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Preparation and Characterization of Na<sub>2</sub>O-Y<sub>2</sub>O<sub>3</sub>-P<sub>2</sub>O<sub>5</sub>-SiO<sub>2</sub> Transparent Glass Ceramics
摘要： Transparent glass ceramics containing Na3.6Y1.8(PO4)3 crystals were successfully synthesized using high temperature melting quenching and subsequent heat treatment of the precursor glass with a composition 15Na2CO3-3Y2O3-45SiO2-31H3BO3- 5.4P2O5-0.6Sb2O3 (mol%). The impact of heat treatment is investigated in detail. The glass sample was tested by differential scanning calorimetry analysis to determine the heat treatment system. The ideal heat-treated condition is at 650°C for 2 h. The structure and morphology properties were systematically analyzed by recording X-ray diffraction patterns and scanning electron microscopy images, which indicate that Na3.6Y1.8(PO4)3 crystal were precipitated homogeneously among the glass matrix. The microstructural of precursor glass and glass ceramic were compared by analyzing FTIR spectra, indicating the formation of phosphate groups in glass ceramic. The refractive index of glass ceramics samples were measured. In the visible region, the transmittance of glass ceramics is up to 85%. Moreover, the relationship between the refractive index of the sample and the transmittance is discussed.
关键词： Na3.6Y1.8(PO4)3,glass ceramics,preparation,transparent
更新于2025-09-23 15:23:52
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Hydrothermal synthesis of tellurium nanorods by using recovered tellurium from waste electronic devices
摘要： Tellurium (Te) nanostructures with controlled morphology have received considerable attention in various applications owing to tunable optic, thermoelectric, photoelectronic, piezoelectric, and electrochemical properties. Herein, we introduce the cost-effective and eco-friendly synthesis of Te nanorods (Te NRs) from end of life electronic devices via hydrothermal methods. The Te NRs show the average diameter of 44.6 nm and a length of 358 nm in presence of polyvinylpyrrolidone, as a stabilizing agent. Moreover, the bismuth and intact p-type semiconductor (i.e., Bi0.5Sb1.5Te3) are selectively recovered as intermediated products. The Te NRs exhibit the NO2 gas sensing properties with concentration as low as 1 ppm at room temperature and fast response/recovery times of 1.59 and 2.10 s at 1 ppm, respectively. We believe that this powerful approach can be expanded to not only selective recovery of valuable materials but synthesis of various nanomaterials from waste electronic devices.
关键词： Recycling,Grain growth,Chemical properties,Powders: chemical preparation,Sensors
更新于2025-09-23 15:23:52
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Piezoelectric properties of a near strain-free lead zirconate titanate thin films deposited on a Si substrate
摘要： Chemical solution deposition (CSD)-derived near strain-free lead zirconate titanate (PZT) thin films on a Si substrate were prepared by designing a buffer layer structure. Strain-free PZT thin films with different compositions ranging from Zr/Ti = 50/50 to 58/42 were obtained to demonstrate lattice strain effects on piezoelectric properties. Results show that a near strain-free condition was attained with a SrRuO3 (SRO: 160 nm)/(La0.5,Sr0.5)CoO3 (LSCO: 90 nm)/LaNiO3 (LNO: 120 nm)/stacking structure, even on a Si substrate. The highest effective d33 value of the near strain-free PZT thin film was observed at 53/47 composition, which is the same as bulk materials, although the highest effective d33 value was obtained from 58/42 composition under the compressive lattice strain condition.
关键词： Chemical solution deposition,Piezoelectricity,Thin films,Multilayer structure,Lattice strain,Sol-gel preparation
更新于2025-09-23 15:22:29
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The influence on sample preparation on spectral induced polarization of unconsolidated sediments
摘要： Spectral induced polarization (SIP) measurements in the laboratory are in many cases intended to provide representative and comparable results of complex electrical conductivity. This is not invariably the case when using unconsolidated sediments, as the sample preparation influences several SIP-relevant properties of the samples, including the pore geometry. The pore space is supposed to control the polarization effect and therefore a change in the pore space will change the measured parameters. We analysed the influence of the sample preparation on SIP measurements by testing various filling methods, each defined by a sequence of particular steps, with regard to the reproducibility of the spectra. The measurements were performed on three different sample materials. Variations of the spectra due to different filling methods were obtained, indicating the importance of considering the sample preparation. Methods that improved the reproducibility compared to loose packing of the samples were found, but the most suitable packing procedure depended on the material properties. The mean relaxation times and normalized chargeabilities were obtained from a Debye decomposition. Although unidentified processes caused scattering of the measured parameters, a relation of the IP-parameters to the porosities was present. A decrease of the porosity reduced both the relaxation times and the normalized chargeabilities.
