Impurity Peaks Research Articles

Structural and optical analysis of nanostructural CuCrO3 perovskite by sol–gel method

Abstract CuCrO3 perovskite structure synthesized via cost-effective sol–gel method successfully as confirmed by X-ray diffraction (XRD) with smaller crystallite size has been reported. EDS confirmed copper chromite perovskite single phase with no extra impurity peak existence. Agglomerated grains resulting average particle size of 9.6 nm as determined from SEM micrographs. PL spectra shows electron transition from VB to CB whereas Raman spectra shows D and G band presence within spectra pointing towards existence of functional groups within structure. Bandgap value of 4.02 eV is calculated from UV–vis spectra. In order to calculate Eu, which is calculated to be 0.960 Ev. All these properties suggested synthesized material applicability as an optoelectronic perovskite material.

Hydrothermal Synthesis of Special Cubic Form MnO2 and MnCO3 Composite Material for Zinc Ion Battery and its Electrochemical Performance Test

In this paper, the aqueous zinc ion battery cathode material composed of manganese dioxide and manganese carbonate were synthesized by hydrothermal method. By optimizing the temperature and time in both hydrothermal and calcination process, the optimal synthesis conditions were discovered. Then, in order to survey and analysis the characteristics of the material, XRD, SEM, EDS and XPS tests were conducted. It can be seen from XRD test that the main crystal structure is MnO2 and MnCO3, and no other obvious impurity peaks are found. In the SEM test, it can be seen that the main shape of the material is regular cube, and there is triangular pyramidal bulge on the surface of the cube, which can increase the surface area of the material. As can be seen from EDS and element distribution diagram, Mn, O and C elements are evenly distributed. The XPS test shows that the valence states of the synthesized materials are consistent with those of MnO2 and MnCO3. According to the infrared test and Raman test, the characteristic peak vibration of the synthesized material is also consistent with those of MnO2 and MnCO3, indicating that the composite of MnO2 and MnCO3 with high electrochemical stability has been synthesized by hydrothermal method.

The influence of different drying methods on the properties of LiNi0.5Mn1.5O4 material

It was precisely because LiNi[Formula: see text]Mn[Formula: see text]O4 cathode material had many advantages, including high voltage, high power, no pollution, low cost, etc., that it became a research hotspot for lithium-ion cathode materials. Although LiNi[Formula: see text]Mn[Formula: see text]O4 has a three-dimensional Li[Formula: see text] diffusion channel, there are still some problems that lead to capacity decay and reduced cycling stability, limiting its commercial application. In this paper, the LiNi[Formula: see text]Mn[Formula: see text]O4 cathode material was prepared by the freezing precipitation method. We studied the effects of different drying methods, such as blast drying, water bath drying and freeze-drying on the structure, morphology and electrochemical properties of LiNi[Formula: see text]Mn[Formula: see text]O4 cathode materials. The study found that the LiNi[Formula: see text]Mn[Formula: see text]O4 cathode material prepared by the precipitation-freeze-drying method had a complete crystal form, a stable structure and no LixNi[Formula: see text]O impurity peak. The SEM image showed that the particles were smaller and had a smooth surface. The initial discharge-specific capacity at 0.1[Formula: see text]C was 105.2[Formula: see text]mAh⋅g[Formula: see text]. After 50 cycles, its specific discharge capacity was 99.4[Formula: see text]mAh⋅g[Formula: see text] and the capacity retention rate was 94.5%. Compared with LiNi[Formula: see text]Mn[Formula: see text]O4 materials prepared by other methods, it had better electrochemical performance.

