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In recent years, demand for scintillation detectors with high time resolution (better than 100 ps) has emerged in high-energy physics and medical imaging applications. In particular, time of flight positron emission tomography (TOF-PET) can greatly benefit from increasing time resolution of scintillators, which leads to the increase of signal-to-noise ratio, decrease of patient dose, and achievement of the superior spatial resolution of PET images. Currently, extensive research of various types of materials is carried out to achieve the best time resolution. In this review, the recent progress of various approaches is summarized and scintillation compounds with the best temporal characteristics are first reviewed. The review presents the physical processes causing fast luminescence in inorganic and organic materials. Special attention is paid to nanocomposites which belong to a new perspective class of scintillating materials, consisting of a plastic matrix, inorganic nanocrystalline fillers, and organic or inorganic luminescence activators and shifters. The main features and functions of all parts of existing and prospective nanocomposite scintillators are also discussed. A number of currently created and investigated nanocomposite materials with various compounds and structures are reviewed.

The microstructure of polymer-derived ceramics (PDCs) was closely related to processing. This study demonstrated that SiCN matrix prepared by polymer infiltration and pyrolysis (PIP) at 900 °C inside a Si3N4 whisker (Si3N4w) preform with submicro-sized pores differed from its powder-consolidated analogue in both the content and structure of free carbon. Chemical analysis showed that PIP process had a higher free carbon yield. Raman spectroscopy and transmission electron microscopy (TEM) observation discovered a higher graphitization degree of free carbon and the existence of nanocrystalline graphite in SiCN matrix. Dielectric properties of Si3N4w/SiCN composites were greatly enhanced when volume fraction of SiCN matrix reached 24.5% due to dielectric percolation caused by highly-lossy free carbon. Reconsolidation of hydrocarbon released during pyrolysis by gas-state carbonization in Si3N4 whisker preform was supposed to account for the high yield and graphitization degree of free carbon in PIP process.

In this work, the nitriding efficiency in an ultrafine-grained iron was investigated. Prior to nitriding, the ultrasonic nanocrystalline surface modification (UNSM) technique was used to process the coarse-grained iron to obtain ultrafine-grained iron. Gas nitriding was conducted for the UNSM-treated iron and the coarse-grained iron at temperatures from 300 °C to 560 °C. The results indicate that the combination of UNSM and nitriding provide much higher efficiency for hardening than the sum of the efficiencies of UNSM alone and nitriding alone. Nitride nucleation was confirmed in the diffusion layer of the UNSM-treated iron following the nitriding process, enhancing the hardness after nitriding. X-ray diffraction patterns were obtained for both the UNSM-treated iron subjected to nitriding as well as iron that underwent only nitriding at different temperatures. It was also found that the minimum temperatures required to form nitrides, including γ′-Fe4N, e-Fe3N, e-Fe2N, and FeN, were reduced because of the high chemical potential at the grain boundaries. The theoretical analysis suggests that heterogeneous nitride nucleation at grain boundaries is the key factor that contributes to the enhancement in hardness in the nitriding layer in ultrafine-grained metals and nanocrystalline metals.

Refractory high-entropy alloys (HEAs) possess many useful properties such as high strength and high-temperature stability. So far, most studies on refractory HEAs have been limited to a few well-known compositions and on their coarse-grain bulk forms. Here we fabricate nanocrystalline (TiZrHf)x(NbTa)1−x HEA thin films with a large range of compositions (x = 0.07–0.90) by the direct current (DC) magnetron co-sputtering technique and measure their mechanical properties using the nanoindentation method. All the as-deposited HEA thin films show a solid-solution body-centered cubic (bcc) structure. As the compositional ratio (x) increases, the elastic modulus decreases from 153 to 123 GPa, following the trend of the rule of mixture. As x increases, the hardness first decreases from 6.5 GPa (x = 0.07) to the lowest value (4.6 GPa, x = 0.48) and then increases to the highest value (7.1 GPa, x = 0.90), showing a concave trend. The change in hardness might be attributed to the combinational influence caused by the atomic size and modulus effects, as well as the texture effect. The authors also propose a few open questions for future studies on this and related HEA systems.