关键词： Debye decomposition,sample preparation,unconsolidated sediments,reproducibility,spectral induced polarization,porosity
更新于2025-09-23 15:22:29
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Control of 1-dimensionally structured tungsten oxide thin films by precursor feed rate modulation in flame vapor deposition
摘要： With the constant tungsten wire feed rate of 4 μm/s, the diameter of nanostructures increases with time and the multi-shell nanostructure and/or branched nanostructure eventually appears and grows. As the diameter and length of 1-D nanostructures increase with time, 1-D nanostructures are easily converted into multi-shell and/or branched nanostructures. The tungsten oxide vapor concentration and flame temperature also affect significantly this conversion of 1-D nanostructures. The increase of tungsten wire feed rate with time accelerated the appearance and growth of multi-shell and/or branched nanostructure, while the decrease of tungsten wire feed rate with time could help prepare the 1-D nanostructured WOX thin film without the growth of multi-shell and/or branched nanostructure. By the modulation of tungsten wire feed rate with time, the thin film thicker than 5μm with single shell nanotube structure could be prepared with almost no increase of nanotube diameter. For the preparation of longer 1-D nanostructured WOX thin film, it is found that the smooth decrease of wire feed rate with time, not the abrupt decrease of feed rate, is required in FVD process to prevent the multi-shell structure growth. We demonstrated that various attractive nanostructures can be prepared quickly by just changing precursor feed rate in FVD process for the first time. The results of this study can provide the basis for many practical applications of FVD process to fast fabrication of several interesting nanostructures.
关键词： nanostructure control,tungsten oxide thin film,precursor feed rate,preparation of 1-D nanostructure,flame vapor deposition
更新于2025-09-23 15:22:29
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Deterministic Joint Remote State Preparation of an Arbitrary Equatorial Three-Qubit State
摘要： We propose a new scheme for joint remote preparation of an arbitrary equatorial three-qubit state by using three three-qubit GHZ states as the quantum channel. In our scheme, eight different projective measurement basis vectors are needed. It is shown that the successful probability of our scheme is 100% by performing the appropriate unitary operations.
关键词： GHZ state,Three-qubit state,Joint remote state preparation
更新于2025-09-23 15:22:29
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Enhance the efficiency of green-yellow LED by optimizing the growth condition of preparation layer
摘要： The effects of the preparation layer grown under different conditions, which is an InGaN/GaN SLs structure inserted between the n-GaN layer and the MQWs, on the performance of green-yellow LED have been investigated. In this paper, the quality of InGaN/GaN multiple quantum wells (MQWs) and the optoelectronic properties of LED have been focused on. According to the experimental results, when the growth temperature of GaN barriers in SLs was increased, the interface between InGaN layers and GaN layers became more abrupt, and the indium distribution in the quantum wells became more uniform. In consequence, the forward voltage was reduced, the external quantum efficiency (EQE) was improved. By decreasing the growth rate of the high temperature barriers, the indium uniformity became even better, forward voltage was reduced again and EQE was further improved.
