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Ferroelectric ceramics display a remarkable photostriction effect, which could facilitate the prevention of electromagnetic interference and promote the integration and miniaturization of actuator systems, indicating potential applications in glimmer sensors. In this work, highly transparent La-doped 0.9Pb(Mg1/3Nb2/3)O3-0.1PbTiO3 (0.9PMN–0.1PT) ceramics were synthesized using a solid-state reaction method in an oxygenated atmosphere. XRD and SEM were used to analyze the phase structure of the dense samples, which displayed a pure perovskite structure, with no trace of a pyrochlore phase. With La doping, the phase transition temperature shows a decreasing trend, and its dielectric constant could reach up to 20,000. The P-E loop of the samples was gradually refined into a straight line with an increase in the doping amount. After La doping, the transparency of the 0.9PMN–0.1PT ceramics was significantly enhanced and reached up to 61% at the near-infrared band. Finally, the photogenerated voltage and deformation of the La-doped 0.9PMN–0.1PT ceramics were investigated under ultraviolet light of various intensities. After 20 s of irradiation at an intensity of 800 mW/cm2, the maximum voltage and deformation, with values of 40 V and 250 nm, respectively, were both found in the 1%La-doped 0.9PMN–0.1PT ceramics. [ABSTRACT FROM AUTHOR]

We report the structure, microstructure, dielectric, and transport properties of the dysprosium (Dy) modified lanthanum bismuth oxide (LaBi0.85Dy0.15O3) synthesized by the solid-state reaction method. The Rietveld refinement of the X-ray diffraction (XRD) data was done using MAUD software which adopts an orthorhombic crystal system. Scherer's formula was used to calculate crystallite size, which is found to be 25.2 nm. An analysis of a scanning electron microscope (SEM) image indicates that the grains have an even distribution throughout the whole sample surface with well-defined grain boundaries. Once more, compacted grains and clearly defined grain boundaries may have an impact on the conduction mechanism in the sample. The energy dispersive analysis of the X-ray (EDX) spectrum provides that all the constituent elements are present in the both weight and atomic percentage in the sample. The generated sample appears to reflect the Maxwell–Wagner type of dielectric dispersion, in accordance with research on the dielectric characteristics as a function of temperature and frequency. While impedance evaluation confirms the existence of the negative temperature coefficient of resistance (NTCR), the modulus plot analysis indicates a non-Debye kind of relaxation mechanism. A thermally activated conduction mechanism is present, according to the study of the ac conductivity plot. Again, the study of the Nyquist and Cole–Cole plots shows that semiconducting behavior is consistent with several applications involving energy storage devices. [ABSTRACT FROM AUTHOR]

Transparent wood-based materials show great potential for energy-efficient housing and construction due to their ideal optical performances, good mechanical strengths, and low thermal conductivity. However, it still remains a great challenge to fabricate UV-blocking and strong transparent wood-based materials with isotropic optical and mechanical properties, mainly due to the natural anisotropy of wood. Herein, we describe a facile strategy to prepare transparent wood-based biocomposites by integrating delignified wood particles with poly(vinyl alcohol) (PVA) impregnation prior to the compression treatment. This method enables biocomposites to show desirable isotropic optical and mechanical properties, easily tunable high wood component percentage and UV-blocking ability. The enhanced interfacial bonding between wood particles and PVA polymer, together with a similar refractive index, synergistically contributes to excellent performance. The resulting biocomposites (approximately thickness of 1 mm) possess isotropic optical and UV-blocking properties and have a maximum optical transmittance of 62%. The highest tensile strength and flexural strength can reach 86.8 and 158.8 MPa, respectively. Moreover, they display low thermal conductivity (0.38–0.42 W m−1 k−1) and suitable thermal stability. Therefore, this study provides a new method to optimize the properties of transparent wood-based materials for utilization in energy-saving building fields. [ABSTRACT FROM AUTHOR]