Excellent photoluminescence and electrochemical properties of Sm3+ doped Ca2MgSi2O7 nanophosphor: Display and electrochemical sensor applications

A series of orange-red light emitting Ca2MgSi2O7:Sm3+ nanopowders were fabricated via low-cost eco-friendly green combustion technique using Aloe vera gel as fuel. The phase purity of the samples were confirmed by the powder X-ray diffraction (PXRD) technique. Pure single-phase tetragonal structure is observed from the PXRD results with no additional impurity peaks. The band gap energy of the fabricated powders was estimated by diffuse reflectance spectra (DRS) and is found to be in the range of 4.01–5.98 eV. A high resolution scanning electron microscope (SEM) was used to study the morphological behaviour of the samples. Honeycomb-like structures are observed from the SEM results. The particle size was evaluated by transmission electron microscopy (TEM) and is found to be ∼50 nm. The interplanar distance is found to be 0.53 nm. Photoluminescence properties were systematically studied in detail. The phosphors are successfully excited at 403 nm NUV light, producing reddish-orange characteristic emission. The emission peaks are centered at 558 (4G5/2 → 6H5/2), 607 (4G5/2 → 6H7/2) and 645 nm (4G5/2 → 6H9/2), respectively. Among the observed peaks the red emanation (4G5/2 → 6H7/2) is stronger than the orange emission (4G5/2 → 6H5/2) in the current investigation. The photoluminescent concentration quenching is noticed above 5 mol% Sm3+ ion doping content. The dipole–dipole interaction resulting in cross relaxation is found to be the principal cause of concentration quenching mechanism. The color features such as Commission Internationale de l’Eclairage (CIE) and correlated color temperature (CCT) were studied in detail. The optimized chromaticity coordinates were estimated to be (0.6363, 0.3632), which fall in the reddish-orange region. The average CCT value obtained is 3362 K. The average color purity is found to be ∼82%. Sm3+ incorporated Ca2MgSi2O7 samples are possible contender for single white light generation commercial candidates owing to their strong hypersensitivity of Sm3+ ions through host, least possibility for re-absorption of blue-green emission owing to poor direct f–f excitation of Sm3+ ions, and high color purity (reddish-orange emission). The prepared powders exhibit excellent electrochemical redox properties and CPE modified optimized powders show outstanding sensitive response which indicates its use in the potential electrochemical sensor materials for drug sensing studies.

Dissolution of Mg(OH)2 by swift heavy ion irradiation in CoFe2O4/MgO/ZnFe2O4 multilayer thin films

In-situ system for metallic multilayer thin films used for magnetic tunnel junction (MTJ) required a multi-target system to avoid the formation of impurities which make these devices very costly. In this work, the study was performed to resolve this issue by using a single target system for multilayer formation and impurity phases were dissolved by swift heavy ion (SHI) irradiation. A pristine MgO/Si(100) and CoFe2O4/MgO/ZnFe2O4/Si(100) (CFMZF) multilayer thin film were prepared via radio frequency (RF) sputtering technique. These structures were irradiated by 75 MeV oxygen-ion (O-ion) fluence (5x1011, 1x1012, and 5x1012 ions/cm2) and 200 MeV silver-ion (Ag-ion) fluence (1x1012 ions/cm2) for the investigation of structural changes. The high-resolution X-ray diffraction (HRXRD) reveals that MgO and CFMZF thin films have impurity peaks, dissolved via O-ion and Ag-ion irradiation. Further HRXRD analysis confirmed that Ag-ion irradiation dissolves more peaks leaving one small intensity peak of (400) corresponding to MgO. The multilayer stack of CFMZF irradiated via Ag-ion shows that Mg(OH)2 phase were completely dissolved and appears only (311) less intense peak corresponding to the ferrite structure. The findings are also corroborated by cross-sectional field emission scanning electron microscopy of CFMZF multilayer thin film showing damaged layers with Ag-ion irradiation. Therefore, the SHI irradiation technique can be used to dissolve the impurity peaks and improve the interface of the multilayer stacks.

Desired highly efficient Eu3+ activated GdCaAl3O7 orange-red emanating nanophosphors for UV excitable forensic and advanced information encryption and decryption applications

