Search

Fluidization bed reactor is an attractive method to synthesize and process quantities of functional nanoparticles, due to the large gas–solid contact area and its potential scalability. Nanoparticles fluidize not individually but as a form of porous agglomerates with a typical porosity above 90%. The porous structure has a significant effect on the hydrodynamic behavior of a single nanoparticle agglomerate, but its influence on the flow behavior of nanoparticle agglomerates in a fluidized bed is currently unclear. In the present study, a drag model was developed to consider the porous structure effects of nanoparticle agglomerates by incorporating porous-structure-based drag laws in the Eulerian–Eulerian two-fluid model. Numerical simulations were performed from particulate to bubbling fluidization state to evaluate the applicability of porous-structure-based drag laws. Results obtained for the minimum fluidization and bubbling velocities, bed expansion ratio, and agglomerate dispersion coefficient show that, compared with the drag law of solid sphere, the porous-structure-based drag laws, especially the drag law of fractal porous spheres, provide a closer fit to the experimental data. This indicates that the pore structures have a great impact on gas–solid flow behavior of nanoparticle agglomerates, and the porous-structure-based drag laws are more suitable for describing flows in nanoparticle agglomerate fluidized beds. [ABSTRACT FROM AUTHOR]

Recently, studies on low-dimensional conducting domain walls (DWs) in insulating ferroelectrics have opened up new research areas that allow information to be mechanically written and electrically read on the nanoscale. Large strains in thin films can change the polarization gradient across the DW region and thus increasing the DW current significantly. This phenomenon can enable the development of high sensitivity mechanical vibration sensors. In this study, the effects of variable uniaxial strain on the structures of 180° conducting DWs in LiNbO 3 (LNO) single-crystal thin films bonded onto Si/SiO 2 substrates were investigated. After the creation of antiparallel domains within each LNO nanosensor integrated at the film surface, strain modulation of DW currents was observed through simple mechanical bending of the film. The DW current increases under application of tensile strain along the axis of polarization, but decreases under application of in-plane compression by a factor of approximately 25. Phase field simulations showed the dramatic change in polarization gradients around the DW regions under the increase in tensile strain, which reduced the band gap. Repetitive band-gap narrowing/broadening with change in local electric field intensity under vibrating mechanical forces can periodically modulate both the carrier density and the DW conduction in the sensors. This finding not only provides the new fundamental physics to enrich the ferroelectric theory, but also paves the way to the near-future development of bending actuators, piezolighters, and micro-/nano-manipulators, etc. [ABSTRACT FROM AUTHOR]

Chinese traditional ceramic culture and art are an important foundation for the progress of civilization today, and these cultural foundations are closely related to the daily lives of modern people. Traditional ceramics, as a valuable cultural heritage leftover from ancient times, are inseparable from the various daily lives of modern people and have always played an important leading role in modern people's daily life. Ceramic painting is also an important embodiment form of traditional culture, and the integration of the two is very conducive to enriching people's spiritual world. This paper proposes a VRML-oriented method suitable for establishing a virtual ceramic product space model, that is, a method of building a VRML model with 3DS MAX and other three-dimensional modeling tools combined with a VRML visual editor. According to this method, based on the LOD node, the method is given the optimization and integration method of the virtual ceramic display space scene and completed the modeling of the outdoor background and building required by the virtual ceramic product display space scene. Subsequently, the interactivity of the virtual ceramic display space in the web application is explained, the realization method of the color switching and placement of the virtual ceramic product based on the built-in sensor is proposed, and the interaction based on the external data source of the web page is also given. Finally, in this article, the response time of the page can be basically controlled below 4 s/time, and after a long-term stress test, the system can still maintain the stability of operation, and the probability of serious errors is less than 0.512%. [ABSTRACT FROM AUTHOR]

