitumor activity of 1,4-diaryl-5,6,7,8-tetrahydro-2,2a,8a triazacyclopenta[cd]azulene derivatives

Aim. To synthesize, prove the structural framework and study the antitumor activity of 1,4-diaryl-5,6,7,8-tetrahydro-2,2a,8a-triazacyclopenta [cd]azulene derivatives.Results and discussion. To determine the antineoplastic activity of 1-phenyl-4-aryl-5,6,7,8-tetrahydro-2,2a,8a-triazacyclopenta[cd]azulenes 7a-g and 1-(41-bromophenyl)-4-aryl-5,6,7,8-tetra-hydro-2,2a,8a-triazacyclopenta [cd]azulenes 7h-k the study in vitro was carried out on 60 lines of cancer cells (leukemia, non-small cell lung cancer, colon cancer, CNS cancer, melanoma, ovarian cancer, renal cancer, prostate cancer and breast cancer) under the effect of the substance in the concentration of 10-5 mol/l according to the standard procedure of the mitotic activity assessment of the new potential bioactive compounds by the fluorescent coloring method (sulphorhodamine B as a dye) performed in the US National Institute of cancer within the Development Therapeutic Program.Experimental part. 2-Methoxy-3,4,5,6-tetrahydro-7H-azepine was obtained by alkylation of caprolactam with dimethyl sulfate. 3-Phenyl or (41-bromophenyl)-(6,7,8,9-tetrahydro-5H-[1,2,4]triazolo[4,3-a]azepine 4 a,b was obtained by condensation of 2-methoxy-3,4,5,6-tetrahydro-7H-azepine 1 with 4-bromobenzoic acid hydrazide and subsequent cyclization of the intermediate product. The 1Н-NMR spectra were recorded on a Bruker VXR-300 spectrometer (Germany) with the working frequency of 299.945 MHz, in DMSO-d6 using tetramethylsilane (TMS) as an internal standard. The purity of the compounds synthesized was controlled by TLC on the Silufol UV-254 plates in the system of chloroform – methanol (9 : 1). Conclusions. New chemical compounds – derivatives of 1-phenyl(41-bromphenyl)-4-aryl-5,6,7,8-tetrahydro-2,2a,8a-triaza-cyclopenta[cd]azulene have been synthesized. The anticancer activity of the compounds obtained on 60 lines of tumor cells in the US National Cancer Institute has been studied. The high-active compounds that exhibit high levels of the antitumor activity have been identified.

Formation of plasma-polymerized superhydrophobic coating using an atmospheric-pressure plasma jet

The conditions for the deposition of stable superhydrophobic coatings on glass substrates using a dielectric barrier discharge plasma jet with tetramethylsilane (TMS) and 3-aminopropyl(diethoxy)methylsilane (APDMES) as precursors were investigated. The coatings, which were formed under different plasma conditions, were characterized by various methods including atomic force microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, static water contact angle (WCA) and sliding angle measurement, and a scratch test. The results presented that superhydrophobic and mechanically stable plasma coatings could be obtained by optimizing the treatment time, applied voltage, gas flow rate into the plasma chamber, and APDMES/TMS ratio. The results indicated that the use of TMS on its own as the coating precursor led to the formation of unstable coatings. However, the mechanical stability increased significantly when APDMES and TMS were used in combination. As a result, a durable coating layer with a WCA of 163° and sliding angle of 3° was achieved for an APDMES/TMS ratio of 1.7.

Structural, vibrational, spectroscopic, NMR and quantum chemical studies on fullerene and bromofullerenes

The most stable, optimized structures of fullerene (C60) and bromofullerenes (C60Br6) molecules were predicted by the density functional theory calculations using B3LYP method with 6311G(d,p) basis set. The obtained parameters were estimated by density functional theory (DFT) and time-dependent density functional theory (TD-DFT). Bromofullerene (C60Br6) was architectured by directly bonding with bromine atom at C60 reactive sites. Theoretically calculated vibrational wavenumbers were assigned and compared. Ultraviolet–visible spectrum was mimicked by Polarizable Continuum model. The 13C NMR spectra were simulated by nuclear magnetic tensor GIAO for C60 and C60Br6 relative to tetramethyl silane. The molecular electrostatic potential surface was simulated. The transition between highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) revealed different charge transfer possibilities which occur for the molecule and other related molecular properties were computed and tabulated. Natural bond orbital (NBO) analysis was carried out to image the charge transfer between the localized bonds and lone pairs of the electrons. The enhanced reactivity and peculiar energy gap by the substitution of bromine in fullerene pave way for designing the optoelectronic devices and bioactive molecules which will be useful in the field of sensors and carbon nano medicine.