In the present work, orange-red emitting Eu3+ (1–8 mol %) doped GdCaAl3O7 nanophosphors are prepared by a simple solution combustion route. X-ray diffraction studies reveal that the prepared phosphors are in the tetragonal phase without any additional impurity peaks. Morphological studies clearly show the irregularly shaped network-type structures of the phosphors. Under UV light excitation (∼393 nm), photoluminescence (PL) emission peaks are recorded at ∼578, 590, 617, 651, and 701 nm, which correspond to the 5D0→7F0, 1, 2, 3, 4 transitions of Eu3+ ions, respectively. The photometric properties of the prepared nanophosphors reveal color tuning from the orange-red region to the pure red region with a color purity of ∼88.14 %. The optimized GdCaAl3O7:Eu3+ (3 mol %) nanophosphor is evaluated from an application perspective by developing latent fingerprints and lip prints. The visualized latent fingerprints under ∼254 and 375 nm excitations undoubtedly reveal levels I–III ridge features on various surfaces. The developed lip prints can discriminate the Suzuki's and Tsuchihashi’s categories. The information encryption and decryption capabilities of the nanophosphor on various surfaces were investigated by following screen printing technology, dip-pen and brush mode. The printed patterns revealed sharp, high resolution, uniform ink distribution under ∼254 nm UV excitation and invisible upon normal light. The overall results revealed that prepared GdCaAl3O7:Eu3+ (1–8 mol %) NPs exhibit excellent structural stability and intensive PL emission endorsing its applicability wide scope of areas.

Effect of precursor particle size of NiO-YSZ electrodes in its physico-chemical and electrical conductivity properties for solid oxide electrochemical cells

Electrodes play an important role in the overall performance of solid oxide electrochemical cells (SOC), such as for fuel cell or electrolysis cell applications. Desirable properties of the electrode include good morphological features with high electronic and ionic conductivity. In this study, in order to investigate the effect of precursor particle size on the microstructure and conductivity properties of nickel oxide and yttria-stabilized zirconia (NiO-YSZ), precursors were prepared with different particle sizes using a planetary ball mill via varying the milling speed and milling time. From the particle size analysis (PSA) of the milled samples based on the studied milling parameters, it was observed that the milling time had a significant effect on the resulting ball-milled samples compared to the effect of the milling speed. However, upon sintering to obtain the NiO-YSZ electrode composites, the effect of milling speed, in terms of grain size, can be observed. From the XRD patterns, major peaks can be attributed to cubic phases of NiO and YSZ; however, traces of ZrO2 impurity peaks can be seen for the precursor sample with higher milling speed. SEM-EDX analyses support the more agglomerated morphology for the sample with longer milling duration and larger grains for those with higher milling speed. The obtained total bulk conductivities for the sample milled at 400 rpm (10 h) is about 1.27x10-1 S/cm, and for the 400 rpm (20 h) is about 1.77x10-1 S/cm with Ea of 0.88 eV and 0.27 eV, respectively.

Synthesis and characterization of dielectric, electric, and magnetic properties of vanadium doped-bismuth europium ferrites for multiferroic applications

Polycrystalline Bi0.90Eu0.10Fe1-xVxO3 (BEFVO) (where x = 0.00 to 0.10) ceramics were synthesized by the solid-state reaction method. The X-ray diffraction (XRD) pattern revealed that all the samples possess hexagonal crystal structures with some impurity peaks. Gold Schmidt’s tolerance factor of the samples was found 0.8436 to 0.8478 which represents more stability of the doped BiFeO3 (BFO) than parent BFO. The crystallite size was found in the range of 65–33 nm. The density gradually increases with increasing the V concentration and the maximum bulk density (ρB = 6.981 g/cm3) is obtained for the x = 0.10 sample. The obtained average grain size is found in the micrometer range and the values are in the range of 1.31–0.74 µm. The maximum dielectric constant of 2577 at 102 Hz is found for the x = 0.07 sample. The resistivity decreases with doping concentration as a result of ac conductivity increases. The highest transition frequency of long-range to short-range mobility of charge carriers is obtained for the x = 0.07 sample. The highest real part of the initial permeability of 25.24 is found for x = 0.07 multiferroic ceramics. For the x = 0.07 sample, the maximal saturation magnetization is found to be 1.91 emu/g. The studied samples comprise large electric polarization and the optimum polarization of 7.5 μc/cm2 is observed for the x = 0.07 composition.