The technique of mechanical alloying, although originally developed to produce oxide-dispersion-strengthened superalloys for aerospace and high-temperature applications, is now recognized as an important and versatile technique to synthesize metastable and advanced materials with a high potential for widespread applications. Mechanical alloying involves repeated cold welding, fracturing, and rewelding of powder particles in a high-energy ball mill. The reduced diffusion distances between metal powder layers formed as a result of heavy deformation, introduction of a high density of crystal defects, and a slight rise in powder temperature contribute to alloy formation from blended elemental powders. The type of phases/materials produced by mechanical alloying of powder mixtures include supersaturated solid solutions, intermetallics, quasicrystalline alloys, high-entropy alloys, amorphous alloys, and composites. If the material produced is crystalline in nature, most often the grain size is in the nanometer size. Amongst these phases, nanostructured materials and nanocomposites have been the most important types investigated. In this contribution, we will present an overview of the processing, characteristics, and properties of nanocrystalline materials and nanocomposites produced by mechanical alloying, with special emphasis on our recent work.

Nanocrystalline metal ferrites (MFe2O4, M = Co, Ni, Cu, Mg, and Zn) were successfully synthesized via autocombustion synthesis using egg white. X-ray diffraction (XRD) measurements revealed the crystallization of the entire ferrites either in the tetragonal structure, such as in the case of CuFe2O4, or cubic spinels such as in other studied ferrites. The Fourier transform infrared spectral study revealed the characteristic vibration bands of ferrites. Compared to other synthesis methods, the observed variation in the obtained structural parameters could be due to the different cation distribution of the prepared ferrites. In agreement with XRD measurements, the transmission electron microscopy images showed agglomerated particles with cubic morphology for all ferrites. On the other hand, CuFe2O4 showed tetragonal morphology. The magnetization values were found to vary with the type of the metal ion, and CoFe2O4 showed the highest one (42.8 emu/g). Generally, the lower magnetization values obtained than those reported in the literature for all studied ferrites could be attributed to the smaller particle sizes or the cation redistribution. The obtained coercivity values are observed to be higher than their related values in the literature, exhibiting the impact of the present synthesis route. Ac-conductivity as a function of temperature and frequency indicated semiconducting properties with the observed change in the conduction mechanism by increasing the temperature. The obtained low dielectric constant values could suggest using the entire ferrites in high-frequency applications such as microwave devices.

Understanding surface reconstruction of nanocrystals is of great importance to their applications, however it is still challenging due to lack of atomic-level structural information under reconstruction conditions. Herein, through in situ spherical aberration corrected scanning transmission electron microscopy (STEM), the reconstruction of nanocrystalline SnO2 (110) surface was studied. By identifying the precise arrangements of surface/subsurface Sn and O columns through both in situ bright-field and high-angle annular dark-field STEM images, an unexpected added Sn2O model was determined for SnO2 (110)-(1 × 2) surface. The protruded Snδ+ of this surface could act as the active sites for activating O2 molecules according to our density functional theory (DFT) calculations. On the basis of in situ observation of atomic-level reconstruction behaviors and DFT calculations, an energy-driven reconstruction process was also revealed. We anticipate this work would help to clarify the long-standing debate regarding the reconstruction of SnO2 (110) surface and its intrinsic property.

The Zn1-xBixO (0 ≤ x ≤ 0.1) combustion products were synthesized by solution combustion method using Zn(NO3)2·6H2O and Bi(NO3)3·5H2O as oxidizers and glycine as a fuel. To enhance the solubility of Bi in the ZnO hexagonal structure, the different portions of the combustion products were subsequently annealed (600 °C/5 h) and ball-milled under 350 rpm for 10 h. The various multifunctional Zn1-xBixO materials were analyzed by different characterization techniques (XRD, TG–DTA, FT-IR, NIR, Raman, and FESEM-EDX) to explore the physico-chemical properties. In a wide range of composition (x), only the x = 0 and 0.02 revealed a single hexagonal phase with a Zn1-xBixO structure for the combustion products and annealed samples. Remarkably, the multifunctional nanocrystalline Zn1-xBixO (0 ≤ x ≤ 0.1) materials were successfully obtained in phase pure form upon subsequent ball-milling of the combustion products, while the annealing treatment failed to enhance the solubility of Bi for x = 0.04, 0.06, 0.08, and 0.1. As the combustion products and annealed materials show higher NIR reflectance in the NIR region for x = 0, 0.02, maybe used as solar protecting color pigment materials. Though the ball milling of combustion products enhanced the solubility of Bi in the ZnO structure, it heavily affected the NIR reflectance of Zn1-xBixO. Agglomeration of fine particles is observed in the FESEM micro-images of Zn1-xBixO; x = 0.1 (ball-milled) materials. From the present research findings, we conclude that high-energy ball milling has a substantial impact on the phase formation and the properties of the ball-milled Zn1-xBixO samples.

