Publikationen an der Fakultät für Mathematik und Naturwissenschaften ab 2019

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Radivoievych, Aleksandar; Kolp, Benjamin; Grebinyk, Sergii; Prylutska, Svitlana; Ritter, Uwe; Zolk, Oliver; Glökler, Jörn Felix; Frohme, Marcus; Grebinyk, Anna
Silent death by sound: C60 fullerene sonodynamic treatment of cancer cells. - In: International journal of molecular sciences, ISSN 1422-0067, Bd. 24 (2023), 2, 1020, S. 1-17

The acoustic pressure waves of ultrasound (US) not only penetrate biological tissues deeper than light, but they also generate light emission, termed sonoluminescence. This promoted the idea of its use as an alternative energy source for photosensitizer excitation. Pristine C60 fullerene (C60), an excellent photosensitizer, was explored in the frame of cancer sonodynamic therapy (SDT). For that purpose, we analyzed C60 effects on human cervix carcinoma HeLa cells in combination with a low-intensity US treatment. The time-dependent accumulation of C60 in HeLa cells reached its maximum at 24 h (800 ± 66 ng/106 cells). Half of extranuclear C60 is localized within mitochondria. The efficiency of the C60 nanostructure’s sonoexcitation with 1 MHz US was tested with cell-based assays. A significant proapoptotic sonotoxic effect of C60 was found for HeLa cells. C60′s ability to induce apoptosis of carcinoma cells after sonoexcitation with US provides a promising novel approach for cancer treatment.
Derkach, Volodymyr; Trunk, Carsten
PT-symmetric couplings of dual pairs. - Ilmenau : Technische Universität Ilmenau, Institut für Mathematik, 2023. - 1 Online-Ressource (24 Seiten). - (Preprint ; M23,03)
Eichfelder, Gabriele; Gerlach, Tobias; Rocktäschel, Stefan
Convexity and continuity of specific set-valued maps and their extremal value functions. - In: Journal of applied and numerical optimization, ISSN 2562-5535, Bd. 5 (2023), 1, S. 71-92

In this paper, we study several classes of set-valued maps, which can be used in set-valued optimization and its applications, and their respective maximum and minimum value functions. The definitions of these maps are based on scalar-valued, vector-valued, and cone-valued maps. Moreover, we consider those extremal value functions which are obtained when optimizing linear functionals over the image sets of the set-valued maps. Such extremal value functions play an important role for instance for derivative concepts for set-valued maps or for algorithmic approaches in set-valued optimization. We formulate conditions under which the set-valued maps and their extremal value functions inherit properties like (Lipschitz-)continuity and convexity.
Zhao, Junping; Wang, Yahui; Qian, Yudan; Jin, Huile; Tang, Xinyue; Huang, Zaimei; Lou, Jiayi; Zhang, Qingcheng; Lei, Yong; Wang, Shun
Hierarchical design of cross-linked NiCo2S4 nanowires bridged NiCo-hydrocarbonate polyhedrons for high-performance asymmetric supercapacitor. - In: Advanced functional materials, ISSN 1616-3028, Bd. 33 (2023), 4, 2210238, S. 1-14

Engineering core-shell materials with rationally designed architectures and components is an effective strategy to fulfill the high-performance requirements of supercapacitors. Herein, hierarchical candied-haws-like NiCo2S4NiCo(HCO3)2 core-shell heterostructure (NiCo2S4@HCs) is designed with NiCo(HCO3)2 polyhedrons being tightly strung by cross-linked NiCo2S4 nanowires. This rational design not only creates more electroactive sites but also suppresses the volume expansion during the charge-discharge processes. Meanwhile, density functional theory calculations ascertain that the formation of NiCo2S4@HCs heterostructure simultaneously facilitates OH− adsorption/desorption and accelerates electron transfer within the electrode, boosting fast and efficient redox reactions. Ex situ X-ray diffraction and Raman measurements reveal that gradual phase transformations from NiCo(HCO3)2 to NiCo(OH)2CO3 and then to highly-active NiCoOOH take place during the cycles. Therefore, NiCo2S4@HCs demonstrates an ultrahigh capacitance of 3178.2 F g−1 at 1 A g−1 and a remarkable rate capability of 2179.3 F g−1 at 30 A g−1. In addition, the asymmetric supercapacitor NiCo2S4@HCs//AC exhibits a high energy density of 69.6 W h kg−1 at the power density of 847 W kg−1 and excellent cycling stability with 90.2% retained capacitance after 10 000 cycles. Therefore, this novel structural design has effectively manipulated the interface charge states and guaranteed the structural integrity of electrode materials to achieve superior electrochemical performances.
Ma, Mengmeng; Liu, Jun; Zhao, Huaping; Yue, Shizhong; Zhong, Li; Huang, Yanbin; Jia, Xiaohao; Liu, Kong; Li, Xiaobao; Wang, Zhijie; Qu, Shengchun; Lei, Yong
Broadened photocatalytic capability to near-infrared for CdS hybrids and positioning hydrogen evolution sites. - In: Applied catalysis, ISSN 0926-3373, Bd. 325 (2023), 122327

