分类： 工程与技术科学 >> 物理学相关工程与技术 分类： 工程与技术科学 >> 仪器仪表技术 分类： 电子与通信技术 >> 电子技术 分类： 物理学 >> 交叉学科物理及相关领域的科学与技术 提交时间： 2022-12-29
摘要： 散粒噪声是一个研究量子体系的强有力的手段。本文提出一种用于低温扫描隧道显微镜 (CryoSTM)的跨阻放大器(TIA)，可满足散粒噪声测量的需要。在该TIA中，前置放大器(Pre-Amp)由超低噪声低功率低温高电子迁移率晶体管(HEMTs)构成。以1Gohm的高跨阻增益，所设计的TIA的带宽超过300 kHz。在CryoSTM中，这个TIA连同针尖-样品组件和输入信号被称为CryoSTM-TIA。它的带宽仍然超过300kHz，并且它的等效输入噪声电流功率谱密度在100 kHz小于30 (fA)2/Hz。该CryoSTM-TIA能够用于测量扫描隧道电流谱和扫描隧道微分电导谱。本文又特别阐述了如何用该CryoSTM-TIA测量量子体系的扫描隧道噪声电流功率谱和散粒噪声谱。这就使得用低温CryoSTM-TIA通过测量散粒噪声来研究各种量子体系中的新奇量子现象成为可能，例如在局域尺度中的Andreev反射、在单分子磁体中的Kondo效应，等等。特别是把它用于研究与实现拓扑量子计算有关的Majorana零能模的存在性。
分类： 管理学 >> 管理工程 提交时间： 2021-03-03
摘要： Ecological conservation and high-quality development of the Yellow River Basin (abbreviated to YB Conservation and Development) has been determined as another major national strategies of China, and public sense of gain (PSG) has been generally accepted as a macro-criterion of good governance in China New Time. This paper explored to construct the transmission mechanism of the PSG and YB conservation and development, suggested to take the PSG as a better regulation and guidance for the sound development of the Yellow River Basin. Based on the data of Chinese Social Survey in 2019 (CSS2019), this paper tried to exam the PSG on YB Conservation and Development at the beginning of this Chinese major strategy. An evaluation index system including 5 factor dimensions and 25 indices was constructed, and the normal distribution was used to describe the survey data, after that, the dominance matrix method was applied to make decision based on PROMETHEEⅡ. The empirical analysis results indicated that the PSG of the middle and upper reaches of the Yellow River was lower than the overall level of China, while that of Henan and Shandong in the lower Yellow River were both higher than its national average; and the public generally had a higher sense of gain on government public service and social civilization, however, the PSG on individual self-fulfillments of Henan and Shandong and that on economic situations of the middle and upper reaches of the Yellow River were both at a lower level.
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