New directions of development of the scientific school of Yakov Aleksandrovich Ugai “Solid state chemistry and semiconductors” were considered for the direction “Study of semiconductors and nanostructured functional films based on them”, supervised by I. Ya. Mittova. The study of students and followers of the scientific school of Ya. A. Ugai cover materials science topics in the field of solid-state chemistry and inorganic and physical chemistry. At the present stage of research, the emphasis is being placed precisely on nanoscale objects, since in these objects the main mechanisms of modern solid-state chemistry are most clearly revealed: the methods of synthesis - composition - structure (degree of dispersion) - properties. Under the guidance of Professor I. Ya. Mittova DSc (Chem.), research in two key areas is conducted:“Nanoscale semiconductor and dielectric films” and “Doped and undoped nanocrystalline ferrites”. In the first area, the problem of creating high-quality semiconductor and dielectric nanoscale films on AIIIBV by the effect reasonably selected chemostimulators on the process of thermal oxidation of semiconductors and/or directed modification of the composition and properties of the films. They present the specific results achieved to date, reflecting the positive effect of chemostimulators and modifiers on the rate of formation of dielectric and semiconductor films of the nanoscale thickness range and their functional characteristics, which are promising for practical applications.Nanomaterials based on yttrium and lanthanum orthoferrites with a perovskite structure have unique magnetic, optical, and catalytic properties. The use of various approaches to their synthesis and doping allowing to control the structure and properties in a wide range. In the field of magnetic nanocrystals under the supervision of Prof. I. Ya. Mittova studies of the effect of a doping impurity on the composition, structure, and properties of nanoparticles of yttrium and lanthanum orthoferrites by replacing the Y(La)3+ and Fe3+ cations are carried out. In the Socialist Republic of Vietnam one of the talented students of Prof. I. Ya. Mittova, Nguyen Anh Tien, performs studies in this area. To date, new methods for the synthesis ofnanocrystals of doped and undoped ferrites, including ferrites of neodymium, praseodymium, holmium, etc. have been developed.

The ability to control the mechanical properties of metal alloys is an urgent task in materials science. For formation of certain operational properties, in most cases, it is enough to treat the working surface of the product by laser radiation. Classical processing methods are ineffective in relation to multicomponent amorphous-nanocrystalline metallic alloys. This is due to their limited use. Usually, this treatment leads to the loss of unique properties the amorphous-nanocrystalline material. Increasing crack resistance and microhardness is not an easy problem. The structure of an amorphous nanocrystalline material can be destroyed under the action of laser processing. Laser nanosecond treatment, as result of a complex effect on the surface, slightly affects the structure of material. The treated material is characterized by increased microhardness and crack resistance, while at the same time such changes may be controlled.

One of the most important purposes of materials science is the ability to govern the physical properties of materials characterized by different structures. The strength properties of nanostructured metal alloys do not always meet the exploitation requirements. The set of properties of such materials is stable within narrow limits: temperature, mechanical, and corrosion conditions. Traditional processing modes are ineffective for such materials. Attempts to use them often lead to the loss of unique physical and chemical properties. The most effective methods of processing such materials are associated with the use of laser radiation. The laser pulse has a number of features, including a complex effect on the surface layers of the material. Spot and short irradiation with high-energy rays can preserve the unique physical properties of samples as a whole and improve strength indicators without destroying the structure of the material as a whole.

In this work, the very rapid one-step mechanochemical synthesis of nanocrystalline ternary chalcogenide chalcostibite CuSbS2 prepared from copper, antimony, and sulfur precursors by high-energy milling for only 30 min in a planetary mill is reported. XRD confirmed the orthorhombic crystal structure of CuSbS2. The crystallite size of CuSbS2 calculated by LeBail refinement of the X-ray powder diffraction data was 25 nm. The nanocrystalline chalcostibite CuSbS2 was also confirmed by transmission electron microscopy. The purity of CuSbS2 was verified by Raman spectroscopy. The synthesized chalcostibite exhibits the specific surface area value of 2.4 m2g−1. UV–Vis spectroscopy showed the optical bandgap of CuSbS2 as 1.54 eV with wide range of absorption in visible region. Photoresponse of CuSbS2 was confirmed by I–V measurements under dark and light illumination. The proposed mechanochemical synthesis provides an alternative approach to prepare also other ternary semiconductor nanomaterials. CuSbS2 semiconductor nanocrystals have the potential to be used as light absorbers in photovoltaics.