We have fabricated (Sr1-xMgx)TiO3, (x = 0.00 & 0.3) sintered ceramics by mixed oxide route and studied the structural and microwave dielectric property of the samples with respect to variation of frequency (1 GHz to 2 GHz) using Impedance spectroscopy. This study revealed that the XRD patterns shown cubical structure along with space group (Pm-3m) while SEM images shown spherical like grains of the samples. The microwave dielectric properties of the samples vary with Mg2+ dopants and operating frequency as well. The distinctive absorption peak of hydroxyl vibration at 1350 cm−1 was observed for both samples while hydroxyl vibrational mode was also observed only in doped sample at 3000 cm−1. The microwave dielectric properties strongly depend upon Mg2+ contents and resonating frequency. The optimum microwave dielectric properties have been recorded which may help for the application of microwave wireless communication devices. [ABSTRACT FROM AUTHOR]

In this paper, a new counter-propagation waves coupling mechanism is proposed which is expected to realize an electromagnetically induced transparency (EIT)-like effect. Comparing the travelling waves coupling mechanism (see J. Mod. Opt. 2015,62:313-320 [9]) with the counter-propagating waves coupling mechanism, we find out that the transparency window breadths of transmission spectra are greatly enhanced and the corresponding phase shift spectra possess a flat profile or a square profile. Our numerical simulated results are in good agreement with the theoretical analysis. The EIT-like effect can significantly reduce the group velocity near the edge of the square profile transparent window. We believe that the counter-propagating waves coupling mechanism is particularly beneficial for the realization of active manipulation of slow light devices (such as delay lines) required in the conventional EIT scheme. In the vicinity of the transparency peak, we can obtain a large group delay, may gain more significant potential applications in slow-light transmission and optical storage. [ABSTRACT FROM AUTHOR]

The fogging of the optical lenses seriously affects the life quality and safety, which is due to the gathering of the humid air into liquid droplets on the solid surface because of the temperature change. Superhydrophobic coating modification is an effective way to repel the water from surface. However, due to the specific application requirements, the transparency of optical lenses after coating modification is still the challenge for the application of such superhydrophobic coatings. In this work, a superhydrophobic and transparent surface coating was fabricated by the layer-by-layer self-assembly followed with fluorination. After poly(sodium 4-styrenesulfonate) and poly(allylamine hydrochloride) (PAH) multilayer precoating was generated on the surface, the different bilayers of SiO2 nanoparticles in different particle sizes and PAH multilayers were fabricated. The obtained polyelectrolytes-nanoparticle multilayers were fluorinated by a fluorinating agent. Such polyelectrolytes-nanoparticle multilayered coating renders obvious micro-nano composite structure, showing excellent superhydrophilicity, whereas such coating modified eyeglasses keeps excellent light transparency. The results of antifogging and defogging test also proved that the eyeglass modified with this coating had good antifogging and defogging performance. Therefore, such polyelectrolytes-nanoparticle multilayered coating with excellent superhydrophobic and transparent properties might provide a feasible approach for the practical antifogging application of optical lenses. [ABSTRACT FROM AUTHOR]

Acoustic emission (AE) measurement has been used to investigate microscopic failures and damage progress in carbon fiber reinforced plastics (CFRP). In this work, AE measurements were conducted on plain-woven CFRPs fabricated by vacuum-assisted resin transfer molding process and neat epoxy resins during tensile tests to evaluate the failure modes. Four types of epoxy resins were used as matrix resins to investigate the effects of matrix resin characteristics on the microscopic damage behavior and the mechanical properties of CFRP. As a result, the mechanical properties of on-axis CFRP were comparable regardless of matrix resins. On the other hand, in the case of off-axis CFRP, such as 45° direction, the tensile strength was remarkably lower with a brittle matrix resin. From the AE measurement results, the number of cumulative hits for CFRP was much larger than that for neat resins due to the occurrence of fiber/matrix interfacial cracks. Also, AE waves for CFRP had a longer duration than that for neat resin, and the relationship between the degree of duration and fracture mode was clarified. [ABSTRACT FROM AUTHOR]

Porous Mo2TiAlC2 ceramics with different Al content in nominal compositions were fabricated through powder metallurgy technique of Mo, Al, and C elemental powders and TiH2 powders, which were carried out in vacuum environment. Systematic experimental results revealed that the pore structure of these Mo2TiAlC2 ceramics were affected by different Al content significantly. With ascending Al content changed from 0.9 to 1.3 mol, pore sizes and viscous permeability coefficients of these test specimen substantial reduce while volume demonstrated an ascending tendency, the phase is mainly Mo2TiAlC2, and the secondary phase Mo3Al2C decreased with the increase of Al content, and the reason for deviation of molar mass was attributed to the volatilization of Al. When the Al content continues to rise to 1.7 mol, the pore structure parameters including pore sizes, viscous permeability coefficients, and porosities increased, and the impurity phase appeared. Besides, evolution of pore structure parameters in sintering stage and the pore-forming mechanism was explored. The present work is of momentous significance in the preparation of quaternary and multi-element porous MAX phases ceramics/alloys. [ABSTRACT FROM AUTHOR]

