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关键词： Very low frequency (VLF) signal   Amplitude   Solar flare   Geomagnetic indices  

摘要： The partial solar eclipse on October 25, 2022, had an observable effect on very low frequency (VLF) signals along the transmission paths of GQD (22.10 kHz) and DHO (23.40 kHz). Signal variations were analyzed for October 22-28, 2022, with a focus on amplitude changes during the greatest eclipse (GE) phase. During the partial solar eclipse, the GQD and DHO signal paths experienced 11% and 14% obstructions, respectively. On the day of the eclipse, the amplitude of the GQD is 0.83 dB lower compared to pre-days and 0.11 dB greater than post-days, and for DHO it is increased by 0.26 dB and 0.57 dB for pre- and post-eclipse days at the time of GE. Observations revealed stronger solar flare signatures in GQD signal compared to the DHO signal, attributed to differences in ionospheric conditions along the propagation paths. A pronounced rise in amplitude before and after the GE phase was observed in the GQD signal, linked to solar flare activity. Additionally, the analysis confirmed that the PSE was the primary driver of increased VLF signal amplitude during the GE phase along the DHO path. The results emphasize the significant impact of partial solar eclipses on ionospheric dynamics and VLF signal propagation.

关键词： American astrophysics   total solar eclipse of 1869   United States Nautical Almanac Office   astronomical spectroscopy   solar physics   nineteenth century astronomy   solar eclipse expeditions  

摘要： In the United States, techniques that would one day be called astrophysical were applied later than elsewhere and comparatively suddenly. Their entry into US main-stream astronomy was motivated by a quasi-stochastic phenomenon: a total eclipse of the Sun visible between the contiguous borders of that country. In reaction to the upcoming event, the US Nautical Almanac Office in particular invested time, workforce, and a great deal of money into the measurements of physical astronomy, especially spectroscopy. This occurred although none of its employees had ever expressed-at least, in writing-expertise or even interest in the subject beforehand. Once adopted, physical astronomy, and the investigations it enabled, moved slowly, but steadily, into the mainstream of American astronomy despite objections from traditionalists. In the twenty-first century, spectroscopy and other physical astronomy techniques are essential tools for all astronomers.

摘要： 美国人对树木处理的独特习俗——将枝丫与树干削平,这一看似平凡之举,实则悄然铺垫了树疤诞生的舞台.松木之上,那些因岁月雕琢而生的树疤在树油的润泽与风雨的洗礼下,渐渐幻化出令人叹为观止的抽象图案.这种美,超脱于具象之外,它挑战了我们对树木乃至自然界的传统认知,揭示了自然界中潜藏的无限艺术创造力.

关键词： 混合式教学   研讨式教学   分级教学   高校信息类课程  

摘要： 在分析国内外高校信息类课程教学、分级教学、混合式教学、研讨式教学及分级混合研讨式教学研究现状基础上,对新工科背景下高校信息类课程分级混合研讨式教学模式理论与实践进行了探索.首先给出了研究过程中的基本思路方法,然后指出了其研究目的及意义,最后总结了高校信息类课程分级混合研讨式教学模式的现实性、可行性、实际性、自主研讨与合作研讨及可评价性等取得的主要成果内容.

摘要： 中国（海南）“自贸港”建设和“健康海南”建设需求，对海南卫生健康职业教育提出了更高更新要求。本文基于海南卫生健康职业学院作为新建，且为海南唯一公办高职卫生健康类职业院校，面对新时期职教改革和行业社会服务重任，立足新时期“健康海南”建设人才培养需求，浅析教育链、人才链与产业链、创新链“三链合一”有效衔接在高职卫生健康类人才培养中的意义，为学校推进教育教学改革，深化产教融合，优化专业建设和人才培养，促进“教育性”与“实践性”有机融合，提升专业教育与产业契合度和匹配性，针对性地缓解海南当前存在的卫生健康类高职技术技能型人才供给紧缺与岗位需求之间的矛盾，打造卫生健康类人才培养职教品牌，为助力领跑海南卫生健康职业教育高质量发展，提供理论依据。

关键词： 市域产教联合体   协同创新   人才培养   产业技术创新   地方经济  

摘要： 市域产教联合体的协同创新模式对区域内的教育、产业以及科研资源加以整合,有力促进了教育链、人才链、产业链和创新链的深度交融.例如长治市高端装备制造产教联合体.本次研究剖析了此模式在地方经济、人才培育以及产业技术创新等领域的实际成果.借由产学研的协同协作联合体不但推进了产业结构的优化升级,激发了技术创新活力,还为当地企业持续输送了大批高素质技术人才,提高了就业率带动了经济增长.另外产教融合公共实训基地的构建以及红色教育的融入,进一步增强了人才培养的水平,助推了企业的技术发展,这一模式给区域经济的长久发展提供了强大支撑.

关键词： carrier frequency offset (CFO)   successive convex approximation (SCA)   symbol error rate (SER)   universal filtered multi-carrier (UFMC)   window function  

摘要： In this paper, we first investigate the signal and interference characteristics of the windowed universal filtered multi-carrier (UFMC) system in presence of carrier frequency offset (CFO), and then derive the expression of subcarrier signal-to-interference-plus-noise ratio (SINR). Based on the relationship between symbol error rate (SER) and SINR, an optimization model for window design is formulated to maximize the geometric mean of subcarrier SINR. The successive convex approximation (SCA) algorithm is then employed to solve the optimization problem and determine the optimal window. Finally, SER simulations with various window functions demonstrate that the windowed operations effectively reduce the UFMC interference caused by CFO. Moreover, compared with traditional window functions, the proposed optimal window function significantly improves the system SER, and behaves reliably across a wide signal to noise ratio range. © 2025 Press of Shanghai Scientific and Technical Publishers. All rights reserved.