PVA used in packaging applications has been faced with a UV light degradation challenge, which often reduces its durability while in use. The UV light stability enhancement effect of nanocrystalline cellulose (NCC) reinforcement in PVA was studied. Polyvinyl alcohol composite film was reinforced with NCC from palm oil waste (PVA-NCC film) and exposed to UV light (22 W, SUV-16 254 nm) for different time duration to study the material durability enhancement. The percentage weight loss of the samples was measured to observe the UV light degradation effect. Furthermore, the samples’ structural, morphological, and tensile properties were studied before and after exposure to UV light with FT-IR, scanning electron microscopy (SEM), and tensile test. The results showed physical degradation, morphological and tensile properties enhancement of PVA with NCC’s addition. The addition of NCC to the PVA matrix reduced the degradation rate under UV light significantly. Also, the percentage of weight loss was observed to change with the exposure time to UV light.

A micromechanics-based model is developed to capture the grain-size dependent superelasticity of nanocrystalline shape memory alloys (SMAs). Grain-size effects are incorporated in the proposed model through definition of dissipative length scale and energetic length scale parameters. In this paper, nanocrystalline SMAs are considered as two-phase composites consisting of the grain-core phase and the grain-boundary phase. Based on the Gibbs free energy including the spatial gradient of the martensite volume fraction, a new transformation function determining the evolution law for transformation strain is derived. Using micromechanical averaging techniques, the grain-size-dependent superelastic behavior of nanocrystalline SMAs can be described. The internal length scales are calibrated using experimental results from published literature. In addition, model validation is performed by comparing the model predictions with the corresponding experimental data on nanostructured NiTi polycrystalline SMA. Finally, effects of the internal length scales on the critical stresses for forward and reverse transformations, the hysteresis loop area (transformation dissipation energy), and the strain hardening are investigated.

This work examine the potential of ZrB2 in the presence of Ni-P-Zn sulphate rich bath coating on mild steel under change in time from 10-25 min. The coating pH of 5, current density of 1 A/cm2, and stirring rate of 250 rpm was considered in the fabrication process. The microstructure evolution and properties of the deposited coating was analysed using a scanning electron microscope enhanced with energy dispersive spectroscopy (SEM/EDS). All deposited composite coating was investigated in 0.5 M H2SO4 and 3.5% NaCl with the help of linear polarization and open circuit potential. From the result, a solid crystal formation containing zirconium boride was seen from the SEM study. At 25 min a remarkable dispersed and even thin film was noticeable at the interface. From all indication, coating produced with Ni-P-Zn-10ZrB2 at 25 min provides a passive response against corrosion damage. Keywords: Electrodeposition, interface, nanocrystalline, structure, coating

The distribution of dopant atoms plays a key role in the effectiveness of doping, thereby requiring delicate characterizations. In this study, we found that energy-dispersive X-ray spectroscopy (EDX) and electron energy loss spectroscopy (EELS) techniques in scanning transmission electron microscopy (STEM) were not adequate to reveal the distribution of yttrium and the chemical composition of the ZrO2/SiO2 heterophase interface in an yttrium-doped ZrO2-SiO2 nanocrystalline glass-ceramic. Atom probe tomography (APT) is rarely utilized to characterize ceramics due to some inherent difficulties. However, we successfully revealed the three-dimensional distribution of ZrO2 nanocrystallites and SiO2 matrix at the atomic scale with APT under optimized and well-controlled conditions. We also found that the ZrO2 nanocrystallites had a special core-shell structure, with a thin Zr/Si interfacial layer as a shell and a ZrO2 solid solution as a core. Yttrium dopants showed interfacial segregation at both ZrO2 grain boundaries and the ZrO2/SiO2 heterophase interfaces.

The phases, microstructures, and their formation mechanisms of cast zirconium-containing 304 stainless steel (304SS-Zr) alloys with excellent mechanical properties were investigated. Optical microscopy, scanning electron microscopy, transmission electron microscopy, and statistical analysis were employed to further understand the structure–property relationships. The in situ three-phase composite microstructure in 304SS-Zr alloys consisting of micron-sized (MS) austenite, MS intermetallic, and nanocrystalline (NC) ferrite was obtained by simple vacuum melting route. As zirconium (Zr) content increased, the grain sizes of austenite and ferrite became significantly refined. The multiple heterogeneous structures in 304SS-Zr alloys produced the super-high strength which also had higher strain hardening than conventional 304SS. For expanding the nanostructure design ideas, in this work, all the phases were identified and the mechanisms related to phases and microstructure evolution were analyzed from both the kinetic and thermodynamic aspects. For the development of high-performance 304SS-Zr alloys, the mechanical behaviors and strain-hardening mechanisms were also discussed.