Improvement of mechanical strength of hydrophobic coating on glass surfaces by an atmospheric pressure plasma jet

Non-thermal plasma is getting more popular in industrial applications, mainly treatment of material surfaces. Hydrophobic coatings often suffer mechanical instability and do not function well after abrasion/scratching. In this study, non-thermal plasma jet generated at atmospheric pressure in ambient condition was applied to the hydrophobic treatment of glass surface using two precursors. Tetramethylsilane (TMS) was used to promote hydrophobicity and (3-Aminopropyl)triethoxysilane (APTES) was used to get durable mechanical strength of the coating although it is hydrophilic in character. An alternating current (AC) high voltage (operating frequency: 11.5 kHz) was used to generate plasma jet for producing a coating layer onto the soda-lime glass sample. Water contact angle of 139° and a stable mechanical strength were achieved at an optimal TMS/APTES ratio of 4.8. The coating thickness, strength and water contact angle were varied by changing treatment time, applied voltage, and carrier gas (argon) flow rate. The coating layer were characterized by atomic-force microscopy (AFM), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), water contact angle (WCA), scratch test and UV/visible spectroscopy.

Adhesion and durability of multi-interlayered diamond-like carbon films deposited on aluminum alloy

Aluminum (Al) alloys are light and have good workability; however their low hardness and poor wear resistance are drawbacks limiting their wide application in the automotive industry. Deposition of diamond-like carbon (DLC) films, which exhibit high hardness and good wear resistance, onto the surface of Al alloy substrates can overcome these drawbacks. Because Al alloys and DLC films have low affinity for each other, adhesion between the two is poor. However, the use of an interlayer can improve adhesion. To investigate the effect of multi-interlayers on the adhesion and durability of DLC films on Al substrates, DLC films with Ti, Si-DLC, or Ti/Si-DLC interlayers were deposited onto A2024 substrates using plasma-enhanced chemical vapor deposition (PECVD). Prior to PECVD, an Ar-bombardment treatment was conducted to clean the surface of the substrate. Subsequently, a Ti interlayer was deposited by sputtering for 15 min, a Si-DLC interlayer was deposited using a tetramethylsilane (TMS) and methane gas mixture for 15 min, and DLC was deposited using methane gas for 90 min. The nanohardness of the Ti/Si-DLC multi-interlayered sample reached 33 GPa more than 8 GPa higher than that of the single-interlayered samples. In addition, the Ti/Si-DLC multi-interlayered sample exhibited higher hardness/Young's modulus (H/E) ratios than the single-interlayered samples. Wear tests showed that the wear volumes for the balls and the multi-interlayered samples were smaller than those for the single-interlayered samples. In addition, the delamination distance of the Ti/Si-DLC multi-interlayer sample was 3300 m, more than 1500 m longer than that of single-interlayered samples. This study demonstrates that improving the wear resistance required high plastic index parameter (H/E) values rather than high H values.

Synthesis and physical-chemical properties of some 5-(3-fluorophenyl)-4-methyl-1,2,4-triazole-3-thiol derivatives

