Exploring the surface oxidation and environmental instability of 2H-/1T’-MoTe2 using field emission based scanning probe lithography. - In: Advanced materials, ISSN 1521-4095, Bd. 36 (2024), 4, 2310887, S. 1-14
An unconventional approach for the resistless nanopatterning 2H- and 1T’-MoTe2 by means of scanning probe lithography is presented. A Fowler-Nordheim tunneling current of low energetic electrons (E = 30-60 eV) emitted from the tip of an atomic force microscopy (AFM) cantilever is utilized to induce a nanoscale oxidation on a MoTe2 nanosheet surface under ambient conditions. Due to the water solubility of the generated oxide, a direct pattern transfer into the MoTe2 surface can be achieved by a simple immersion of the sample in deionized water. The tip-grown oxide was characterized using Auger electron and Raman spectroscopy, revealing it consists of amorphous MoO3/MoOx as well as TeO2/TeOx. With the presented technology in combination with subsequent AFM imaging it was possible to demonstrate a strong anisotropic sensitivity of 1T’-/(Td)-MoTe2 to aqueous environments. We finally used the discussed approach to structure a nanoribbon field effect transistor out of a few-layer 2H-MoTe2 nanosheet. This article is protected by copyright. All rights reserved
https://doi.org/10.1002/adma.202310887
Influence of the reference surface and AFM tip on the radius and roundness measurement of micro spheres. - In: Measurement science and technology, ISSN 1361-6501, Bd. 35 (2024), 2, 025010, S. 1-16
The performance of tactile and optical surface sensors for nano and micro coordinate measuring machines is currently limited by the lack of precisely characterised micro spheres, since established strategies have mainly been developed for spheres in the range of millimetres or above. We have, therefore, recently focused our research efforts towards a novel strategy for the characterisation of spheres in the sub-millimetre range. It is based on a set of atomic force microscope (AFM) surface scans in conjunction with a stitching algorithm. To obtain an uncertainty statement, the uncertainty about the shape of the reference surface needs to be propagated via the shape of the AFM tip to the actual measurement object. However, the sampling process of an AFM is non-linear and the processing of AFM scans requires complex algorithms. We have, therefore, recently begun to model the characterisation of micro spheres through simulations. In this contribution, this model is extended by the influence of the tip and reference surface. The influence of the tip’s shape and reference surface is investigated through virtual and real experiments. The shape of the tip is varied by using tips with mean radii of 200 nm and 2 μm while sampling the same ruby sphere with a mean radius of 150 μm. In general, the simulation results imply that an uncertainty of less then 10 nm is achievable. However, an experimental validation of the model is still pending. The experimental investigations were limited by the lack of a suitable cleaning strategy for micro parts, which demonstrates the need for further investigations in this area. Although the characterisation of a full sphere has already been demonstrated, the investigations in this contribution are limited to equator measurements.
https://doi.org/10.1088/1361-6501/ad03b7
High performance photothermal carbon nanotubes/nanostructured hydrogel for solar electricity production and solar water sterilization. - In: Applied surface science, Bd. 643 (2024), 158680
Solar energy is a promising renewable energy source with the potential to contribute to sustainable development. Efficient photothermal conversion is critical for solar energy acquisition and conversion. Here, carbon nanotubes (CNTs) were gelatinized to obtain the nanostructured CNT/hydrogel, and then highly light-absorbing CNT/n-hydrogels with surface texture were obtained by replicating the micrometer structure from the black silicon (b-Si) surface onto CNT/hydrogels by using a PDMS mold. Through the synergistic effect of both surface texture and nanostructures, it demonstrates high efficiency of solar electricity production and solar sterilization. A small thermoelectric (TE) module with an area of 4 × 4 cm2 is integrated with CNT/n-hydrogel absorber for the investigation of photo-thermoelectric conversion. The output power of the CNT/n-hydrogel TE device is 1.42 W•m−2 under 1 sun. And by connecting four devices in series, it has successfully demonstrated for charging mobile phones under two different solar illuminations. This work provides a cost-effective and easy fabrication method for opening up the hydrogel as a photothermal absorber, which is low-cost, reproducible, high-efficiency solar water sterilization and high photothermal conversion efficiency.