A acrilonitrila (ACN) é amplamente usada na produção de borrachas e resinas, mas também considerado um poluente perigoso nos gases de exaustão industrial. Esse trabalho tem como objetivo avaliar a atividade e seletividade de catalisadores comerciais de óxidos de cobre (CuO), níquel (NiO) e cério (CeO2), na reação de combustão catalítica seletiva de acrilonitrila (SCC-ACN). Esses catalisadores foram caracterizados por difratometria de raios X (DRX) e espectrofotometria no UV-VIS. Os resultados mostraram que CuO, NiO e CeO2 são materiais nanocristalinos que apresentam estruturas e transições de transferência de carga características de óxidos de cobre, níquel e cério, respectivamente. O tamanho médio dos cristalitos está no intervalo de 3,2 e 20,7 nm. O CeO2 foi mais ativo para a SSC-ACN em menor temperatura que CuO e NiO. CeO2 e CuO produziram maior quantidade de N2 e todos os catalisadores produziram NOx, porém, esses foram obtidos em menor quantidade sobre CeO2. Desse modo, conclui-se que CeO2 foi o catalisador mais ativo e de menor produção de NOx na SSC-ACN. Palavras-chave: Acrilonitrila; oxidação catalítica; catalisadores; seletividade.

The Semicarbazone derivatives of 2-4, dihydroxy acetophenone is synthesized and characterized by physico‐chemical techniques such as melting point, Ultra Violet‐Visible Spectrophotometer, Fourier Transform Infra-Red (FTIR), proton nuclear magnetic resonance (1HNMR) spectroscopy and used as a chelating agent to form complex with Copper as Copper (II) semicarbazone derivative. The synthesised Copper (II) semicarbazone complex was also studied for its complex formation IR analysis, decomposition studies using TGA. The synthesised Copper (II) semicarbazone complex was successfully employed as precursor for synthesis of nano crystalline Copper oxide and its formation was confirmed by UV-Visible spectroscopy and XRD analysis. The method successfully employed use of Copper (II) semicarbazone complex for synthesis of nano Copper oxide.

Nanocrystalline pure Fe and Fe/MWCNT nanocomposites powders with 0.25, 0.5, 1, and 10 wt% MWCNT contents were synthesized by high-energy ball milling (HEBM). The as-milled powders were cold-compacted and annealed at 400 °C and 600 °C for 1 h in Ar atmosphere. The effect of ball milling on pristine MWCNT and Fe/MWCNT composite powders was also investigated as a function of milling time up to 20 h. The physical properties of MWCNT were imaged by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) before and after HEBM. The structural damage of MWCNT as a function of milling time and MWCNT content was studied using Raman spectroscopy. The structural characterization of MWCNT and Fe/MWCNT composites was conducted by X-ray diffraction (XRD) as a function of milling time, MWCNT content, and annealing temperature. The chemical properties of the synthesized composite powders were investigated using X-ray photoelectron spectroscopy (XPS). The microhardness test was performed to assess the effect of milling time, annealing temperature, and MWCNT content on the mechanical properties. The results indicated that after the ball milling process, the structure of MWCNT was destroyed, and the formation of the amorphous carbon phase was observed, which was confirmed by XRD and TEM analyses. In addition, decreased defect and carbon intensity ratios (ID/IG) were calculated from the Raman results with longer ball milling processes, which is attributed to the destruction of carbon bonds. The XPS results confirmed the presence of Fe C bonds as a result of the formation of carbide phases. A fine dispersion of precipitated carbides determined by TEM is found to promote the grain size stability below 100 nm in the nanocrystalline Fe matrix. The results from the micro-hardness tests showed that Orowan particle strengthening resulting from the carbide formation, as well as grain size hardening, is an important contributor to strengthening in Fe/MWCNT composites.