关键词： Preparation layer,Si substrates,Localized site,Crystal quality,Green-yellow LEDs
更新于2025-09-23 15:21:01
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Analysis of Yttria-Stabilized Zirconia by Inductively Coupled Plasma Atomic Emission Spectrometry
摘要： A method for determination of aluminum, hafnium, iron, yttrium, calcium, magnesium, and titanium by inductively coupled plasma atomic emission spectrometry (ICP-AES) is described. Conditions for the decomposition of two modifications of the analyzed material—unburnt and subjected to stabilizing firing—have been studied. It has been found that the unburnt zirconia dissolves in sulfuric acid, and the burnt sample can be converted to solution only by fusing with potassium pyrosulfate or potassium bifluoride. However, the application of these reagents leads to high values of the control experiment correction for trace impurities (at the level of tenths and hundredths of a percent). In this connection, we have studied the possibility of acid dissolution of the burnt sample under microwave decomposition, varying the qualitative and quantitative composition of the acid mixture, reaction temperature, and time to reach and maintain the required temperature. It has been found that the decomposition in the mixture of hydrofluoric and sulfuric acids (2 : 1) in the microwave system with stepwise heating of the reaction mixture ensures quantitative dissolution of the burnt sample and sufficiently low values of the control experiment correction for trace impurities. The analytical lines have been chosen taking into account their relative intensity, possible spectral overlaps, and the matrix effect in the analysis of model solutions containing 1.3 mg/cm3 Zr, 0.2 mg/cm3 Y, and from 0.2 to 20 mg/cm3 impurities. As a result, the following analytical lines have been chosen: Al II 167.079 nm and Al I 308.215 nm, Ca II 184.006 nm and 393.366 nm, Fe II 238.204 nm, Mg II 279.553 nm, Ti II 334.941 nm, Y II 371.030 nm, and Hf II 232.247 nm. The developed method for the analysis of yttria-stabilized zirconia by ICP-AES allows simultaneously determining aluminum, iron, magnesium, and titanium in the range of 0.01–1.0%; calcium, 0.02–1.0%; hafnium, 0.1–5.0%; and yttrium, 2.0–15% with a relative standard deviation of 6–30 rel % (for Al, Fe, Mg, Ti, and Ca), 2–7 rel % (Hg), and 2–4 rel % (Y). The correctness of the method is confirmed by the standard addition technique.
关键词： zirconium dioxide stabilized by yttrium dioxide,inductively coupled plasma atomic emission spectroscopy (ICP-AES),microwave sample preparation
更新于2025-09-23 15:21:01
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Development of metal matrix composites by laser-assisted additive manufacturing technologies: a review
摘要： Metal matrix composites (MMCs) generally possess superior properties than the monotonic matrix alloys, and thus, they have become excellent candidate materials in various applications. Also, the ability of property tailoring at an affordable cost is of particular importance to industries. Among the many manufacturing techniques for MMCs, laser-assisted additive manufacturing (AM) techniques have emerged and drawn increasing attention in the past decade. In the literature, a wealth of studies have been carried out on the synthesis of MMCs via laser-assisted AM techniques, as well as the property evaluation of the obtained MMCs. In this paper, we review and analyze the relevant literature and summarize the material preparation, optimization of process parameters, resultant improvements, and corresponding strengthening mechanisms for each major category of MMCs. Moreover, the limitations and challenges related to MMC synthesis using the laser-assisted AM techniques are discussed, and the future research directions are suggested to address those issues.
关键词： Laser-assisted additive manufacturing,Process parameters,Material preparation,Strengthening mechanisms,Metal matrix composites
更新于2025-09-23 15:21:01
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A Benchmark of 300mm RP-CVD Chambers for the Low Temperature Epitaxy of Si and SiGe
摘要： we have assessed, in 300 mm Reduced Pressure – Chemical Vapour Deposition chambers from major suppliers, the advantages and drawbacks of disilane for the low temperature growth of Si and SiGe. Si growth rates are, for T < 575°C, approximately ten times higher with Si2H6 than with SiH4, which are in turn roughly ten times higher than with SiH2Cl2. For given GeH4 and Si precursor mass-flow ratios, lower Ge contents and much higher SiGe growth rates are obtained at 550°C, 20 Torr with Si2H6 than with SiH4 and especially SiH2Cl2. Growth rates (Ge concentrations) are with SiH4 and SiH2Cl2 lower (slightly lower) in Supplier A than in Supplier B chamber. The situation is the opposite with Si2H6. This is assigned to (i) a ~ 5°C offset between the two and (ii) effective precursor flows which are different, most likely due to chamber geometry differences. Growth rate activation energies and relationships linking Ge concentration to precursor mass-flow ratios are quite similar, however, making process transfer between the two rather easy. Finally, we have compared ex-situ “HF-Last” wet cleanings and in-situ surface preparation processes for Si surface conditioning prior to epitaxy. Surfaces are after the latter always under high purity N2. This results in a threshold H2 bake temperature (above which there is no O interfacial contamination anymore) which is shifted downwards by ~ 25°C (from 775°C down to 750°C). Below that threshold, O sheet concentrations are with in-situ processes typically one third those associated with “HF-Last” wet cleanings and epitaxial surfaces are smoother.
关键词： surface preparation,SiGe,silane,disilane,RP-CVD,low temperature growth,Si,dichlorosilane
更新于2025-09-23 15:21:01