Ferroelectric domain-wall random access memory (DWRAM), based on the utilization of highly conductive domain walls in insulating ferroelectric LiNbO 3 (LNO) single-crystal thin films, holds great promise for the future of memory storage. The ability to scale this technology up in a crossbar architecture means that it has the otential to surpass the storage density capabilities of commercial ferroelectric random access memory devices. Nevertheless, the passivation layer in the vertically integrated structure (VIS) architecture is critical because it affects many vital parameters of the memory such as retention, on/off current ratio, reliability, etc. Therefore, a detailed strain investigation of silicon nitride and silicon dioxide fabricated by plasma-enhanced chemical vapor deposition (PECVD) is presented. Furthermore, the effect of residual strain on the electrical properties of LNO DW cells was investigated. The results indicated that a monolayer of SiO 2 or Si 3 N 4 is not a good choice for the insulating layer because of the undesirable passivation caused by defects and residual strain. Hence, a Si 3 N 4 /SiO 2 composite passivation layer is proposed, which not only solves the residual strain problem but also ensures good insulation performance. Finally, a crossbar array of DW memory cells with an on/off current ratio greater than 104 was fabricated using the Si 3 N 4 /SiO 2 composite dielectric layer, demonstrating good uniformity and retention. This work validates the feasibility of high-density integration of LNO domain wall memories and provides a foundation for selecting passivation layers in the VIS architecture. • In ferroelectric domain wall random access memory, SiO 2 or Si 3 N 4 is not a good choice for insulating layer due to undesirable residual strain. • A Si 3 N 4 /SiO 2 composite passivation layer not only solves the residual strain problem, but also ensures good insulation performance. • A crossbar array of DW memory cells was fabricated using the Si 3 N 4 /SiO 2 composite dielectric layer, demonstrating good uniformity and retention. [ABSTRACT FROM AUTHOR]

In order to solve the problem of shortage of carbon source for biological denitrification in advanced treatment of the effluent from secondary treatment of sewage, five kinds of fruit shells (pistachio shell, peanut shell, ginkgo shell, walnut shell and hazelnut shell) were preliminarily selected from eight kinds of fruit shells for experiments of static carbon release and denitrification. The carbon release performance (amount and law of carbon release and biodegradability of released carbon) and denitrification performance of different shells were investigated. Results showed that the peanut shell had the largest amount of carbon release (0.88 mg chemical oxygen demand [COD] g−1) and the highest removal rate of nitrate (NO 3 −-N) (76.48% ± 4.06%). However, the released carbon could not be fully utilized by denitrifying bacteria, resulting in a (205.90% ± 59.49%) increase in effluent COD compared with influent. The amounts of carbon release of ginkgo nut shell, walnut shell, and hazelnut shell were low (0.45, 0.41, and 0.43 mg COD g−1, respectively). The released carbon could not be used easily by microorganisms. Meanwhile, the contents of degradable aromatic protein and protein-like in dissolved organic matter (DOM) were low. Even the fulvic acid–like with low biodegradability also appeared in the soaking solution of the hazelnut shell. The NO 3 −-N and total nitrogen aveage removal rates were low in these three fruit shells and showed the removals within the 54.10–57.25% range and 52.21%–54.24% range, respectively. The amount of carbon release of pistachio shell was lower than that of peanut shell. However, the released carbon of the former was more biodegradable than that of the latter. Moreover, the relative molecular mass of DOM was small, and the contents of aromatic protein and protein-like were much higher than those of the four other kinds of fruit shells. The NO 3 −-N removal rate (71.48% ± 0.98%) of pistachio shell was only slightly lower than that of peanut shell. In conclusion, pistachio shell was the best carbon source for biological denitrification in the advanced treatment. [Display omitted] • Fruit shells were used as solid carbon sources for biological denitrification. • The performances of different fruit shells as carbon sources were compared. • DOM was used to characterize the quality of carbon sources. • Pistachio shell had the best carbon source quality and wastewater treatment effect. [ABSTRACT FROM AUTHOR]

[Display omitted] • Develop a modularity data-driven scheme with high efficiency and accuracy to quantitatively describe microstructural evolution. • Practical application of the scheme on a simulated eutectic patterns evolution by the phase-field method. • Uncovering the dynamic variation of eutectic patterns under different interface energy and initial lamellar spacing conditions. Solid-liquid interface dynamics plays a crucial role in microstructure evolution during solidification. However, it is difficult to extract sufficient spatial information to describe the variation in the irregular and non-periodic solid-liquid interface domains, resulting in a challenge remaining in quantifying analysis by a quick and low-dimensionally visualized way. We proposed an interface-oriented two-point statistics method to solve the unbiassed statistics of the spatial information in these irregular and non-periodic interfaces. The challenge was successfully overcome by a carefully designed data-driven scheme, which has the advantages of easy to operate, high accuracy and efficiency. Taking the eutectic microstructure evolution simulated by phase-field method as an example, we also obtained novel insights on tailoring eutectic patterns, that is, the transformation of four patterns (lamellar elimination, regular lamellae, oscillatory eutectics and branching lamellae) depends on initial lamella spacing whether the interface energy is isotropic or anisotropic. Additionally, interfacial energy anisotropy, compared to the isotropic case, not only prolongs the time of patterns transformation, but also narrows the spacing range between elimination and creation of lamellae. Our proposed scheme is also able to be applied into more occasions about microstructure evolution in different materials systems. [ABSTRACT FROM AUTHOR]