A well-designed procedure, including ion beam sputtering of aluminium (Al)–tungsten trioxide (WO3) composite films, annealing at an elevated temperature and dealloying of aluminium component, was carried out in sequence to fabricate porous nanocrystalline tungsten trioxide thin films. The texture, morphology and electrical and optical properties of the tungsten trioxide thin films were each characterised. It was found that when the annealing temperature of the aluminium–tungsten trioxide composite film reached 550°C, the obtained tungsten trioxide thin film after dealloying was nanocrystalline with a more pronounced porous structure. Electrical property tests showed that in contrast to that of amorphous tungsten trioxide films, the resistance of the porous nanocrystalline tungsten trioxide film was much greater, with a positive temperature coefficient of resistance (TCR) of +4.1 × 10−2/°C at temperatures of −10 to 5°C and a negative TCR of −2.4 × 10−2/°C at temperatures of 5 to 30°C. It was further demonstrated by ultraviolet–visible spectroscopy that compared with amorphous tungsten trioxide films, the porous crystalline tungsten trioxide film had much higher transmittance at the wavelength of visible light and a larger forbidden band width of 2.75 eV. Therefore, the porous nanocrystalline tungsten trioxide film exhibits unique or excellent electrical and optical properties, which indicate new potential applications in the fields of photoelectric devices and thermistors.

Molybdenum (Mo) impregnated g-C3N4 (Mo-CN) nanotubes are fabricated via a thermal/hydrothermal process to augment photoelectrochemical properties during solar-driven water-splitting (SDWS) reactions. Graphitic-C3N4 is an attractive material for photocatalysis because of its suitable band energy, high thermal and chemical stability. The FE-SEM and HR-TEM comprehend the nanotube-like morphology of Mo-CN. The spectroscopic characterization revealed bandgap energy of 2.63 eV with high visible-light activity. The x-ray diffraction of pristine g-C3N4 and Mo-CN nanotubes discloses the formation of triazine-based nanocrystalline g-C3N4, which remains stable during hydrothermal impregnation of Mo. Furthermore, Mo-CN nanotubes possess high sp2-hybridized nitrogen content, and metallic/oxidized Mo nanoparticles (in a ratio of 1:2) are impregnated into g-C3N4. The XPS analysis confirms C, N, and Mo for known atomic and oxidation states in Mo-CN. Furthermore, high photocurrent efficiency (~ 5.5 mA/cm2) is observed from 5%-Mo-CN nanotubes. That displays efficient SDWS by 5%-Mo-CN nanotubes than other counterparts. Impedance spectroscopy illustrated the lowest charge transfer resistance (Rct) of 5%-Mo-CN nanotubes, which further confirms the fast electron transfer kinetics and efficient charge separation resulting in high photocurrent generation. Hence, 5%Mo-CN composite nanotubes can serve as a potential photocatalytic material for viable solar-driven water splitting.

The present study focused on the preparation of microcrystalline cellulose (MCC) and nanocrystalline cellulose (NCC) from pineapple (Ananas comosus L.) leaves using chemical treatments followed by acid hydrolysis. Pineapple leaves could be used in medical applications such as drug delivery carriers. Advanced spectroscopy techniques such as Fourier-transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to analyze the physical, chemical, and morphological features of the isolated MCC and NCC; the results indicated the needle-shaped form of nanostructures with good purity and high crystallinity index of 75.00 and 76.38%, respectively. In addition, inhibition of the treated MRC-5 cells with all the samples revealed that the percentage of cell viability was less than 30%, which is an interesting finding given their role in the cytotoxicity effect of MCC and NCC. It appears that MCC and NCC derived from pineapple leaves have lower toxicity. As a result, the developed MCC and NCC can be used in pharmaceutical applications as a novel drug delivery system. Molecular docking was performed to understand the non-bonding interaction of cellulose with human acid-beta-glucosidase (β-Glc) (PDB: 1OGS). The docking result shows that cellulose unit docked within the active pocket of the enzyme by forming hydrogen bonds against ASN19, THR21, and VAL17 with distances of 2.18, 1.93, and 2.92 Å, respectively, with binding energy (−5.0 kcal/mol) resulting in close interaction of cellulose unit with the receptor.