Wide-spectrum light harvesting is critical in determining practical photocatalysis water splitting. Hybridization presents a viable strategy to broaden photocatalytic capability, yet the direct conversion of near-infrared (NIR) light remains a matter of great concern. Herein, a state-of-art ternary Au nanorodsMoS2-CdS (AMC) hybrid is designed to address this challenge. AMC achieves a leap-forward apparent quantum yield (AQY) of 1.06% at 700 nm and an AQY of 35.7% at 450 nm, extending the hydrogen evolution reaction (HER) capability of CdS hybrids to the NIR region firstly. It is revealed that the energetic hot electrons supplied by Au nanorods (NRs) are responsible for this extension. Indispensable, MoS2 performs a platform to collect the hot electrons from Au NRs and the photoinduced electrons from CdS. The HER active sites are positioned as MoS2-CdS interfaces both from experimental and theoretical viewpoints. This work opens up a new horizon for the forward of the wide-spectrum photocatalysis design.
Qi, Yaru; Qiu, Wenwen; Trunk, Carsten; Wilson, Mitsuru
Spectral inclusion property for a class of block operator matrices. - Ilmenau : Technische Universität Ilmenau, Institut für Mathematik, 2023. - 1 Online-Ressource (12 Seiten). - (Preprint ; M23,02)

The numerical range and the quadratic numerical range is used to study the spectrum of a class of block operator matrices. We show that the approximate point spectrum is contained in the closure of the quadratic numerical range. In particular, the spectral enclosures yield a spectral gap. It is shown that these spectral bounds are tighter than classical numerical range bounds.
Behrndt, Jussi; Gesztesy, Fritz; Schmitz, Philipp; Trunk, Carsten
Lower bounds for self-adjoint Sturm-Liouville operators. - Ilmenau : Technische Universität Ilmenau, Institut für Mathematik, 2023. - 1 Online-Ressource (11 Seiten). - (Preprint ; M23,01)
Hörsch, Florian;
Globally balancing spanning trees. - In: European journal of combinatorics, Bd. 109 (2023), 103644
Xu, Changfan; Dong, Yulian; Shen, Yonglong; Zhao, Huaping; Li, Liqiang; Shao, Guosheng; Lei, Yong
Fundamental understanding of nonaqueous and hybrid Na-CO2 batteries: challenges and perspectives. - In: Small, ISSN 1613-6829, Bd. 0 (2023), 0, 2206445, S. 1-30

Alkali metal-CO2 batteries, which combine CO2 recycling with energy conversion and storage, are a promising way to address the energy crisis and global warming. Unfortunately, the limited cycle life, poor reversibility, and low energy efficiency of these batteries have hindered their commercialization. Li-CO2 battery systems have been intensively researched in these aspects over the past few years, however, the exploration of Na-CO2 batteries is still in its infancy. To improve the development of Na-CO2 batteries, one must have a full picture of the chemistry and electrochemistry controlling the operation of Na-CO2 batteries and a full understanding of the correlation between cell configurations and functionality therein. Here, recent advances in CO2 chemical and electrochemical mechanisms on nonaqueous Na-CO2 batteries and hybrid Na-CO2 batteries (including O2-involved Na-O2/CO2 batteries) are reviewed in-depth and comprehensively. Following this, the primary issues and challenges in various battery components are identified, and the design strategies for the interfacial structure of Na anodes, electrolyte properties, and cathode materials are explored, along with the correlations between cell configurations, functional materials, and comprehensive performances are established. Finally, the prospects and directions for rationally constructing Na-CO2 battery materials are foreseen.
Philipp, Friedrich;
Relatively bounded perturbations of J-non-negative operators. - In: Complex analysis and operator theory, ISSN 1661-8262, Bd. 17 (2023), 1, 14, insges. 30 S.

We improve known perturbation results for self-adjoint operators in Hilbert spaces and prove spectral enclosures for diagonally dominant J-self-adjoint operator matrices. These are used in the proof of the central result, a perturbation theorem for J-non-negative operators. The results are applied to singular indefinite Sturm-Liouville operators with Lp-potentials. Known bounds on the non-real eigenvalues of such operators are improved.