Processing-structure (PS) linkages play a significant role in materials development. Nevertheless, currently there is a fascinating but of bottleneck task in terms of instantiating microstructure to understand and validate PS linkages. Its challenge lies on the lack of a robust method in computation efficiency and accuracy. Inspired from several advanced techniques such as hybrid input-output (HIO) algorithm, image processing operations and different-phase neighbors-based pixel swapping rule, we proposed a continually reactivating iterative-projection process (CRIP) method to address the challenge above. The output at each iteration in CRIP is continuously improved by eliminating and moving isolated or noise pixels towards an error-reduction direction to activate the iterative-projection process of the next iteration. The performance of the method was examined on two microstructure examples. It shows at least 99.86% improvement in convergence time compared with the classical simulated annealing algorithm and around 6.14 × 10−4 reduction in error compared with the traditional HIO algorithm. More importantly, CRIP is suitable for the task of instantiating microstructure from periodic two-point statistics predicted by PS linkage, which has been demonstrated by applying it to two experimental datasets of Ni-based superalloys and dual-phase steels. Our proposed method has the advantages of high efficiency, easy operation, reliable accuracy and remarkable generalization ability. [Display omitted] [ABSTRACT FROM AUTHOR]

The application of polymer materials in sculpture art creation is extensive and plays a significant role in the development of sculpture art. This article aims to systematically explore the application of polymer materials in contemporary sculpture art creation. The research comprehensively applies various techniques such as literature research, data comparison, and case analysis to explore in detail the ways, methods, and paths of polymer materials employed in the shaping, decoration, and protection of sculptural artworks. First, the article analyzes three methods of shaping sculpture artworks with polymer materials (casting, printing, and constructing). Secondly, it explores two techniques of using polymer materials to adorn sculpture artworks (coloring and imitating texture); then it discusses the significant approach of using polymer materials to protect sculptural artworks (protective spray film). Finally, the research identifies the merits and demerits of using polymer materials in contemporary sculpture art creation. The findings of this study are expected to enrich the effective application of polymer materials in contemporary sculpture art creation and offer novel techniques and ideas for contemporary sculpture art creators. [ABSTRACT FROM AUTHOR]

Ceramicized polymer composites are prepared by adding various additives into the polymer matrix, such as functional clay fillers, porcelain-forming additives, crosslinking agents, flame retardants, reinforcement agents, etc. In recent years, polymer materials have been widely used in the preparation of ceramic materials. Moreover, the addition of polymer materials in ceramic materials results in increased bending in the ceramic body, and its mechanical strength has been greatly improved; this advantage has led many contemporary ceramists to use polymer materials in the creation of ceramic works, providing ceramic creation more space for operation. The introduction of polymer materials into ceramic materials brings more possibilities than traditional ceramic creation based on the tests of toughness, strength, and yield of the ceramic body. This article investigates ceramic raw materials with high-polymer material ceramic function, high-polymer materials for modern pottery to convey the artistic expression of porcelain texture, as well as the use of high-polymer materials in gel-powered three-dimensional (3D) printing to refine the injection molding process, all of which solve the difficulties of creating delicate artworks in modern ceramic art creation. This paper mainly adopts the research method of recording and comparing the numerical value of adding ceramic materials into polymer materials and the physical shape after firing in ceramic creation, to form a relatively stable numerical value and firing curve for a certain type of ceramic creation form. In this regard, the integration of modern ceramic creation and polymer materials makes ceramic works a relatively special style in contemporary art, increasing its cultural connotation and visual tension. [ABSTRACT FROM AUTHOR]