There are engaged scientists practically from all over the world to the 1,2,4-triazole system research but the greatest attention deserve the achievements of domestic scientists who managed from the very beginning to register new original medicines in Ukraine. There is no doubt that the original attempt of combining various typical fragments with the nucleus of 1,2,4-triazole is gaining popularity among researchers.
 The purpose of our work was to synthesized and investigate a row of new 5-(3-fluorophenyl)-4-methyl-1,2,4-triazole-3-thiols by a Sulfur atom, to study the physical-chemical properties of previously unsubscribed compounds.
 The chemical names of the compounds are given in accordance with the IUPAC nomenclature (1979) and the IUPAC recommendations (1993). Investigations of the physical-chemical properties of the obtained compounds were carried out according to the methods which are given in the State Pharmacopoeia of Ukraine. The melting point was determined on an automatic device for determining the melting point OptiMelt Stanford Research Systems MPA100 (USA). The elemental structure of the new compounds was established on the element analyzer Elementar Vario L cube (CHNS) (standard - sulfanilamide). The data of elemental analysis correspond to the calculated. The 1Н NMR-spectra of the compounds were recorded using a «Mercury 400» spectrometer, the solvent DMSO-d6, the internal standard – tetramethylsilane (TMS) and decrypted using the SpinWorks computer program. Chromate-mass spectra were recorded on an Agilent 6890N/5973N/FID spectrometer produced by Agilent Technologies with a Dean microflow switch.
 By the experiment results there were obtained eleven previously unidentified individual compounds light yellow and white color which are soluble in organic solvents and insoluble in water. The crystallization process was carried out in isopropanol.
 Using a complex approach with the use of modern physical-chemical methods of analysis we confirmed the structure of 5-(3-fluorophenyl)-4-methyl-1,2,4-triazole-3-thiol, 3-alkylthio-5-(3-fluorophenyl)-4-methyl-1,2,4-triazole, 1,4-bis((5-(3-fluorophenyl)-4-methyl-1,2,4-triazole-3-yl)thio)propane and 1,4-bis((5-(3-fluorophenyl)-4-methyl-1,2,4-triazole-3-yl)thio)butane.
 The individuality of the synthesized compounds was confirmed chromatographically, the constants peaks of the pseudo molecular ions of the synthesized compounds coincide with the calculated values of the molecular masses.
 We first synthesized 5-(3-fluorophenyl)-4-methyl-1,2,4-triazol-3-thiol which was further used as a starting material in the synthesis of new 3-alkylthio-5-(3-fluorophenyl)-4-methyl-1,2,4-triazole, 1,4-bis((5-(3-fluorophenyl)-4-methyl-1,2,4-triazol-3-yl)thio)propane and 1,4-bis((5-(3-fluorophenyl)-4-methyl-1,2,4-triazol-3-yl)thio)butane. Complex physical-chemical methods of analysis confirmed the structure of synthesized compounds.

Comparative study of flame-based SiO2 nanoparticle synthesis from TMS and HMDSO: SiO-LIF concentration measurement and detailed simulation

Depending on the chemical nature of precursor species, the flame-based synthesis of silicon dioxide nanoparticles in lean hydrogen/oxygen flames proceeds via different chemical routes, which affects the generated particle characteristics. Modeling the flame chemistry and particle formation therefore can provide valuable understanding of the underlying gas-phase and particle-formation pathways. In the present study we compare experimentally obtained temperature and semi-quantified SiO-concentration profiles in low-pressure (3 kPa), lean (ϕ < 0.6), inert-gas diluted H2/O2/Ar burner-stabilized flat flames doped with 200–4000 ppm hexamethyldisiloxane (HMDSO) or tetramethylsilane (TMS) with results from kinetics modeling. Temperature fields in the flames were determined via multi-line laser-induced fluorescence (LIF) imaging using both added NO and native SiO as target species. Gas-phase silicon monoxide (SiO) was detected via LIF by exciting the rovibrational Q(42) transition in the A1Π–X1Σ+ (1,0) vibronic band system at 230.998 nm that provides a weak temperature dependence when analyzing relative SiO mole fractions. Semi-quantitative SiO mole-fraction profiles as a function of height-above-burner (HAB) were obtained for all flames from the measured SiO-LIF intensities corrected for variations of the temperature-dependent ground-state population and the collisional quenching using measured temperatures and effective fluorescence lifetimes, respectively. The experimental data were compared with results of appropriate chemical kinetics mechanisms from the literature with suitable modifications to best reproduce measured SiO mole-fraction profiles. Modeling initial cluster formation is important in this study to unravel the observed ‘double-peak’-structure of the SiO concentration profiles assumed to originate from resublimed SiO from early-formed SiO2 nanoparticles in the rising temperature gradient during initial particle nucleation, and which may be altered by the availability of oxygen in the precursor species.