The glass crystallization method was used to synthesize a nanocomposite material consisting of crystallites inside a glass-like matrix. In this study, we have studied the structural, optical, dielectric, and ferroelectric properties of crystals embedded in a glassy matrix. The melt quenching technique was used to prepare the Ba0.7Sr0.3TiO3 (BST) –Na2O–B2O3-SiO2 system. The heat treatment technique ranging between 650 and 800 °C were used to change the prepared glass to glass-ceramic samples. The presence of the amorphous phase and the crystalline precipitation phase in the amorphous matrix were showed in the X-ray diffraction patterns. The scanning electron microscope was used to study the morphology of the crystals. All glass-ceramic samples confirm the spherical-like nanocrystals structure. It was found that while the heat treatment temperature increased, the crystal size and crystallinity increased. The optical, dielectric, and ferroelectric properties of the synthesized samples depend upon their morphology and crystallinity. [ABSTRACT FROM AUTHOR]

The indirect method of obtaining in situ particle velocity of sample, under dynamic high-pressure loading experiments, generates an error due to the influence of rarefaction wave from the sample-window interface. Using the spinel as a window is an attractive method to reduce the error due to the total impedance matching of sample and window in the loading experiments of the spinel. To explore the possibility of the spinel as a window, ramp wave compression experiments were conducted to determine the refractive index of loading longitudinal stress range below 15.9 GPa. The result showed smooth particle velocity curve and linear relationship between refractive index and density. The effect of temperature on refractive index can be negligible, proved by analyzing the effect of temperature on polarizability. It is indicated that the spinel can be used as a window for loading experiments of the spinel and similar impedance materials. [ABSTRACT FROM AUTHOR]

We fabricated Tl-doped NH4Cl transparent ceramics using SPS method with varying Tl concentrations (0%, 0.01%, 0.05%, 0.1%, 0.5%, and 1%) and evaluated the properties of photoluminescence (PL), radioluminescence (RL), and optically stimulated luminescence (OSL). In PL and RL spectra, Tl-doped samples exhibited two emission peaks at around 380 and 530 nm due to the 3P1→ 1S0 transitions of Tl+ and the off-center self-trapped excitons near Tl+, respectively. In the OSL spectra, Tl-doped samples exhibited an emission peak at around 350 nm due to the 3P1 → 1S0 transitions of Tl+. In the OSL dose–response function, all the samples showed a good linearity over a range of 10–10,000 mGy. [ABSTRACT FROM AUTHOR]

Lu2(Ti1-xHfx)2O7 (x = 0–0.5) transparent ceramics were fabricated by reactive spark plasma sintering using commercially available Lu2O3, TiO2 and HfO2 powders. Effect of Hf content x on the phase evolution, microstructure, density, transmittance and electrical conductivity of the resulting ceramics were investigated. Lu2(Ti1-xHfx)2O7 transparent ceramic had a pyrochlore structure in the range of x = 0–0.3, while preserved a defect-fluorite structure at x = 0.4–0.5. The lattice parameter and theoretical density increased linearly with increasing Hf content x. The average grain size decreased at x = 0–0.3 and kept almost constant at x = 0.4–0.5. All the samples exhibited a dense microstructure and the highest in-line transmittance was 57% at 550 nm at x = 0. The highest bulk conductivity was 1.7 × 10−2 S m−1 at 1073 K for Lu2(Ti0.8Hf0.2)2O7, with an activation energy of 1.16 eV. [ABSTRACT FROM AUTHOR]