[Display omitted] • A surrogate model for dendritic microstructures in solidification is established. • A rational way to choose the reduced-order features is proposed. • Including more reduced-ordered features may worsen the microstructure prediction. Establishing a rigorous quantitative relationship between solidification parameters and microstructure is critical for facilitating the fabrication of metallic components with desired properties. Conventional approaches are time and effort intensive and lack a rigorous framework for the systematic and accurate quantification of microstructure. In this study, a novel data science approach is applied to extract high-value, computationally low-cost process-structure linkages from phase field simulations of dendritic grain growth during solidification. Reduced-order measures, which are adequate for identifying the salient features of microstructures and evaluating the effects of solidification process parameters, are obtained through two-point statistics and principal component analysis. Building on these reduced-order measures, computationally efficient surrogate models are established using various regression methods. It is demonstrated that the surrogate model with the best predictive performance can provide good predictions of not only the reduced-order measures but also the two-point statistics. Moreover, it is found that some reduced-order measures exhibit very complex relations with process parameters, which results in poor prediction accuracy. Compared with discarding the features with inaccurately predicted values, including them may lead to worse recovery of higher-order microstructure statistics. These results highlight the importance of microstructure feature selection in the improvement of prediction accuracy. [ABSTRACT FROM AUTHOR]

Background: Mosquito-borne diseases threaten human health, but mosquito control faces various challenges, such as resistance to chemical insecticides. Thus, there is an urgent need for more effective and environment-friendly control agents. Capsaicin can downregulate the mTOR signaling pathway of tumor cells. The TOR signaling pathway can mediate the expression of vitellogenin (Vg) to regulate the fecundity of insects. Whether capsaicin has the potential to inhibit fecundity of mosquitoes by regulating TOR pathway and Vg expression is currently unclear. Methods: Anopheles stephensi were fed with blood of mice administered capsaicin by gavage or sugar containing capsaicin followed by a blood feeding with normal mice. Then, the engorged female mosquitoes were tubed individually and underwent oviposition. The eggs and individuals in the subsequent development stages, including larvae, pupae, and emerging adults, were counted and compared between the capsaicin treatment and control groups. Additionally, total RNA and protein were extracted from the engorged mosquitoes at 24 h post blood feeding. Real-time PCR and western blot were performed to detect the transcriptional level and protein expression of the key fecundity-related molecules of mosquitoes. Finally, TOR signaling pathway was inhibited via rapamycin treatment, and changes in fecundity and the key molecule transcription and protein expression levels were examined to verify the role of TOR signaling pathway in the effect of capsaicin on mosquito fecundity. Results: The laid and total eggs (laid eggs plus retained eggs) of An. stephensi were significantly reduced by feeding on the blood of capsaicin-treated mice (P < 0.01) or capsaicin-containing sugar (P < 0.01) compared with those in the control group. Moreover, the transcription and protein expression or phosphorylation levels of fecundity-related molecules, such as Akt, TOR, S6K, and Vg, were significantly decreased by capsaicin treatment. However, the effects disappeared between control group and CAP group after the TOR signaling pathway was inhibited by rapamycin. Conclusions: Capsaicin can decrease the fecundity of An. stephensi by inhibiting the TOR signaling pathway. These data can help us to not only understand the effect of capsaicin on the reproductive ability of An. stephensi and its underlying mechanism, but also develop new efficient, safe, and pollution-free mosquito vector control agents. [ABSTRACT FROM AUTHOR]

The oxidation behavior of a niobium-bearing high nickel-chromium alloy, widely used in the petrochemical industry, is systematically studied at 800 °C using a combination of transmission electron microscopy and atom-probe tomography experimental techniques and thermodynamic calculations. Oxidation leads to complex surface microstructures consisting of a protective chromia layer, an amorphous SiO 2 (silica) layer, Fe- and Ni-rich metallic mushroom-like austenitic protrusions/precipitates, and sub-oxide voids with highly faceted surfaces. The thermodynamic equilibrium oxides of this alloy are studied as a function of oxygen activity using Thermo-Calc and compared to the observed microstructures. The growth kinetics of oxide layers are studied in detail. • Ni-Cr alloy oxidation behavior for protective oxide layer. • Multi-layered oxide characterization using TEM & APT. • Mechanisms of austenitic protrusions in oxide identified. • Examined thermodynamics in carbide stability, oxidation. [ABSTRACT FROM AUTHOR]