Structural and optical properties of polyvinyl alcohol/copper oxide (PVA/CuO) nanocomposites

In the present investigation, pristine polyvinyl alcohol (PVA) and copper oxide (CuO) incorporated nanocomposite films have been fabricated via simple solution cast technique. The structural and optical properties of the prepared films were studied in detail. Various concentrations of CuO NPs (0.1–0.4 wt %) incorporated in the PVA film were prepared. The X-ray diffraction (XRD) profiles indicate the presence of CuO nanoparticles (NPs) in PVA film. XRD results indicate that, the CuO NPs were successfully incorporated into the PVA host matrix with no additional impurity peaks. The obtained CuO NPs belong to the monoclinic phase as confirmed by the XRD results. The peak observed at 2θ = 19.4° evident for the formation of semi crystalline PVA polymer. The average crystallite size of the prepared NPs was observed to be ∼0.52 nm. The vibrational bands present in the prepared films were confirmed by the Fourier transform infra-red spectroscopy (FTIR) plots. The presence of the NPs in the films was further investigated with the help of Raman spectra. UV–visible optical absorption spectra was recorded to evaluate the band gap values of the prepared films. The band gap value for pristine PVA was found to be 5.35 eV and it decreases with increase of CuO NPs concnetration owing to the change in the electronic structure of the pure PVA. The dielectric properties were also evaluated and it was found that, with increase in the CuO NPs concentration the dielectric constant also increases owing to the increase in density of states leading to the formation of polarization. The optical conductivity of the prepared nanocomposites increases with increase in the NPs concentration due to the formation of the charge transfer complex. The obtained results reveal that, the addition of CuO NPs reduces the optical band gap of the PVA polymer films.

Near infrared fluorescence properties of Tb4+ and Tb3+ inter-conversion states in CaF2:Yb3+nanocrystals

Near infra-red emission was enhanced in calcium fluoride (CaF2) co-doped with terbium ions and ytterbium (Yb3+) under a 325 nm laser excitation wavelength, during investigations performed for possible application in Si solar cells. Tb3+ ions were oxidized to Tb4+ ions and emission enhancement occurred due to a cooperative energy transfer mechanism between the Tb4+-Yb3+ couple. The oxidation of Tb3+ ions in CaF2 was achieved by annealing the nanocrystals at 450 °C in air. X-ray diffraction analysis confirmed the cubic face of the CaF2 crystal without any impurity peaks. UV–VIS luminescence and X-ray photoelectron spectroscopy were conducted to probe the conversion of Tb3+ to Tb4+ ions as a function of the annealing time. The main conclusion was that the NIR emission from the Tb4+-Yb3+ couple revealed that down-conversion occurred through a cooperative energy transfer mechanism.

Structural and Photoluminescence Properties of Pr, Cu Co-Doped ZnO Nanoparticles Synthesized by Chemical Co-Precipitation Method

At room temperature, zinc oxide (ZnO) nanoparticles co-doped with praseodymium (Pr) and copper (Cu) using a low-cost chemical co-precipitation method. As a capping agent, polyvinylpyrrolidone (PVP) was used for synthesizing the nanosamples, and a pH of 9 was maintained. The synthesis of nanosamples was then characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and photoluminescence (PL). X-ray diffraction studies revealed the wurtzite hexagonal structure of ZnO, and no impurity peaks were found. The particle size obtained from XRD studies was 32 to 46 nm and is well supported by TEM. SEM micrographs demonstrated the surface morphology of the samples. With Cu dopant concentration, Pr-doped ZnO nanosamples exhibited enhanced luminescence properties.

Structural and magnetic conduct in Sm and Al substituted Ba0.9Sm0.1Fe10Al2O19 M-type hexaferrites at different sintering temperatures

The hexagonal ferrites with composition Ba0.9Sm0.1Fe10Al2O19 has been prepared by using conventional solid state reaction method. As prepared samples were then sintered at different sintering temperatures to analyze the effects on magnetic and structural properties of Barium hexa ferrites. These samples were then characterized by using various techniques. For structural characterization x-ray diffraction technique was used. XRD results confirmed phase pure hexagonal structure. No impurity peaks were observed. For Morphological analysis of all the samples Scanning Electron Microscopy (SEM) was utilized. SEM micrographs suggested the formation of hexaferrites material with homogenous distribution of particles. Magnetic properties were measured by permanent magnetic measuring system. Magnetic conduction of material was tested under varying magnetic field of ± 30 KOe at room temperature. The saturation magnetization value was observed 48.55 emu g−1 and coercivity 5.01KOe for the sample sintered at 1220 °C. As the sintering temperature rises, the values for magnetic saturation decreases to 46.24 emu g−1 and coercivity increases up to 5.26 KOe at 1270 °C.

