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Temperature Dependence of the Lattice Parameters of Cu2?–?xSe (0.03 ≤ x ≤ 0.23) Powders Fabricated by Mechanochemical Synthesis
摘要： The Cu2 – xSe (0.03 ≤ x ≤ 0.23) powders fabricated by mechanochemical synthesis have been studied by X-ray diffraction. The in situ study has been carried out for the temperature dependences of the lattice parameters, the structures, and the phase compositions of the powders in the temperature range 25–350°C. The powder compositions are shown to differ from the charge compositions and are shifted to lower copper concentrations. The estimation of peak half-widths of the cubic β phase indicates an increase in the structure imperfection after the phase transition from the α phase to the β phase of Cu2 – xSe at ~140°C. It is shown that the superpositions of the subtraction solutions (copper vacancies) and interstitials solutions (copper atoms in interstitial sites), whose proportion is changed as a function of temperature and the deviation from stoichiometry, are in the thermodynamic equilibrium in the copper selenide solid solution at room temperature. The change in the slope of the dependence of the lattice parameter of the powder Cu2 – xSe samples on the composition (0.03 ≤ x ≤ 0.23) in the temperature range 25–350°C enables the suggestion that interstitial copper atom concentration increases with temperature and deviation from stoichiometry.
关键词： phase transition,lattice parameters,mechanochemical synthesis,Cu2 – xSe,X-ray diffraction,thermodynamic equilibrium
更新于2025-09-23 15:21:01
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3D auto-context-based locality adaptive multi-modality GANs for PET synthesis
摘要： Positron emission tomography (PET) has been substantially used recently. To minimize the potential health risk caused by the tracer radiation inherent to PET scans, it is of great interest to synthesize the high-quality PET image from the low-dose one to reduce the radiation exposure. In this paper, we propose a 3D auto-context-based locality adaptive multi-modality generative adversarial networks model (LA-GANs) to synthesize the high-quality FDG PET image from the low-dose one with the accompanying MRI images that provide anatomical information. Our work has four contributions. First, different from the traditional methods that treat each image modality as an input channel and apply the same kernel to convolve the whole image, we argue that the contributions of different modalities could vary at different image locations, and therefore a unified kernel for a whole image is not optimal. To address this issue, we propose a locality adaptive strategy for multi-modality fusion. Second, we utilize 1×1×1 kernel to learn this locality adaptive fusion so that the number of additional parameters incurred by our method is kept minimum. Third, the proposed locality adaptive fusion mechanism is learned jointly with the PET image synthesis in a 3D conditional GANs model, which generates high-quality PET images by employing large-sized image patches and hierarchical features. Fourth, we apply the auto-context strategy to our scheme and propose an auto-context LA-GANs model to further refine the quality of synthesized images. Experimental results show that our method outperforms the traditional multi-modality fusion methods used in deep networks, as well as the state-of-the-art PET estimation approaches.
关键词： Image synthesis,Positron emission topography (PET),Locality adaptive fusion,Generative adversarial networks (GANs),Multi-modality
更新于2025-09-23 15:21:01
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[NanoScience and Technology] Silicene (Prediction, Synthesis, Application) || Germanene: Silicene’s Twin Sister
摘要： Soon after the discovery of graphene, the first two-dimensional material, many other two-dimensional materials have been developed. Due to their s2 p2 type of electronic structure the elements of the ‘carbon’ column of the periodic system i.e. silicon, germanium and tin have received a lot of attention as potential two-dimensional materials. The silicon, germanium and tin analogues of graphene are coined silicene, germanene and tinene or stanene, respectively, and share many properties with graphene. There are, however, also a few distinct differences with graphene. Here we will give a brief update on the current status of germanene. We briefly review the various routes to synthesize germanene and elaborate on its structural and electronic properties as well as its potential for application in future electronic devices.