Near‐field scanning microscopy and physico‐chemical analysis versus time of SiCN:H thin films grown in Ar/NH3/TMS gas mixture using MW‐Plasma CVD at 400 °C

Silicon carbonitride thin films (a‐SiCN:H) are deposited by means of microwave plasma enhanced chemical vapor deposition with argon, ammonia and TetraMethylSilane (TMS). Morphological studies are realized using Atomic Force Microscopy (AFM) and different deposition times are compared for two gas mixture ratios. Abbott‐Firestone curves and the ratio “projected area to developed area” studies allow us to attribute films growth in this process to Volmer‐Weber mode. These results are correlated to thin films compositions: Fourier Transform Infrared Spectroscopy (entire thickness of films), and X‐ray Photoelectron Spectroscopy (extreme surface). Extreme surface composition does not vary versus deposition time according to plasma composition. However bulk composition of the deposited films varies due to heating of the substrate along the deposition process.

Pulsed X-Ray Source (PXS) for Calibrating Microdosimeters Based on “Warm Liquids” and Testings of Television Type Detectors

The PXS is developed for calibrating microdosimeters and testing television-type detectors (TVTDs) and quality check of tetramethylsilane (TMS) samples after purification from electronegative impurities. The PXS design and block diagram are described. The pulsed X-ray source based on a solid-state discharger with an advanced system for triggering the controlled discharger and external devices, which have minimum noise characteristics, is described.

Tetramethysilane-assisted enhancement of diamond nucleation on silicon substrate

This paper describes the effect of tetramethylsilane (TMS) on diamond nucleation on Si substrate under an applied bias voltage of 120 V, performed in a modified microwave plasma chemical vapor deposition (MPCVD) reactor. The introduction of TMS in the CH4/H2 plasma leads to a significant enhancement of nucleation density of diamond nuclei, namely from (3.7 ± 0.2) × 107/cm2 without the introduction of TMS to (4.7 ± 0.5) × 1010/cm2 at the TMS flow rate of 4 sccm. On the contrary, further increasing in the TMS flow rate to 8 sccm slightly reduces the nucleation density of diamond nuclei to (2.1 ± 0.3) × 1010/cm2, along with the increase in average size of diamond nuclei. High-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) allow us to study the microstructural and chemical composition evolution of Si/diamond interface. The obtained results suggest that bias-enhanced nucleation of diamond on Si substrate exhibits a direct relationship with the TMS flow rate.

Silicon nitride cover layer prepared by silane-free plasma chemical vapor deposition for high quality surface passivation of silicon solar cells

Passivated emitter and rear contact (PERC) silicon solar cell is one of the most promising high-efficiency solar cells, which uses aluminum oxide (Al2O3) and hydrogenated silicon nitride (SiNx:H) stack as the rear passivation layer. The SiNx:H not only serves as a protective layer but can provide hydrogen atoms that further passivate the dangling bonds on silicon wafer surface. In this study, the SiNx:H cover layers are deposited using high density plasma chemical vapor deposition with a silane-free gas mixture of tetramethylsilane (TMS) and ammonia (NH3). Effects of the TMS gas flow rate on properties of the SiNx:H cover layers and effective minority carrier lifetime of silicon wafers are investigated. The experimental results show that the film density is positively related to the SiN bond proportion. The secondary ion mass spectrometry measurement shows that the dense SiNx:H can make hydrogen atoms move toward wafer surface instead of out-diffusion to the environment. The best SiNx:H film is deposited at a TMS flow rate of 35 sccm. The minority carrier lifetime can be improved from 70 μs for as-cleaned wafer to 373 μs for wafer/Al2O3 and to 1006 μs for wafer/Al2O3/SiNx:H. The surface recombination rate of 23 cm/s is obtained. Therefore, this study demonstrates the dense, silane-free SiNx:H films with high passivation quality for PERC solar cells.

Synthesis and structure of some new Schiff bases, derivatives of 2-((4-((R-benzylidene)amino)-5-(2-fluorophenyl)-4H-1,2,4-triazole-3-yl)thio)acetohydrazides