In this study, hydroxyapatite powder Ca10(PO4)6(OH)2 (HAp) doped with gadolinium (Gd3+) (HAp:Gd3+) in different mole percentage of between 0.1 and 1.6 was synthesized by sol−gel method at 900°C. The reaction was carried out by hydrolysis of Ca(OH)2 and DCPD (CaHPO4.2H2O) in aqueous solution and then analyzed through XRD, SEM, FTIR, TGA and Four-Point Probe method (custom-made). The results show that Gd3+ has been successfully doped into the hydroxyapatite structure. Then, the photoluminescence, thermal and electrical properties of pure and Gd3+ doped hydroxyapatite were studied and compared with the pure hydroxyapatite. In conclusion, the emission band of Ca10-xGdx(PO4)6(OH)2 was observed at 263, 278, 294, 312 nm) under excitation with 185 nm. The Stokes shift of HAp:Gd3+ was calculated to be 16.031 cm−1. On the other hand, the electrical and thermal conductivity of HAp increased with the increase in Gd3+ concentration due to Ca2+ cation vacancies caused by Gd3+doping. [ABSTRACT FROM AUTHOR]

Influences of TiO2 or Y2O3 dopants on pressure-assisted sintering of polycrystalline Al2O3 were investigated to control the microstructure of sintered Al2O3 as well as to improve the homogeneity of transparent Al2O3 samples. The transparent polycrystalline Al2O3 samples with and without the dopants were fabricated by two-step pulsed electric current sintering (TS-PECS). By the grain boundary segregation by the dopants, both TiO2 and Y2O3 depressed the densification and grain growth processes during the sintering of polycrystalline Al2O3. The principle originalities of this work include the relationship between the homogeneities of microstructure and of optical transmittance of large-size polycrystalline Al2O3 and the consequent doping strategy for controlling of homogeneity of transparent polycrystalline Al2O3 prepared by two-step PECS. Doping of Y2O3 dramatically reduced the grain size of polycrystalline Al2O3 and improved its optical transparency. The homogeneity of the microstructure and the optical transparency of the large-sized polycrystalline Al2O3 with 0.1 mol% Y2O3 was improved. The addition of TiO2 also slightly retarded densification and reduced the grain size of the sintered Al2O3 samples. However, TiO2 dopant is not good for applications of transparent Al2O3 because it caused a dark color in transparent polycrystalline Al2O3 samples by uncertain reasons. [ABSTRACT FROM AUTHOR]

Electrospinning and silver mirror reaction (SMR) were combined to synthesize silver nanowire membrane. The best sheet resistance (Rs) and transmittance (T) values reach around 15 O/sq and 80% on PET, 37 O/sq and 81% on glass, respectively. In this method, Poly (acrylonitrile - co - phenylethylene) (P(AN-S)) nanofibers act as the templates and reduction of silver on the nanofibers surface act as seeds. In SMR process, silver deposited on the surface of nanofibers and developed into silver nanowires. The membrane was characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The effects of spinning parameters and silver mirror reaction time on membrane properties were investigated. This process is easily controlled and it takes place at ambient condition, which gives a new opportunity for transparent conducting flexible electronics. [ABSTRACT FROM AUTHOR]

We measured the time dependence behavior of the dielectric permittivity of lead lanthanum zirconate titanate (PLZT) transparent ceramic sample and a single-crystal lead magnoniobate (PMN) from the moment of the field application at certain temperatures after the zero-field cooled regime. The delay time of the phase transition from the glasslike state to the field-induced ferroelectric state was determined from the sharp change in the dielectric permittivity in PMN single crystal. The same transition in PLZT has more smooth behavior. We found the temperature dependence of the delay time of the phase transition under ultraviolet illumination for PMN single crystal. [ABSTRACT FROM AUTHOR]

γ-Al2O3 nanoparticles (NPs) with a mean diameter of 60 nm were prepared through the sol–gel technique and characterized by X-ray diffraction, field emission scanning electron microscopy (FESEM), and ultraviolet–visible (UV-Vis) spectroscopy. The formation of cubic structures with the γ phase for Al2O3 NPs confirms. The average particle size obtained is about 60 nm by the FESEM image. The nonlinear optical properties were examined by a single-beam Z-scan method using a Gaussian visible continuous wave Nd:YAG laser (532 nm). The Z-scan findings indicated a self-focusing nonlinearity and saturable absorption process in order of 10−8 (cm2/W) and 10−4 (cm/W) in the synthesized γ-Al2O3 NPs, respectively. Moreover, Kramers–Kronig relations were applied to determine the complex refractive index and dielectric coefficient of the specimens by Fourier-transform infrared spectroscopy. The transversal and longitudinal optical (TO and LO) modes are the two intersection points in the real and imaginary parts of the complex refractive index. Also, the maximum position of the Im(−1/ ε) plot is related to LO frequency. [ABSTRACT FROM AUTHOR]