Columbite-rich multiphase TiO2 nanoceramics with outstanding mechanical and dielectric properties were successfully prepared through high-pressure sintering by using anatase-type TiO2 as precursor. High-pressure sintering combined with phase transformation assisted consolidation can effectively refine the grain size of the recovered samples. This process is conducive to obtain nanocrystalline columbite-rich TiO2 ceramics with excellent performance. The highest hardness is approximately 12.76 GPa, which is 2.5 times higher than that of ordinary coarse-grained ceramics. The effect of columbite phase on the hardness of multiphase ceramics is discussed. The columbite-rich TiO2 ceramic shows a colossal permittivity (∼8 × 103) and low loss (∼0.2) at 1 kHz and room temperature, which are superior to that of undoped rutile polycrystalline ceramics. This ceramic shows a steadier frequency-dependent dielectric permittivity and loss than rutile TiO2 crystal. These results enrich the fundamental knowledge of columbite-rich TiO2, thereby enabling the exploitation of new applications.

In this work, a green Fe-doped TiO2 photocatalyst was successfully synthesized on Ti mesh through the chemical impregnation and anodization method. The influence of sample Fe-content on the photocatalytic performance was investigated in detail. Ordered TiO2 nanomesh was compactly decorated with nanospheres to form a novel photocatalyst Fe-doped TiO2 with anatase phase. Simultaneously, it exhibits higher light absorption intensity compared to the pristine TiO2 within the visible light range, and its absorption peak has a redshift. The VSM results showed that the sample has excellent magnetic properties. It is hard to achieve magnetic agglomeration after magnetic field removal, which benefits the strong recyclability and reusability of Fe-doped TiO2 photocatalyst. Importantly, this higher visible-light photoresponse of TiO2 was clearly obtained after Fe doping. When the Fe-content was 0.6 wt%, the degradation rate of methylene blue reached 87.9% under simulated sunlight irradiation for 2.5 h. The prepared nanocrystalline photocatalyst demonstrated excellent photocatalysis because of its prominent crystal morphology, strengthen light-absorption capacity, and commendable inhibition recombination of photo-induced electron-hole.

Color films are widely used for visual effect as well as for their functional properties. To date, however, synthesizing thin films with desired color remains challenging. In this work, AlN color films are deposited on Si wafers by precise control of the deposition time for different thickness during reactive magnetron sputtering from an Al target in Ar/N2 atmosphere. The thickness, morphology, structure, composition and color index are carefully examined by field emission scanning electron microscopy, atomic force microscopy, grazing incidence X-ray diffraction, X-ray photoelectron spectrometry and colorimeter, respectively. As the film thickness changes from 57 nm to 165 nm, the film exhibits purple, indigo, blue, green, yellow, orange and red in color. These colors repeat in the same order when the thickness goes over 165 nm. Once the thickness exceeds 467 nm, overlapping of colors takes place. The mechanisms are elucidated.

304L stainless steels with Hf additions were nanostructured by mechanical alloying (MA) and annealed at temperatures up to 1100 °C. The results showed that face-centered cubic (fcc) phase in 304L transformed to body-centered cubic (bcc) phase during MA. The in-situ studies revealed that bcc-to-fcc phase transformation completed after 105 min annealing at 900 °C for 304L, whereas Hf addition increased the required time and temperature for the complete transformation. The grain size of 304L stainless steel was ~10 nm after MA and remained ~167 and ~293 nm after annealing at 900 and 1100 °C, respectively, with Hf addition in comparison to 960 nm average grain size of base 304L stainless steel after annealing at 900 °C. The hardness of 304L increased from ~200 HV to 408 HV after MA and remained 329 HV after annealing at 1100 °C with Hf addition as opposed to 195 HV hardness of 304L.

Zinc tin oxide (ZTO) thin films can be deposited by atomic layer deposition (ALD) with adjustable electrical, optical and structural properties. However, the ternary ALD processes usually suffer from low growth rate and difficulty in controlling film thickness and elemental composition, due to the interaction of ZnO and SnO2 processes. In this work, ZTO thin films with different Sn levels are prepared by ALD super cycles using diethylzinc, tetrakis(dimethylamido)tin, and water. It is observed that both the film growth rate and atom composition show nonlinear variation versus [Sn]/([Sn]+[Zn]) cycle ratio. The experimental thickness measured by spectroscopic ellipsometry and X-ray reflectivity are much lower than the expected thickness linearly interpolated from pure ZnO and SnOx films. The [Sn]/([Sn]+[Zn]) atom ratios estimated by X-ray photoelectron spectroscopy have higher values than that expected from the cycle ratios. Hence, to characterize the film growth behavior versus cycle ratio, a numerical method is proposed by simulating the effect of reduced density and reactivity of surface hydroxyls and surface etching reactions. The structure, electrical and optical properties of ZTO with different Sn levels are also examined by X-ray diffraction, atomic force microscope, Hall measurements and ultraviolet–visible–infrared transmittance spectroscopy. The ZTO turns out to be transparent nanocrystalline or amorphous films with smooth surface. With more Sn contents, the film resistivity gets higher (>1 Ω cm) and the optical bandgap rises from 3.47 to 3.83 eV.