• The conductivity of the NDWs is three orders of magnitude higher than the T-T DWs but is one order of magnitude lower than the H-H DWs in a LiNbO 3 transistor. • The wall current is affected by discontinuous domain retraction across different voltage sweeping ranges. • The wall current is thermally activated and the activation energy changes at 260 K. Conducting domain walls in an insulating ferroelectric matrix are interesting for the development of next generation multifunctional nanodevices with large output powers. However, electrical conductions are diversified among head-to-head (H-H), neutral (N), and tail-to-tail (T-T) domain walls (DWs) with disputable conduction mechanisms. It is generally accepted that the charged DWs are more electrically conductive than the neutral DWs. However, the charged walls are unstable due to high depolarization energies. Here, we stabilized the H-H DWs, NDWs and T-T DWs within a LiNbO 3 transistor by controlling charge injection in compensation of the domain boundary charge under applied drain–gate, drain–source and gate–source voltages. The walls were created through the local 180° domain reversals in different inclined angles, and the transistors in different sizes were fabricated at the surfaces of 5 mol.% MgO-doped LiNbO 3 single crystals in monodomain patterns. The NDWs are positively charged due to small inclination angles (~1°) and local sideways meandering behavior of the charged dipoles with electrical conduction that is three orders of magnitude higher than that across the T-T DWs but is one order of magnitude lower than that across the H-H DWs. Voltage dependences of wall currents can be fitted according to the space-charge-limited current equation with an exponential coefficient varying between 2.1 and 3.7 in some specific voltage ranges, implying discontinuous domain retraction in different inclined wall angles against the reduced applied voltage to affect the wall current. This finding provides the fundamental physics to improve domain wall conduction via domain reconstruction and broadens the domain wall application in future nano-devices. [ABSTRACT FROM AUTHOR]

The dissolution behavior of γ/Laves eutectic within a typical Ni-based superalloy (Inconel 718) was investigated by in-situ and conventional transmission electron microscopy (TEM) techniques. The results show that the Laves phase dissolved firstly at 700°C, but a new Ni 7 Nb 2 phase possessing similar composition with δ-Ni 3 Nb phase precipitated near Laves phase did not dissolve at temperatures up to 950°C. The new Ni 7 Nb 2 phase with lattice parameters: a =0.473 nm, b =0.794 nm, c =1.21 nm and β =91.3°, shows a C2/m space group symmetry. The crystal structure of the new Ni 7 Nb 2 phase can be understood by "triple layers" as the Ni 7 Zr 2 -type structure does, stacking perpendicular to the (001) planes. Instead of stacking with one single shift vector s corresponding to the Ni 7 Zr 2 -type structure, the stacking sequences of the new Ni 7 Nb 2 can be characterized by alternate occurrence of + s and - s. Moreover, the structural change of γ/Laves eutectic constituent before and after heat treatment was investigated. The Ni 7 Nb 2 could remain after heat treatment. Since the experimental Ni 7 Nb 2 structure was shown to be unstable in the Ni-Nb binary system by calculation, it is suggested that Zr, Si and Co promote the formation of Ni 7 Nb 2 phase in superalloys according to the segregation behaviors of elements. Moreover, as Ni 7 Zr 2 is considered to be detrimental to the mechanical properties, Ni 7 Nb 2 phase should also have negative influences and should be eliminated through possible approaches. The finding of the new phase should shed light on the microstructural controlling and heat treatment process formulating of superalloys. [Display omitted] [ABSTRACT FROM AUTHOR]

This work proposed a kinetic model for RP-3, the most widely used military-civilian aviation fuel in China. Four hydrocarbons within the typical size of major components in RP-3, i.e., n-dodecane, iso-dodecane (2,2,4,6,6-pentamethylheptane), decalin and n-butylbenzene, were included in the component palette to improve the ability of the surrogate to mimic the properties related to the molecular weight. Seven properties, cetane number, molecular weight, H/C ratio, threshold sooting index, lower heating value, the proportion of -CH 3 and -CH 2 in the total carbons were selected as targets aiming at the comprehensive emulation of the chemical and physical propensities of RP-3. By sequential use of the genetic algorithm and a local search method, a surrogate containing 27.44% n-dodecane, 28.81% iso-dodecane, 26.12% decalin and 17.63% n-butylbenzene by mole was formulated. The autoignition delay times of the surrogate were measured using a heated rapid compression machine at pressures of 10, 15, 20 bar and equivalence ratios of 0.5, 1.0 and 2.0 over low-to-intermediate temperature range. Results show that the surrogate can not only emulate the target properties but also the key non-targeted properties. A kinetic model of 3065 species and 11,898 reactions was then developed based on the proposed surrogate to describe the chemical process during the combustion of RP-3. Simulations show that the model can predict the fundamental combustion datasets in the present work and literature satisfactorily, suggesting the rationality and applicability of the model. Rate of production and evolution histories of OH and HO 2 were then conducted using the kinetic model to provide insight into the combustion of RP-3. Analysis suggests that negative temperature coefficient behavior also exists in the first stage ignition. [ABSTRACT FROM AUTHOR]