Highly transparent lead-free ceramics of La-doped KNN based were synthesized by conventional solid state reaction method and ordinary sintering process for the first time. The optical and electrical properties of the KNN based lead-free transparent ferroelectric ceramics were investigated in this work. The transparent ceramics exhibited a transparency as high as 60% for the infrared wavelength. Meanwhile, the electrical properties of the ceramics still maintained relatively high levels (d33 = 55 pC/N, Tc = 402 °C), suggesting that it should be a novel and promising lead-free material that used in a large variety of electro-optical devices. [ABSTRACT FROM AUTHOR]

CaxBa1-xNb2O6 (CBN) ceramics with tetragonal tungsten bronze (TTB) structures are very attractive from academic and technological fronts due to their stupendous ferroelectric properties. Polycrystalline samples of CaxBa1-xNb2O5 were prepared by a high temperature solid state reaction technique. The phase formation, microstructure and optical properties of the prepared samples were investigated by X-ray diffraction, scanning electron microscope and Raman spectrometer, respectively. X-ray analysis confirms the partially filled tetragonal tungsten bronze (TTB) structure. Scanning electron micrographs provide information related to the morphology and grain size distribution of the samples. Detailed analysis of the structural and optical properties suggests that these samples have undergone a phase transition well above the room temperature. [ABSTRACT FROM AUTHOR]

Nanostructured precursors of yttria-alumina garnet powders have been synthesized using the glycine–nitrate technique. It was shown that the main characteristics of the powders are determined by the glycine/nitrate (G/N) molar ratio in the initial solution and the temperature of the heat treatment of the precursors. The maximum specific surface area of the powders was obtained for the G/N ratio of 0.4. Subsequently, the powders were subjected to mechanical treatment and sintering. The effects of the treatment conditions and the amount of the sintering additive (Sc2O3) on the properties of the resulting ceramics were studied using erbium-yttrium garnet (Er1,5Y1,5Al5O12) as an example. Ceramics with a transparency of approximately 70% were obtained at 1790°С. [ABSTRACT FROM AUTHOR]

In this article, we determine the impact of laser parameters on the development of a flexible conductive transparent film in multi wall carbon nanotubes (MWCNTs) regular structures fabricated on the PET substrate. Both MWCNT and PET are the attractive material for flexible electronics and technological interest in Micro/Nano-manufacturing. Now day, femtosecond laser irradiation nanojoining with selected surface treatments is introduced as an interface enhancer between MWCNT and the PET. We investigated the femtosecond laser of fused PET. After laser irradiation heating, thermal effects modify the structures, and the properties of MWCNTs at the junction point. The network created by Laser irradiation requires extreme parameters: Laser energy irradiation, the effective laser radius, and preheating temperature. Theoretical calculations show us that 90 mW under laser spot radius of 1.5 mm and preheating temperature of 300 K can generate 433.0845 K as surface temperature enough to connect 1 µm in thick of MWCNTs without damage the PET substrate. [ABSTRACT FROM AUTHOR]

The time dependence behavior of the dielectric permittivity of lead lanthanum zirconate titanate transparent ceramic sample from the moment of the field application at certain temperatures after the zero-field cooled regime is compared to that exhibited by a single-crystal lead magnoniobate. The delay time of the phase transition from the glasslike to the field-induced ferroelectric state was determined from the sharp change in the dielectric permittivity in a lead magnoniobate single crystal. The same transition in lead lanthanum zirconate titanate has more smooth behavior. In the case of ultraviolet illumination, the delay becomes a few times shorter for both cases. [ABSTRACT FROM AUTHOR]