Investigation of the effect of sintering temperatures on the structural and magnetic properties of (Bi0.90Sm0.10Fe0.93Cr 0.07O3) ferrite

Rare earth samarium (Sm) and transition metal chromium (Cr) doped bismuth ferrites (Bi0.90Sm0.10Fe0.93Cr 0.07O3) are successfully fabricated using a solid state reaction method at various sintering temperatures (Ts). The distorted rhombohedral structure was confirmed by X-ray diffraction with R3c space group for 800 and 850 °C sintered compositions with some impurity peaks. The distorted rhombohedral phase changes slightly in the pseudo-cubic phase at 900 °C Ts with a nominal reduction in the percentage of some secondary phases. The average crystallite size of compositions is decreased from 71 to 23 nm and lattice strain is increased from 0.108 to 0.313% with increasing Ts. The value of the Gold-Schmidt tolerance factor is 0.84 which indicates the stabilized form of the ferrites. Field Emission Scanning Electron Microscopy images reveal the surface morphology of the compositions, and it is found that the grain size increases from 0.868 to 1.29 μm with increasing Ts. Increasing trends and a long range of frequency stable permeability suggest these compositions to use in high frequency devices. In magnetic hysteresis loops, the exchange bias effect in the negative axis direction is observed that is gradually increased with Ts. Saturation magnetization is increased from 1.780 to 1.975 emu/g following the increment trend of Bhor magnetic moment from 0.256 to 0.320 μB. The squareness ratio suggests the formation of a multidomain structure in the polycrystalline ferrites.

Efficient red-emitting SrZrO3:Eu3+ phosphor superstructures for display device applications

In the present report, a series of intense red light emitting SrZrO3:Eu3+ nanopowders were fabricated via low-cost eco-friendly hydrothermal route using Aloe vera gel as surfactant. Upon utilizing the powder X-ray diffraction (PXRD) method the phase of the prepared nanopowders were evaluated. Pure single-phase tetragonal structure was observed from the PXRD results with no additional impurity peaks. The energy band gap of the fabricated powders was calculated by diffuse reflectance spectra (DRS) and found to be around 3.98 – 4.27 eV. High resolution scanning electron microscope (SEM) was utilized to study the morphological behavior of the prepared powders. Honeycomb-like structures were observed from the SEM micrographs. The particle size was evaluated by transmission electron microscopy (TEM) and observed to be ∼ 42 nm. The interplanar distance was found to be around 0.32 nm. Photoluminescence properties were systematically studied in detail. The phosphors were successfully excited at 395 nm NUV light, producing intense red characteristics emission. The emission peaks were centered at 585 nm (5D0→7F1), 613 nm (5D0→7F2) and 648 nm (5D0→7F3). The photoluminescent concentration quenching was noticed beyond 5 mol% Eu3+ ion doping content. The dipole-dipole interaction resulting in cross relaxation was found to be the principal cause of concentration quenching mechanism. The color features such as Commission International de I'Eclairage (CIE) and correlated color temperature (CCT) were studied in detail. The optimized chromaticity coordinates were estimated to be (0.67, 0.32), which falls in the intense red region. The average CCT value obtained was 4328 K. The color purity was observed around ∼ 88%. In addition, the average internal quantum efficiency was calculated, and it was found to be 48%. The prepared powders exhibit excellent luminescence properties, quantum efficiency and high color purity. The obtained results indicate the possibility of the present powders in the fabrication of the red-light emitting diode applications.