Triazole derivatives are among wide range of pharmacological agents, such as antimicrobial, analgesic, anti-inflammatory, anticonvulsant, antitumor, antimalarial, antiviral, antiproliferative, anti-cancer drugs etc. The importance of triazole derivatives is in their various biological properties. That is why they have a good position in heterocyclic chemistry. The purpose of this work was to synthesize and define physical and chemical parameters of new 2-((4-((R-benzylidene)amino)-5-(2-fluorophenyl)-4H-1,2,4-triazole-3-yl)thio)acetohydrazide derivatives. Material and methods. Studying of physical and chemical properties of synthesized compounds was carried out in accordance with the methods of the State Pharmacopoeia of Ukraine. The melting temperature of the synthesized compounds was set on the automatic device for determining the melting temperature MPA100. The Elementar Vario L cube element element analyzer was used to determine the elemental composition of the synthesized substances. 1 H NMR spectra of compounds were recorded using a Varian Mercury VX-200 spectrometer ( 1 H, 200 MHz), solvent ­ DMSO- d6 , internal standard ­ tetramethylsilane (TMS). Results. 2-((4-((R-benzylidene)amino)-5-(2-fluorophenyl)-4H-1,2,4-triazole-3-yl)thio)acetohydrazides (1a-c) were used as initial materials. These compounds were obtained by reaction of hydrazine hydrate 1.5 molar excess with the corresponding 2-((4-((4-R-benzylidene)amino)-5-(2-fluorophenyl)-4H-1,2,4-triazole-3-yl)thio)acetic acid. Subsequently, corresponding R'-benzaldehyde was added to the synthesized products 1 a-c in the mixture of acetic acid-isopropyl alcohol (2: 1) and heated for 30 minutes, after which the final product was isolated after 6-8 hours. Conclusions. As a result of the research 18 new 2-((4-((R-benzylidene)amino)-5-(2-fluorophenyl)-4H-1,2,4-triazole-3-yl)thio)acetohydrazides (1a-c) and their R'-N-benzylidene-2-((4-((4-R-benzylidene)amino)-5-(2-fluorophenyl)-4H-1,2,4-triazole-3-yl)thio)acetohydrazides (2a-e, 3a-h, 4a, 4b) were synthesized. The structure of the obtained substances was confirmed by the data of elemental analysis, 1 H NMR spectroscopy.

Development of Microdosimeters for Beam Therapy Based on Superpure Tetramethylsilane and Testing of its Conductivity

A setup version for producing samples of tetramethylsilane (TMS) and its cleaning from electronegative impurities is developed and tested. Purified TMS can be used in microdosimeters when operating on therapeutic accelerators in planning beam therapy. A monitoring system of the degree of TMS purity by the conductivity and free electron yield is described. A TMS-based microdosimeter can be used in combination with a television-type detector to improve the absorbed dose measurement accuracy in the Bragg peak region.

Tribocorrosion behavior of low friction TiSiCN nanocomposite coatings deposited on titanium alloy for biomedical applications

The quaternary Ti-Si-C-N nanocomposite is regarded to be promising one in the biomedical field due to its improved tribocorrosion performance and biocompatibility. The deposition of such material on biomedical components surfaces can extend its lifespan by minimizing wear debris and ion releasing inside the physiological environment. Therefore, this work investigates the tribocorrosion behavior of low friction Ti-Si-C-N nanocomposite coatings applied on the ASTM F136 titanium alloy immersed in a phosphate-buffered solution (PBS). The coatings were obtained by the plasma-enhanced magnetron sputtering (PEMS) technique using an assorted precursor flow range of tetramethylsilane (TMS) and hexamethyldisilazane (HMDSN) liquid along with acetylene (C2H2) gas. Reciprocal sliding tribocorrosion tests were performed under PBS solution on the samples and compared to a Ti-6Al-4V bare alloy sample. The microstructure, morphology, chemical structure, mechanical properties, and adhesion of the coated samples were also evaluated. The results presented an expressive reduction of at least 97% in the wear rate of the low friction Ti-(Si)-C-N nanocomposite coatings compared to the titanium bare alloy sample. The tribocorrosion performance of the coated samples demonstrated a strong correlation within the Silicon and Carbon content presented on coatings chemical compositions. As consequence, the roles of nanocrystallites refinement, the presence of amorphous carbon region and the oxides generation were demonstrated as relevant characteristics to improve the tribocorrosion behavior of Ti-Si-C-N nanocomposite.

Dose Characteristics of the Ionization Chamber Based on TMS “Warm Liquid”

An ionization chamber is proposed, based on which dose characteristics of organosilicon liquid (tetramethylsilane (TMS)) featuring electronic conductivity at room temperature are studied with the purpose of its application for developing complex radiation detectors and dosimeters for planning beam therapy.