Dynamical Billiard and a long-time behavior of the Boltzmann equation in general 3D toroidal domains

Establishing global well-posedness and convergence toward equilibrium of the Boltzmann equation with specular reflection boundary condition has been one of the central questions in the subject of kinetic theory. Despite recent significant progress in this question when domains are strictly convex, as shown by Guo and Kim-Lee, the same question without the strict convexity of domains is still totally open in 3D. The major difficulty arises when a billiard map has an infinite number of bounces in a finite time interval or when the map fails to be Lipschitz continuous, both of which happen generically when the domain is non-convex. In this paper, we develop a new method to control a billiard map on a surface of revolution generated by revolving any planar analytic convex closed curve (e.g., typical shape of tokamak reactors' chamber). In particular, we classify and measure the size (to be small) of a pullback set (along the billiard trajectory) of the infinite-bouncing and singular-bouncing cases. As a consequence, we solve the open question affirmatively in such domains. To the best of our knowledge, this work is the first construction of global solutions to the hard-sphere Boltzmann equation in generic non-convex 3-dimensional domains.Comment: 97 pages, 11 figure

Als wär’ es ein Stuck von uns . . . German Politics and Society Traverses Twenty Years of United Germany

This essay looks at postunification Germany through the pages of German Politics and Society. The articles published during this period reveal the evolution of intellectuals' understanding of the unified country—concerns that mirrored changes in social, political, and cultural reality. Of course, academics are beholden to their own histories and Weltanschauung, a fact that produced, at times, prescient, sometimes fragmentary, and sometimes alarmist interpretations and analyses of the country in an attempt to provide orientation. Nevertheless, this review shows how German watchers have slowly up-dated their paradigms and are now not worrying as much about a mellowed, less German country that has fascinated them over the decades.Histor

Predicting Disparity between ASF-Managed Areas and Wild Boar Habitats: A Case of South Korea

African swine fever (ASF) is a highly contagious viral disease affecting both domestic and wild boars. Since its first outbreak in South Korea in 2019, substantial efforts have been made to prevent ASF transmission by reducing the wild boar population and eliminating infected carcasses; however, the persistence of ASF transmission has posed challenges to these efforts. To improve ASF management strategies, the limitations of current management strategies must be identified by considering disparities between wild boar habitats and ASF-managed areas with environmental and anthropogenic characteristics of wild boars and their management strategies. Here, ensemble species distribution models were used to estimate wild boar habitats and potential ASF-managed areas, with elevation, distance to urban areas, and Normalized Difference Vegetation Index as important variables. Binary maps of wild boar habitats and potential ASF-managed areas were generated using the maxSSS as the threshold criterion. Disparity areas of ASF management were identified by overlying regions evaluated as wild boar habitats with those not classified as ASF-managed areas. Dense forests near urban regions like Chungcheongbuk-do, Gyeongsangbuk-do, and Gyeongsangnam-do were evaluated as disparity areas having high risk of ASF transmission. These findings hold significant potential for refining ASF management strategies and establishing proactive control measures

Simulating Hunting Effects on the Wild Boar Population and African Swine Fever Expansion Using Agent-Based Modeling

African swine fever (ASF) is a viral hemorrhagic fever fatal to animals of the Suidae family. It has spread from Africa to Europe and Asia, causing significant damage to wildlife and domesticated pig production. Since the first confirmed case in South Korea in September 2019, the number of infected wild boars has continued to increase, despite quarantine fences and hunting operations. Hence, new strategies are needed for the effective control of ASF. We developed an agent-based model (ABM) to estimate the ASF expansion area and the efficacy of infection control strategies. In addition, we simulated the agents’ (wild boars) behavior and daily movement range based on their ecological and behavioral characteristics, by applying annual hunting scenarios from past three years (2019.09–2022.08). The results of the simulation based on the annual changes in the number of infected agents and the ASF expansion area showed that the higher the hunting intensity, the smaller the expansion area (24,987 km2 at 0% vs. 3533 km2 at 70%); a hunting intensity exceeding 70% minimally affected the expansion area. A complete removal of agents during the simulation period was shown to be possible. In conclusion, an annual hunting intensity of 70% should be maintained to effectively control ASF

Three Dimensionally-Ordered 2D Mos2 Vertical Layers Integrated On Flexible Substrates With Stretch-Tunable Functionality And Improved Sensing Capability