Synergetic effects of Mo2C sphere/SCN nanocatalysts interface for nanomolar detection of uric acid and folic acid in presence of interferences

Till to date, the application of sulfur-doped graphitic carbon nitride supported transition metal carbide interface for electrochemical sensor fabrication was less explored. In this work, we designed a simple synthesis of molybdenum carbide sphere embedded sulfur doped graphitic carbon nitride (Mo2C/SCN) catalyst for the nanomolar electrochemical sensor application. The synthesized Mo2C/SCN nanocatalyst was systematically characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM) with elemental mapping. The SEM images show that the porous SCN network adhered uniformly on Mo2C, causing a loss of crystallinity in the diffractogram. The corresponding elemental mapping of Mo2C/SCN shows distinct peaks for carbon (41.47%), nitrogen (32.54%), sulfur (1.37%), and molybdenum (24.62%) with no additional impurity peaks, reflecting the successful synthesis. Later, the glassy carbon electrode (GCE) was modified by Mo2C/SCN nanocatalyst for simultaneous sensing of uric acid (UA) and folic acid (FA). The fabricated Mo2C/SCN/GCE is capable of simultaneous and interference free electrochemical detection of UA and FA in a binary mixture. The limit of detection (LOD) calculated at Mo2C/SCN/GCE for UA and FA was 21.5 nM (0.09 – 47.0 μM) and 14.7 nM (0.09 – 167.25 μM) respectively by differential pulse voltammetric (DPV) technique. The presence of interferons has no significant effect on the sensor’s performance, making it suitable for real sample analysis. The present method can be extended to fabricate an electrochemical sensor for various molecules.

The facile synthesis of 3D hierarchical flower-like TiO2 microspheres with enhanced photocatalytic activity

A 3D hierarchical flower-like rutile TiO2 microspheres assembled by well-aligned 1D nanorods were efficiently synthesized using the solvothermal method at a temperature of 140 °C for 5 h. The synthesized TiO2 microspheres have an average crystallite size of about 6.9–8.4 nm. According to SEM, FESEM and TEM analysis, flower-like TiO2 microspheres are made up of nanorods that grow radially from the center and are several nm thick on average. The XRD, EDS and XPS analysis revealed that titanium and oxygen peaks were present with no other impurity peaks. The volume ratio of water and toluene plays a vital role that was significantly affecting the chemical properties of synthesized TiO2 materials. Compared to other samples, the hierarchical 3D TiO2 microspheres Ti(1:1) had a small crystallite size, a lower bandgap, a comparatively large BET surface area of about 130 m2/g and a pore volume of 0.179 cm3/g, which revealed more favorable for photocatalytic activity. Ti(1:1) photocatalyst degraded MO by almost 96 and 94% within 50 and 40 min, respectively, when exposed to mercury light and sunlight. Also, it showed that within 60 min of mercury light irradiation, RhB degraded up to 65%. Additionally, an LC-MS study was performed for the degradation of MO dye solution and a possible degradation path was proposed.

Graphene quantum dots (GQDs) decorated Co-Zn ferrite: Structural, morphological, dielectric, and magnetic properties

GQDs/Co0.5Zn0.5Fe2O4 nanocomposite was synthesized using a facile sonication-assisted approach. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), elemental dispersive X-ray spectroscopy (EDX), impedance analyzer and vibrating sample magnetometer (VSM) were employed to characterize the synthesized samples. The XRD data confirmed the formation of GQDs, Co-Zn ferrite and GQDs/Co-Zn ferrite nanocomposite with no detectable impurity peaks. FTIR results identified the presence of GQDs in GQDs/Co-Zn ferrite nanocomposite. The morphological study revealed the decoration of spherical GQDs on the surface of Co-Zn ferrite. Complex impedance plane plots showed the contribution of the relaxation phenomenon associated with grain and grain boundaries in observed dielectric properties of the nanocomposite. The inclusion of GQDs led to the enhancement of the dielectric constant of the nanocomposite at low frequencies. GQDs/Co0.5Zn0.5Fe2O4 showed superparamagnetic properties which makes it a potential material to be used as a contrast agent in magnetic resonance imaging (MRI) applications.