Cathode ray tube (CRT) glass contains significant amounts of alkali and alkaline earth oxides, making it a useful by-product for use in the ceramics industry. Among the various alkali oxides present, those of strontium (SrO), calcium (CaO), and magnesium (MgO) are well known flux materials used widely in the ceramics industry. The most effective flux, SrO, is also a limited resource. In this study, we aimed to develop an environmentally friendly, low-cost method for recycling CRT waste by using it to produce transparent ceramic frits on an industrial scale. Four different samples were fabricated containing between 13 and 25 wt.% CRT panel glass. The color values, sintering behaviors, phases, and microstructural properties of the corresponding samples were analyzed and compared. The results indicate that a composition containing 25 wt.% CRT panel glass could pass the ISO 10545 test. Thus, the results confirm that CRT glass can be used to inexpensively produce transparent ceramic frits at an industrial scale. Implications: The recycling of electronic waste (e-waste), including CRT waste, has increased by high rates of computer and TV consumption. This increase in consumption is likely to increase the rate at which CRTs are discarded. However, CRTs cannot be recycled in the desired amount. Owing to the high silicate, barium and strontium content of CRTs, it has great potential for glass ceramics such as frits. CRT panel glass to produce commercial transparent frit at low cost through an industrial production route for use in single-fire sintered products. Thus, CRT wastes can be recycled cost-effective, sustainable and environmentally friendly. [ABSTRACT FROM AUTHOR]

A cholesteric liquid crystal (CLC) – cholesteryl tridecylate (X-20) was doped with nanoparticles of shungite carbon (Sh) to effectively improve some physicochemical properties of the CLC matrix for the further use in electronic devices. The influence of Sh (concentration of 0.005 and 0.02 wt. %) on phase transition temperatures of X-20 was studied. Addition of 0.005 wt. % of Sh shifts phase transition temperatures upward, while the concentration increase to 0.02 wt. % leads to the opposite effect. These data were taken into account during the study of dielectric properties in different phase states. The dielectric properties were studied in the frequency range from 20 Hz to 10 MHz. Only for the system X-20/Sh (0.02 wt. %), dispersion of the dielectric permittivity was observed. The dispersion was caused by the appearance of additional relaxation processes and it was substantially more extended than the classical Debye theory suggests. The results of the research show that the 'CLC – Sh nanoparticles' composites can be used as promising materials to increase the efficiency of radio electronics devices. [ABSTRACT FROM AUTHOR]

Spray drying technology is a suitable process applicable for large-scale production of various advanced materials. Recent laboratory scale research focuses on the development of (1) nano/microstructured electrode materials for next-generation lithium ion batteries with enhanced cell capacity and superior electrochemical performance, (2) transparent materials for laser ceramics, and (3) bioceramics, such as bone substitutes, dental implants, and cements with improved bioactivity and therapeutic effects. This paper reviews the current research progress in these application fields and highlights the importance of laboratory scale spray drying in the corresponding advance materials processing routes. [ABSTRACT FROM AUTHOR]

The main objectives of the paper were to study the anomalies in the electrophysical parameters of the transparent ferroelectric ceramics of the PLZT (X/65/35) system near the diffuse phase transition, and to measure the complex sets of dielectric, elastic and piezoelectric parameters of those materials over a wide frequency range. The ferroelectric ceramics of the system (Pb1-xLax)(Zr0,65Ti0,35)O3 with lanthanum content were chosen as the object of the study. The experimental samples of ferroelectric PLZT ceramics were obtained by the hot pressing method. The complex parameters of the experimental samples were measured by the piezoelectric resonance analysis method using the software package PRAP. The sets of complex elastic, dielectric and piezoelectric parameters of PLZT (6.5/65/35) ceramics were obtained. The anomalies in the behavior of surface acoustic waves velocity and attenuation for PLZT (7.5/65/35) ceramics near the temperature of diffused phase transition were found and discussed. [ABSTRACT FROM AUTHOR]

Characteristics of ZrO2polycrystalline ceramic foam catalyst including crystal structure, phase composition, and microstructure were analyzed by Py-IR, XRD, SEM, and BET. Effects of preparation conditions such as calcination temperature, calcination time, ZrO2(catalyst matrix), Al2O3(flux), TiO2(stabilizer), NaHCO3(low-temperature pore-forming agents), and NaCl (high-temperature pore-forming agents) on catalytic activity were investigated. The optimum composition of ZrO2polycrystalline ceramic foam catalyst were optimized using response surface methodology (RSM) to be 88.47% ZrO2, 9.62% Al2O3, 3.31% TiO2, 10% NaHCO3, and 25% NaCl (compared with the standard number 100). After calcination at 1550°C for 120 min, fatty acid methyl ester conversion rates were substantially maintained at around 97.31%, The FAME content in the product oil exceeded 97% after five successive reuses of the catalyst. In addition, catalytic activity did not significantly fluctuate. The proposed catalyst presents a new type of solid catalyst with excellent catalytic activity and stability. [ABSTRACT FROM AUTHOR]