关键词： silicene,two-dimensional materials,electronic properties,synthesis,germanene
更新于2025-09-23 15:21:01
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Ethanol–water-assisted room temperature synthesis of CsPbBr3/SiO2 nanocomposites with high stability in ethanol
摘要： All-inorganic halide perovskites have attracted great attention by virtue of the merits of bright emission, tunable wavelength and narrow-band emission. Despite the excellent optical features, all-inorganic halide perovskite materials have suffered from intrinsic instability, which has limited their applications in various optoelectronic devices. To mitigate the intractable issue, we demonstrated the CsPbBr3 nanoparticles decorated with smaller SiO2 nanocrystals to passivate the surface defects; SiO2 nanoparticles were applied as a barrier layer to maintain the optical property and enhance environmental stability. A facile in situ method was proposed to prepare CsPbBr3/SiO2 nanocomposites, in which an environmental ethanol/water solvent system was needed with the addition of tetraethyl orthosilicate (TEOS) as a silicon precursor. The obtained CsPbBr3/SiO2 nanocomposites have better optical characteristic and stability than bare CsPbBr3 nanoparticles. Even 70% photoluminescence intensity of as-prepared CsPbBr3/SiO2 nanocomposites can be maintained after 168 h storage in ethanol. This newly developed synthesis will open up a new route for the fabrication of optoelectronic devices in an environmentally friendly way, and the as-obtained perovskite materials with improved stability will make them great potential for multifunctional optoelectronic devices.
关键词： Ethanol–water-assisted room temperature synthesis,All-inorganic halide perovskites,High stability,CsPbBr3/SiO2 nanocomposites,Optoelectronic devices
更新于2025-09-23 15:21:01
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The use of Highly Ionized Pulsed Plasmas for the Synthesis of Advanced Thin Films and Nanoparticles
摘要： Pulsed plasma processes open up the possibility of using very high plasma densities and modulated deposition in the synthesis of thin films and nanoparticles. The high plasma densities lead to a high degree of ionization of the source material, which creates new possibilities for surface engineering. Ions can, in contrast to atoms, be easily controlled with regard to their energy and direction, which is beneficial for thin film growth. Furthermore, ions can also increase the trapping probability of material on nanoparticles growing in the gas phase. The pulsed sputter ejection of source material also has other consequences: the material in the plasma and the material arrival on the growth surface will fluctuate strongly resulting in high level of supersaturation during pulse-on time. In this paper, an overview of the generation and properties of highly ionized pulsed plasmas is given. In addition, the use and importance of these types of discharges in the fields of thin-film and nanoparticle growth are also summarized.
关键词： HiPIMS,HPPMS,sputtering,IPVD,thin films,nanoparticle synthesis
更新于2025-09-23 15:21:01
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Synthesis and Spectral Characteristics of BODIPY Dyes with Two or Three Dipyrrin Domains
摘要： Several boron-dipyrrin (BODIPY) based fluorophores with two and three dipyrrin cores were synthesized and investigated in solvents under the concentration variation. Comparative analysis of spectral and photophysical changes under increasing the number of the cores in the dye molecule was made. Mutual influence of dipyrrin cores was detected leading to the increasing of the compounds rigidity and, thus, the absence of fluorescent molecular rotor effects under the viscosity variation. Aggregation induced quenching, which was observed for many mono-domain BODIPY dyes is reduced in case of investigated poly-domain compounds.
关键词： Aggregation induced spectral changes,Intramolecular rotation,Spectral properties,Synthesis,BODIPY
更新于2025-09-23 15:21:01
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Facile, rapid, one-pot synthesis of hydrogenated TiO2 by using an atmospheric-pressure plasma jet submerged in solution
摘要： We report a simple method for the synthesis of hydrogenated TiO2 (H-TiO2) by submerging an atmospheric-pressure plasma jet in a titanium precursor solution. The synthesized H-TiO2 demonstrates improved visible light absorption and electrical conductivity due to a decreased work function and narrowed band gap. Our plasma system has significant benefits compared to previously reported hydrogenation methods. It offers a facile, one-pot synthesis process, rapid synthesis time, and ease of mass production. We expect the plasma system to be a promising technology for the synthesis of H-TiO2, and believe this method has potential for use in new environmental and optoelectronic applications.