Growth of 2-inch diamond films on 4H–SiC substrate by microwave plasma CVD for enhanced thermal performance

We report a novel method of producing composite substrates by growing diamond films on a 4H–SiC substrate by microwave plasma chemical vapor deposition to enhance the thermal management for thermal diffusion applications in GaN-based RF power devices. Morphology, grain orientation and structure of the diamond films were characterized by scanning electron microscopy, electron backscatter diffraction, X-ray diffraction and Raman spectroscopy. The diamond films were uniform and compact, without voids and gaps observed via cross-sectional view of microscopy, and without any graphite phase and impurity peak. Thermal conductivity (TC) of the diamond-SiC composite substrates was simulated and calculated. Results indicate that the TC of the composite substrates is up to 512.02 ± 6.37 W m−1 K−1 when the SiC thickness is 500 μm, which is 1.53 ± 0.02 times of the pure SiC substrate, and this high TC increases to 1171.13 ± 67.23 W m−1 K−1 after the 4H–SiC substrate is thinned down to 50 μm. The coefficient of thermal expansion (CTE) of the composite substrates can be engineered by changing the thickness of SiC substrate.

Cytotoxic and osteogenic property of trilaurin assisted hydroxyapatite nanorods in simulated body fluid environment

In this research work, the cytogenic and osteogenic properties of biomimetically synthesised nanohydroxyapatite (nanoHAP) powders using Trilaurin (TL), as a surfactant was attempted. Microwave (MW) and ultrasound (US) technologies were also employed to enhance the efficacy of the method. Different HAP samples were prepared using 1.5 times concentrated Simulated Body Fluid (SBF) with 1, 5 and 15 days immersion inorder to achieve pure nanohydroxyapatite powders. The formation of HAP was well supported by FTIR and Raman spectroscopy, which shows no impurity peaks. By increasing the time of soaking in SBF, growth, size and crystallinity of HAP were found to decrease as evidenced by XRD data. HRSEM studies reveal that nano-plates and rod shaped nano HAP could be obtained by this method. So the obtained TL assisted HAP exhibits high thermal stability as confirmed by TGA analysis. The invitro cytotoxicity was evaluated by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-tetrazolium bromide (MTT) assay using human osteoblastic cell line (MG-63) and Michigan Cancer Foundation-7 (MCF-7) breast cancer cell line. The obtained result supports the osteoblast property and less toxicity. Inorder to further prove the osteoblast property, trypan blue exclusion test (live dead assay) were carried out using MG-63 cell line and the obtained results favours the bone forming ability.

ИДЕНТИФИКАЦИЯ ПРИМЕСЕЙ В ФАРМАЦЕВТИЧЕСКОЙ СУБСТАНЦИИ ЛХС-1269 МЕТОДОМ ВЭЖХ-МСМС

The N.N. Blokhin Oncology Research Center synthesized indolo[2,3-a]carbazole N-glycoside, which received the laboratory cipher LСS-1269, which showed a pronounced antitumor effect during research.. During the study of LСS-1269 by HPLC, the presence of two impurities was revealed, called LСS-1269-X and LСS-1269-Y (impurities X and Y). The electronic absorption spectrum (EAS) of the impurity peak X was similar to the EAS of the indolo[2,3-a]carbazole N-glycoside obtained and described earlier under the laboratory cipher LCS-1208, and the EAS of the impurity was the spectrum of LCS–1269, which indicates that the impurities belong to indolo[2,3-a]carbazoles. In this regard, it is suggested about the structure of these impurities: impurity X is a xyloside of aglycone similar in structure to aglycone LCS-1208, which can be formed as a by-product at one of the last stages of the synthesis of LCS-1269, and impurity Y has the structure of triacetyl ester LCS-1269, which is a precursor of LCS-1269 in the synthesis process. The aim of the work was to identify impurities in the substance LHS-1C69, to confirm their structures and belonging to derivatives of indolo[2,3-a]carbazole. The identification of impurities in the substance LCS-1269 was carried out using the HPLC-MSMS method. For this purpose, X and Y impurities having the assumed structures were obtained by directed counter synthesis, which were used as reference samples. Comparison of peak retention times on extracted ion chromatograms (XIC) and MSMS spectra of impurities with XIC and MSMS spectra of samples of comparison of the alleged impurities confirmed their structure. As a result of the work carried out, the structures of impurities X and Y were identified and the affiliation of these impurities to derivatives of indolo[2,3-a]carbazole was confirmed.