https://doi.org/10.1016/j.apsusc.2023.158680
High-resolution patterning on LTCC by transfer of photolithography-based metallic microstructures. - In: International journal of applied ceramic technology, ISSN 1744-7402, Bd. 21 (2024), 2, S. 1180-1190
The growing applications and constant miniaturization of electronic devices and of low-temperature co-fired ceramics (LTCC) in various fields, such as aviation, telecommunications, automotive, satellite communications, and military, have led to an increase in the demand for LTCC. Such prospects arise due to the continuous scaling down of components and high-density interconnection in electronics packaging. This paper reports a technique for the transfer of high-resolution microstructures from silicon substrates to LTCC. In this method, gold and copper patterns were formed by photolithography, electrodeposition, and residual layer stripping on silicon substrate. Lithography provides the opportunity to create and transfer complex patterns for use in several different applications and electroplating enables the use of pure metal for excellent electrical properties. The developed structures were transferred onto a top layer of LTCC tape using hot embossing. Then, the subsequent layers were stacked, laminated, and sintered. A resolution of 1.5 μm after free sintering and 4.5 μm after pressure-assisted sintering was achieved. This distinctive method can be useful for several applications requiring high-resolution and superior electrical properties.
https://doi.org/10.1111/ijac.14569
Dynamic-controlled principal component analysis for fault detection and automatic recovery. - In: Reliability engineering & system safety, ISSN 1879-0836, Bd. 241 (2024), 109608
To effectively implement the prognostic and health management for industrial processes, a dynamic-controlled principal component analysis (DCPCA) for pattern extraction and deviation diagnosis is proposed under the framework of multivariate statistical modelling, which can accurately detect and automatically rectify the faults. Significantly, the geometric properties of DCPCA are analysed, revealing the spatial structure relationships of different variables and how the data space is partitioned. In addition, the model relationships in DCPCA are explored, including the dynamic characteristics of time-series variables and the algebraic ones of static variables. Based on these results, statistics are derived for monitoring both the dynamic and static relationships of the process, and under the abnormal circumstance, by diagnosing the deviations between the fault pattern and the setpoint, a fault regulator for automatic recovery is designed. The case study of prognostic and health management for an industrial distillation column illustrates the advantages of DCPCA in fully extracting the process dynamics into pattern, as well as fault detection and automatic recovery.
https://doi.org/10.1016/j.ress.2023.109608
Melt flow, heat transfer and solidification in a flexible thin slab continuous casting mold with vertical-combined electromagnetic braking. - In: Journal of iron and steel research, international, ISSN 2210-3988, Bd. 31 (2024), 2, S. 401-415
During continuous casting of steel slabs, the application of electromagnetic braking technology (EMBr) provides an effective tool to influence solidification by controlling the pattern of melt flow in the mold. Thus, the quality of the final product can be improved considerably. A new electromagnetic braking (EMBr) method, named vertical-combined electromagnetic braking (VC-EMBr), is proposed to be applied to a flexible thin slab casting (FTSC) mold. To evaluate the beneficial effects of the VC-EMBr, the melt flow, heat transfer, and solidification processes in the FTSC mold are studied by means of numerical simulations. In detail, a Reynolds-averaged Navier-Stokes turbulence model together with an enthalpy-porosity approach was used. The numerical findings are compared with respective simulations using the traditional Ruler-EMBr. The results demonstrate that the application of the VC-EMBr contributes significantly to preventing relative slab defects. In contrast to the Ruler-EMBr, the additional vertical magnetic poles of the VC-EMBr preferentially suppress the direct impact of jet flow on the narrow face of FSTC mold and considerably diminish the level fluctuation near the meniscus region. For instance, by applying a magnetic flux density of 0.3 T, the maximum amplitude of meniscus deflection reduces by about 80%. Moreover, the braking effect of the VC-EMBr effectively improves the homogeneity of temperature distribution in the upper recirculation region and increases the solidified shell thickness along the casting direction. On this basis, the newly proposed VC-EMBr shows a beneficial effect in preventing relative slab defects for FTSC thin slab continuous casting.
https://doi.org/10.1007/s42243-023-01062-9
Numerical research for the effect of magnetic field on convective transport process of molten salt in Rayleigh-Bénard system. - In: International journal of thermal sciences, ISSN 1778-4166, Bd. 195 (2024), 108605, S. 1-21
The effects of external applied magnetic field on heat and momentum transfer of Rayleigh-Bénard convection in a closed cavity filled with electrically conductive molten salt are investigated by direct numerical simulation. Such arrangements are of strong interest in the context of thermal energy storage systems from renewable resources. To discretize the governing equations, the Chebyshev collocation spectral method is developed. A series of numerical results for 5000 ≤ Ra ≤ 10^6, 5 ≤ Pr ≤ 20 and 0 ≤ Ha ≤ 150 are obtained. First, we conduct two-dimensional numerical simulations to investigate the effect of Pr without and with magnetic field and find that Pr has little influence on heat and momentum transfer. Then, taking Pr as a fixed value of 7 and considering the effects of Ra and Ha, 2D and 3D direct numerical simulations are conducted. From both 2D and 3D numerical results, we conclude that, the heat and momentum transfer are enhanced with Ra at Ha = 0 and the fluid motion is stabilized by magnetic field at Ha 0. More phenomena of heat transfer and fluid flow, together with scaling correlations of Nu ∼ Ra, Nu ∼ Re for Rayleigh-Bénard convection without magnetic field, and, Nu ∼ RaHa and Re ∼ RaHa for Rayleigh-Bénard convection with magnetic field, are revealed under specified ranges of Ra and Ha.