The intrinsically anisotropic crystallinity of two-dimensional (2D) transition metal dichalcogenide (2D TMD) layers enables a variety of intriguing material properties which strongly depend on the physical orientation of constituent 2D layers. For instance, 2D TMDs with vertically-aligned layers exhibit numerous dangling bonds on their 2D layer edge sites predominantly exposed on the surface, projecting significantly improved physical and/or chemical adsorption capability compared to their horizontally-oriented 2D layer counterparts. Such property advantages can be further promoted as far as the material can be integrated onto unconventional substrates of tailored geometry/functionality, offering vast opportunities for a wide range of applications which demand enhanced surface area/reactivity and mechanical flexibility. Herein, we report a new form of 2D TMDs, i.e., three-dimensionally ordered 2D molybdenum disulfide (2D MoS2) with vertically-aligned layers integrated on elastomeric substrates and explore their tunable multi-functionalities and technological promise. We grew large-scale (\u3e2 cm2) vertically-aligned 2D MoS2 layers using a three-dimensionally patterned silicon dioxide (SiO2) template and directly transferred/integrated them onto flexible polydimethylsiloxane (PDMS) substrates by taking advantage of the distinguishable water-wettability of 2D MoS2vs. SiO2. The excellent structural integrity of the integrated vertical 2D MoS2 layers was confirmed by extensive spectroscopy/microscopy characterization. In addition, the stretch-driven unique tunability of their optical and surface properties was also examined. Moreover, we applied this material for flexible humidity sensing and identified significantly improved (\u3e10 times) sensitivity over conventionally-designed horizontal 2D MoS2 layers, further confirming their high potential for unconventional flexible technologies

Cooperative Conformational Change of a Single Organic Molecule for Ultrafast Rechargeable Batteries

We unveil that the conformational change of a single organic molecule during the redox reaction leads to impressive battery performance for the first time. We propose the model material, a phenoxazin-3-one derivative, as a new redox-active bioinspired single molecule for the Li-ion rechargeable battery. The phenoxazin-3-one cathode delivered a high discharge capacity (298 mAh g(-1)) and fast rate capability (65% capacity retention at 10 C). We elaborate the redox mechanism and reaction pathway of phenoxazin-3-one during Li+-coupled redox reaction. The molecular structure alteration of phenoxazin-3-one during the lithium-coupled electron transfer reaction enables strong pi-pi interaction between 2Li-phenoxazin-3-one and carbon, which was evidenced by operando Raman spectroscopy and density functional theory calculation. Our work provides in-depth understanding about the conformational molecular switch of the single molecule during Li+-coupled redox reaction and insight into the design of a new class of organic electrode materials.N

Biological Nicotinamide Cofactor as a Redox-Active Motif for Reversible Electrochemical Energy Storage

Nicotinamide adenine dinucleotide (NAD(+)) is one of the most well-known redox cofactors carrying electrons. Now, it is reported that the intrinsically charged NAD(+) motif can serve as an active electrode in electrochemical lithium cells. By anchoring the NAD(+) motif by the anion incorporation, redox activity of the NAD(+) is successfully implemented in conventional batteries, exhibiting the average voltage of 2.3 V. The operating voltage and capacity are tunable by altering the anchoring anion species without modifying the redox center itself. This work not only demonstrates the redox capability of NAD(+), but also suggests that anchoring the charged molecules with anion incorporation is a viable new approach to exploit various charged biological cofactors in rechargeable battery systems.

Molecular-Linked Z-Scheme Heterojunction of Ti3+-Doped TiO2 and WO3 Nanoparticles for Photocatalytic Removal of Acetaldehyde

Photocatalytic removal of indoor organic air pollutantsis effective,but there are practical limits to catalytic activation by indoor conditions.Here, we report a molecular-linked heterojunction of semiconductingmetal oxide nanoparticles (e.g., Blue TiO2 and WO3) that can be activated by wide-range light including an indoor light-emittingdiode (LED) under ambient conditions. Chemically reduced Blue TiO2 improves visible light absorption of white TiO2 by regulating the electronic structure with self-doping of Ti3+. The heterojunction between Blue TiO2 and WO3 is formed via a molecular linker, and a hybridized electronicstructure of a molecular-linked Z-scheme alignment is generated withoutchanges in chemical characteristics, increasing utilization of indoorlight and effectively improving electron-hole separation. WO3 sufficiently adapts to the photooxidative degradation ofair pollutants by (OH)-O-& BULL;, while Blue TiO2 leads to the effective generation of O-& BULL;(2) (-), leading to the complete decomposition of gaseousacetaldehyde (CH3CHO) to CO2 and CO withoutremaining organic byproducts (e.g., formaldehyde). As a robust interfacialcontact, molecular-linked heterojunctions provide efficient chargeseparation and highly stable performance and enhance solution-processablehomogeneous coatings of metal oxide photocatalysts on real surfaces. Copyright © 2023 American Chemical Society11Nsciescopu