Present article discusses the role of plasma parameters on the morphology of nanocrystalline powders of lanthanum hexaboride (LaB6) synthesized by arc plasma gas-phase condensation method. The nanocrystalline powders so obtained were used to fabricate pellet-shaped cathodes of 5 mm diameter and thickness of 1 mm. Moreover, thermal plasma plume was used for sintering the cathodes and achieve desired densification. Prior to fabrication of cathodes, the synthesized powders of LaB6 were characterized using X-ray diffraction, Raman spectroscopy, and transmission electron microscopy to investigate phase purity and morphological properties. Finally, an indigenously developed thermionic emission experimental set-up was used to record thermionic emission current obtained from LaB6 cathode at different temperatures. Richardson Dushman equation was used to find out the work function of the cathode under investigation.

Grain boundaries (GBs) relaxation is a promising and effective strategy to improving GB stability or stabilizing nanocrystalline metals. However, previous studies mainly focused on nanocrystalline pure metals and GB behaviors therein, without considering the role of foreign atoms such as impurity or alloying atoms in GB relaxation. In this work, the shear-strain induced structural relaxation of pure Cu Σ3 [110](112) symmetric tilt GBs (STGBs), and the effects of foreign elements (Fe and Ni) and temperature on the GB relaxation were investigated in detail by molecular dynamics method. The results show that shear strain can trigger the structural relaxation of pure, Fe- and Ni-containing Cu GBs by the emission of Shockley partial dislocations from Cu GBs. Both Fe and Ni have impediment effects on the shear-strain induced GB relaxation, though the content of Fe or Ni atom (0.00165 at.%) is quite low in the GB model. The temperature cannot trigger GB relaxation independently within the considered temperature range, but play a positive role in the shear-strain induced structural relaxations of pure, Fe- and Ni-containing Cu Σ3 [110](112) STGBs. Our work might gain new insights into the mechanically induced GB relaxation in nanocrystalline copper and could be beneficial for improving the stability of Cu GBs.

X-ray diffraction, energy dispersive X-ray spectroscopy, and atom probe tomography (APT) were used to assess the phase homogeneity of bulk sintered (Cu, Co, Mg, Ni, Zn)O transition metal high entropy oxides (TM-HEOs) across multiple length scales. These three methods were applied to both coarse-grain and nanocrystalline TM-HEO samples sintered using two different processing routes. Coarse-grain samples were prepared by reaction sintering of unreacted nanopowders using conventional sintering, while nanocrystalline samples were prepared from solid-state synthesized nanopowders consolidated using spark plasma sintering. Despite the different processing methods and grain sizes, the TM-HEO samples exhibit little-to-no chemical or phase segregation across all length scales. Critically, APT confirms that there is no chemical segregation at the nm scale even after solid-state synthesis and high temperature consolidation.

This study demonstrates scalable mechanochemical synthesis of rhodostannite Cu2FeSn3S8 nanocrystals. On the contrary to the previous reports focused on the synthesis of stannite Cu2FeSnS4 reporting the rhodostannite impurity, we succeeded in preparing stannite-free product after milling. Pure elements were used for a solvent-free production in a batch of 100 g using an eccentric vibratory mill. The progress of the synthesis was monitored by X-ray diffraction and magnetometry, which both confirmed a successful reaction progress until 6 h of milling. However, further treatment (until 10 h) did not result in an improvement, as quite a high saturation magnetization (7.8 emu/g) and clearly evident diffraction at around 44° in the XRD pattern of the product due to the presence of ferromagnetic un-reacted iron with content slightly above 5% was evidenced. The product is sulfur- and tin-deficient, with crystallite size of around 12 nm. In-depth SEM/EDS analysis has shown the inhomogeneity of Fe distribution due to unfinished reaction. The bandgap of the produced material was 1.29 eV. The spark plasma sintering treatment resulted in complete consumption of non-reacted iron, but partial decomposition to stannite Cu2FeSnS4 was observed. The product is an intrinsic semiconductor with high electrical resistivity, and is therefore unsuitable for thermoelectric application. However, its thermal conductivity is low, thus it could be used as an electrically and thermally insulating material.