Far-Field Tunable Nano-focusing Based on Metallic Slits Surrounded with Nonlinear-Variant Widths and Linear-Variant Depths of Circular Dielectric Grating

In this work, we design a new tunable nanofocusing lens by the linear-variant depths and nonlinear-variant widths of circular grating for far field practical applications. The constructively interference of cylindrical surface plasmon launched by the subwavelength metallic structure can form a subdiffraction-limited focus, and the focal length of the this structures can be adjusted if the each groove depth and width of circular grating are arranged in traced profile. According to the numerical calculation, the range of focusing points shift is much more than other plasmonic lens, and the relative phase of emitting light scattered by surface plasmon coupling circular grating can be modulated by the nonlinear-variant width and linear-variant depth. The simulation result indicates that the different relative phase of emitting light lead to variant focal length. We firstly show a unique phenomenon for the linear-variant depths and nonlinear-variant widths of circular grating that the positive change and negative change of the depths and widths of grooves can result in different of variation trend between relative phases and focal lengths. These results paved the road for utilizing the plasmonic lens in high-density optical storage, nanolithography, superresolution optical microscopic imaging, optical trapping, and sensing.Comment: 14pages,9figure

Chemical composition of Y-793605, a martian lherzolite

As a part of consortium study, we have analyzed the Yamato-793605 lherzolitic shergottite by instrumental neutron activation analysis (INAA), radiochemical neutron activation analysis (RNAA) and inductively coupled plasma mass spectrometry (ICP-MS). For comparison, ALH 77005 was also analyzed by INAA and RNAA. Compositionally, Y-793605 is similar to ALH 77005 (and also to LEW 88516). REE abundances for Y-793605 are similar to but slightly lower than those for ALH 77005 and are characterized by a hump around Dy in the CI-normalized pattern. Iridium/Os ratios of Y-793605 and ALH 77005 are exactly chondritic, suggesting that the shergottite parent material had an approximately chondritic Ir/Os ratio. On the other hand, Ni/Co ratios of these two lherzolitic shergottites are lower than the CI value, with both elements being more abundant than refractory siderophiles such as Os and Ir. Presumably, both elements partly existed as oxides when the core formation occurred, but Ni was partitioned into the core more effectively than Co because of the higher stability of the Co oxide. Molybdenum and W are also largely fractionated in Y-793605 and ALH 77005,with Mo being more depleted than W. Apparently, segregation of W into the core was inefficient whereas Mo was more effectively incorporated into the metal-sulfide core. These observations suggest that the oxygen fugacity was considerably elevated when the core formed (at least at the latest stage of core formation)

World heritage - shaping the future

Die Welterbekonvention der UNESCO misst der Vermittlung des gemeinsamen Erbes der Menschheit eine ebenso große Bedeutung bei wie dem Schutz und der Erhaltung der weltweit 1.154 Welterbestätten, von denen sich 51 in Deutschland befinden. Vorliegende Broschüre fasst die Ergebnisse der digitalen Tagung „Welterbe – Auftrag Zukunft gestalten!“ vom 27. und 28. April 2021 zusammen, bei der mit jungen Menschen diskutiert wurde, wie das Welterbe zeitgemäß interpretiert werden kann. Die zahlreichen Beispiele in der Broschüre (darunter auch Sachsens jüngste Welterbestätte, die Montanregion Erzgebirge/Krušnohoří) zeigen, welchen wesentlichen Beitrag das Welterbe zu einer nachhaltigen Entwicklung von Regionen leisten kann und welche wichtige Rolle junge Menschen dabei spielen. Redaktionsschluss: 04.11.202

Characterization of behaviour and hazards of fire and deflagration for high-energy Li-ion cells by over-heating

Fire and deflagration are extreme manifestation of thermal runaway (TR) of Li-ion cells, and they are characterized for fully charged LiNiCoAlO2 (LNCA) 18650 cells in this investigation. The cells are over-heated using a cone calorimeter under different incident heat fluxes. When the cells are exposed to the incident heat flux larger than 35 kW m−2, both fire and deflagration present. The pressure valve opens when the temperature of the cell is higher than 132 °C. The fire occurs with the valve opening when the concentration of the venting vapour in the air is higher than the lower flammability limit. The deflagration happens after the cell temperature arrives about 200 °C, and is mainly arising from the cathode decomposition, the combustion of solvents and the anode relevant thermal reactions. The extreme temperatures of the cell and the flame during deflagration are over than 820 and 1035 °C, respectively. The production of COx, mass loss, heat release rate (HRR) are quantitative identified, and are found increase as the increasing incident heat flux. Based on revised oxygen consumption method, the HRR and liberated heat during the fire and deflagration for the cells are up to 11.8 ± 0.05 kW and 163.1 ± 1.5 kJ, respectively

Investigation on thermal management performance of PCM-fin structure for Li-ion battery module in high-temperature environment

The safety, performance and durability of the Li-ion battery module are limited by the operating temperature especially in the hot temperature regions, hence the thermal management system is essential for battery module. In this paper a novel phase change material (PCM) and fin structure was proposed for the thermal management system of LiFePO4 battery module to reduce the maximum temperature and improve the temperature uniformity in high-temperature environment (40 °C). Carefully designed experiments were performed for model validation. The effects of PCM species, fin thickness, fin spacing and PCM thickness on the cooling performance of battery module were investigated numerically. The results showed that PCM-fin structure thermal management system with optimized design exhibited good thermal performance, keeping the maximum temperature of the battery surface under 51 °C at relatively high discharge rate of 3C. Moreover, by investigating the thermal behavior of PCM during discharge process and cycle test, it has been found that PCM-fin structure has the advantage of improving natural convection and heat conduction within the PCM structure, and as a result enhances heat dissipation efficiency and reduces failure risk in passive thermal management systems using PCMs