https://doi.org/10.1016/j.ijthermalsci.2023.108605
Voice work optimization in artistic and pedagogical professions - selected issues :
Wybrane problemy optymalizacji pracy głosem w zawodach artystycznych i pedagogicznych. - In: Nowa Audiofonologia, ISSN 2084-946X, Bd. 12 (2023), 1, S. 65-71
W artykule przedstawiono wybrane zagadnienia pracy głosem w aspekcie monitorowania jego stanu. W kontekâscie dotychczasowych (statycznych) metod analizy statusu aparatu mowy i âspiewu przedstawiono znane metody pomiaru biomarkerów fizjologicznych służ&hlink;acych do diagnozowania potencjalnych patologii. Zaprezentowano także metod&hlink;e badania i konstrukcji systemu pomiarowego, który może byâc wykorzystany do bież&hlink;acej oceny stanu narz&hlink;adów mowy i âspiewu, tak by w czasie rzeczywistym możliwe było podj&hlink;ecie adekwatnych działaân, polegaj&hlink;acych zasadniczo na czasowym zaniechaniu wydawania dâzwi&hlink;eków lub ograniczenia ich intensywnoâsci. W materiale wyeksponowano przewag&hlink;e systemu pomiarowo-kontrolnego, stanowi&hlink;acego techniczne wsparcie dla beneficjenta, nad systemem autokontroli – zawodnym przeważnie z przyczyn socjologicznych lub z powodu niedostatecznie czytelnych sygnałów ostrzegawczych, wysyłanych przez nasz organizm.
https://doi.org/10.17431/na/153096
Formation of the inlet flow profile for passive control of a magnetohydrodynamic liquid-metal flow in a channel. - In: High temperature, ISSN 1608-3156, Bd. 61 (2023), 3, S. 417-428
The paper describes an experimental attempt to affect the flow of liquid metal using a relatively small perturbation at an inlet to a long channel. The purpose is to form a flow structure which is stable in a strong magnetic field at high heat loads, enhance heat transfer, and achieve more predictable flow parameters. It is demonstrated that an obstacle in the form of a rod located transverse to the flow and parallel to the applied magnetic field and installed at the inlet can induce perturbations in the form of regular vortices observed along the flow at lengths as great as several tens of channel hydraulic diameters. The experiments confirm that thus generated vortices considerably change the structure of the isothermal MHD flow. In the case of mixed convection, such vortices suppress the development large-scale thermogravitational fluctuations in the flow and enhance heat transfer under certain flow conditions.
https://doi.org/10.1134/S0018151X23030033
Toward photodynamic cancer chemotherapy with C60-Doxorubicin nanocomplexes. - In: Nanomaterials for photodynamics therapy, (2023), S. 489-522
Recent progress in nanotechnology has attracted interest to a biomedical application of the carbon nanoparticle C60 fullerene (C60) due to its unique structure and versatile biological activity. The dual functionality of C60 as a photosensitizer and a drug nanocarrier sets an opportunity to improve the efficiency of chemotherapeutic drugs for cancer cells. Pristine C60 demonstrates time-dependent accumulation with predominant mitochondrial localization in cancer cells. Nanomolar amounts of C60-drug nanocomplexes in 1:1 and 2:1 molar ratios improve the efficiency of cell treatment, complementing it with photodynamic approach. The cooperative enhancement interactions between mechanisms of chemo- and photodynamic therapies contribute to the obtained synergistic effect (namely “1+1>2”). A strong synergy of treatments arising from the combination of C60-mediated drug delivery and C60 photoexcitation indicates that a combination of chemo- and photodynamic treatments with C60-drug nanoformulations could provide a promising synergetic approach for cancer treatment.
https://doi.org/10.1016/B978-0-323-85595-2.00005-0