关键词： Synthesis,Titanium dioxide,Plasma,Band gap,Hydrogenation
更新于2025-09-23 15:21:01
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Orientation factor and piezoelectric property in textured (K,Na)NbO <sub/>3</sub> system ceramics with minimal templates
摘要： To lower the sintering temperature and decrease the weight ratio of templates required for fabricating textured (K,Na)NbO3 (KNN) system ceramics, the method of preparing platelike NaNbO3 (NN) single-crystal particles for the templates was improved. The NN crystal particles synthesized by the single-step molten salt method using a mixed salt were treated by ultrasonic vibration and subsequently screened. Using these improved templates, we developed the fabrication method for the textured KNN system ceramics by which the weight ratio of the templates required for the orientation control can be reduced to 1/10 of the conventional weight ratio. The effects of decreasing the weight ratio of templates on sintering temperature, orientation factor, and piezoelectric properties were investigated. In addition, the effects of adding Bi2O3 to KNN calcined powder were also studied to suppress abnormal grain growth, which appears in the textured samples fabricated using smaller amounts of the templates.
关键词： reactive template grain growth,molten salt synthesis,Bi2O3 addition,lead-free piezoelectric materials,ultrasonic treatment,textured ceramics
更新于2025-09-23 15:21:01
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Recent progress in laser materials processing and synthesis
摘要： Already today, high-power lasers have become indispensable for many areas of material processing such as welding, cutting, engraving or drilling. Without them, many industrial production processes are no longer possible. In the age of Industry 4.0, the integration of intelligent production systems and advanced information technologies, laser-assisted material processing, and synthesis will become even more important. Thanks to their high throughput, great precision, and efficiency as well as the excellent quality of the processed products laser-based technologies are on the way of becoming one of the most important processing and production routes of the future. By changing laser parameters such as wavelength or pulse durations many different types of materials, including metals, polymers, ceramics, and their composites can be processed. The energy required for processing can be provided in a localized volume with negligible heat transfer to the surrounding components. Due to these unique properties of lasers, new applications of the laser as a material processing tool are continuously made available. New process pathways in additive manufacturing, surface structuring, material deposition or nanoparticle synthesis are among the newer application areas of lasers.
关键词： nanoparticle synthesis,laser materials processing,laser synthesis,additive manufacturing,high-power lasers
更新于2025-09-23 15:19:57
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Designer cell-self-implemented labeling of microvesicles in situ with the intracellular-synthesized quantum dots
摘要： Cell-derived microvesicles (MVs) are secreted from almost all kinds of mammalian cells into the extracellular space, and play crucial roles in intercellular communication and transporting biomolecules between cells. However, there is a great challenge for visualizing and monitoring of MVs’ bio-behaviors due to the limitations of existing labeling methods. Herein, we report the first paradigm of designer cell-self-implemented labeling of MVs secreted from living mammalian MCF-7 cells in situ using the intracellular-synthesized fluorescent quantum dots (QDs) during the formation of MVs. By elaborately coupling intracellular biochemical reactions and metabolism pathways, the MCF-7 cells can be illuminated brightly by intracellular-biosynthesized fluorescent CdSe QDs. Simultaneously, intracellular-synthesized QDs can be in situ encapsulated by the secreted MVs budding from the plasma membrane of the fluorescing cells to label the MVs with an efficiency of up to 89.9%. The whole labeling process skillfully combines designer precise cell-tuned intricate synthesis of CdSe QDs with mild in-situ labeling via cell-self-implementation just after feeding the cell with suitable chemicals, which is structure- or function-nondestructive and much more straightforward and milder than those by chemical conjugation or indirect encapsulation with conventional fluorogenic labels.
关键词： quantum dot,cell-derived microvesicles,live cell synthesis,cell-self-implementation,in situ labeling
更新于2025-09-23 15:19:57