(Gd1-xYbx)3Al5O12 (x = 0.1, 0.2, 0.3) transparent ceramics were prepared by solid state reaction. The stability of (Gd1 − xYbx)3Al5O12 garnet phase is strongly affected by amount of Yb and the sintered temperature. At 1550°C, 10% Yb substitution is enough to get stable garnet phase, while at 1650°C, it needs 17% Yb substitution. The transmittance of transparent ceramics is larger than 60% at 800 nm. For (Gd1 − xYbx)3Al5O12 transparent scintillators, the activators for doping should have longer emission wavelength. [ABSTRACT FROM AUTHOR]

The polycrystalline sample of BaTi0.95Ge0.05O3was prepared by solid-phase reaction using a conventional method. The morphology of investigated sample was characterised by scanning electron microscopy (SEM). The results allowed to determining the stoichiometry of the material and evaluate their microstructure. High quality samples were investigated, the grains are well shaped without of a glassy phase. The dielectric properties of the BaTi0.95Ge0.05O3ceramics were determined. The results were compared with these ones obtained for pure BaTiO3. The obtained data indicated that the substitution of Ge+4ions had an influence on the values of the real (ϵ′) and imaginary (ϵ″) parts of electric permittivity. [ABSTRACT FROM PUBLISHER]

Dense KSr2Nb5O15(KSN) ceramics with a duplex structure was successfully prepared using acicular KSN particles as raw materials. It was suggested that the preparation of dense ceramics by adjusting abnormal grain growth was feasible absolutely. The effect of a duplex structure on the electric properties and optical behaviors were investigated. The results indicated that the specimen with the duplex structure had a strong frequency dispersion of dielectric constant. The optical transmittance of the specimens with a duplex structure was higher than that of grain normal distribution, which also gave a new method on the study of the optical ceramics. [ABSTRACT FROM AUTHOR]

Graphene oxide nanosheets have been successfully synthesized through a modified Hammer's method by oxidation of pure natural graphite powder. The crystallinity, structure and morphology of the as-synthesized product were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectrophotometry, Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). XRD and FTIR were performed to verify the structure of the synthesized graphene oxide. The analysis results revealed the presence of oxygen-containing groups in the as-synthesized graphene oxide nanosheets. Additionally, SEM and TEM images revealed the graphene oxide nanosheets synthesized by exfoliation of graphite were very thin layers with transparency and similar to wrinkled and crumpled silk veils. [ABSTRACT FROM AUTHOR]

The methods of laser welding of plastic materials, equipment, technologies for joining various transparent plastics and also hybrid technologies of laser welding of plastics are analysed. [ABSTRACT FROM PUBLISHER]

Crystal and transparent ceramics have been considered to be a new generation of materials with a very important role in secure and economic sustainable development. In this paper, the advantages and disadvantages among highly crystalline transparent glass ceramics, crystals, and ceramics have been compared, including their chemical composition, preparation technology, and the equipment requirement of the materials. Based on the author's knowledge and understanding, the possibility of highly crystalline transparent glass ceramics substituting for crystals or ceramics has been discussed. The present situation and newest progress in the research of highly crystalline transparent glass ceramics have been introduced. The attractive opportunities and difficult challenges in this research direction are shown in this article. In particular, this paper focuses on some ideas from the author, rather than a simple introduction to the existing situation and research progress of transparent materials. [ABSTRACT FROM AUTHOR]

High transmittance of Nd-doped YAG transparent ceramics were synthesized by a traditional solid-state reactive sintering method. The crystalline and the optical properties of the samples were investigated. The results show the relative density and transmittance of Nd-doped YAG ceramics depended on the sintering time and temperature. The maximum transmittance of Nd:YAG ceramics is above 90%. All the transparent Nd:YAG ceramics present a main emission peak at 1064.5 nm, which is in accord with Nd:YAG single crystal. [ABSTRACT FROM AUTHOR]