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数字温度控制仪表在生产生活中应用广泛,测量方法呈现多样性。该研究应用高精度化整系统和数字二度仪表原理,分析实验设备和测量方式对温度的影响。研究发现重复性测量方法中间隔测量较连续性测量影响更小。 相似文献
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GPS控制测量是一种比较常见的地形测量方法,并且有着广泛的应用,但是用GPS控制测量方法往往也会存在许多的问题,处理不好这些问题将会导致测量结果不准确,本文目的在于分析GPS控制测量的原理,掌握GPS控制测量常见的问题,避免问题的出现。 相似文献
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本文借助物理学中能量守衡及转换规律对雷云放电过程进行了推理与分析,系统的介绍从雷云发展成熟到消亡的整个过程,以及伴随着的能量发展与变化,从而对雷云放电有了直观认识。由于没有在能量方面形成定量分析,所以对于雷云放电认识的深度还需要做进一步的研究。 相似文献
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Chao Xue Jian-Ping Liu Qing Li Jun-Fei Wu Shan-Qing Yang Qi Liu Cheng-Gang Shao Liang-Cheng Tu Zhong-Kun Hu Jun Luo 《国家科学评论(英文版)》2020,7(12):1803
The Newtonian gravitational constant G, which is one of the most important fundamental physical constants in nature, plays a significant role in the fields of theoretical physics, geophysics, astrophysics and astronomy. Although G was the first physical constant to be introduced in the history of science, it is considered to be one of the most difficult to measure accurately so far. Over the past two decades, eleven precision measurements of the gravitational constant have been performed, and the latest recommended value for G published by the Committee on Data for Science and Technology (CODATA) is (6.674 08 ± 0.000 31) × 10−11 m3 kg−1 s−2 with a relative uncertainty of 47 parts per million. This uncertainty is the smallest compared with previous CODATA recommended values of G; however, it remains a relatively large uncertainty among other fundamental physical constants. In this paper we briefly review the history of the G measurement, and introduce eleven values of G adopted in CODATA 2014 after 2000 and our latest two values published in 2018 using two independent methods. 相似文献
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政府在基础技术发展中的角色--以测量标准为例 总被引:1,自引:0,他引:1
基础技术是指那些在技术体系中处于基础地位,为各类科技与经济社会活动提供支持的技术.测量是一种典型的基础技术.分析了基础测量标准、产业共性测量标准和日常测量标准的不同政策特性,以及相应的政府角色.研究表明,政府在基础技术发展中所承担的角色应根据对象的政策特性而具体确定. 相似文献
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公交IC卡收费系统是以非接触式lC卡为储值卡支付手段,以计算机系统为信息处理方法的安全可靠的现代化管理系统,加快公共汽车收费速度,提高运营效率,以方便广大市民,确保用户利益。 相似文献
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Hao Zhu Zhou Li Chenxi Zhao Xingxing Li Jinlong Yang Chong Xiao Yi Xie 《国家科学评论(英文版)》2021,8(2):110-117
Many layered superlattice materials intrinsically possess large Seebeck coefficient and low lattice thermal conductivity, but poor electrical conductivity because of the interlayer transport barrier for charges, which has become a stumbling block for achieving high thermoelectric performance. Herein, taking BiCuSeO superlattice as an example, it is demonstrated that efficient interlayer charge release can increase carrier concentration, thereby activating multiple Fermi pockets through Bi/Cu dual vacancies and Pb codoping. Experimental results reveal that the extrinsic charges, which are introduced by Pb and initially trapped in the charge-reservoir [Bi2O2]2+ sublayers, are effectively released into [Cu2Se2]2− sublayers via the channels bridged by Bi/Cu dual vacancies. This efficient interlayer charge release endows dual-vacancy- and Pb-codoped BiCuSeO with increased carrier concentration and electrical conductivity. Moreover, with increasing carrier concentration, the Fermi level is pushed down, activating multiple converged valence bands, which helps to maintain a relatively high Seebeck coefficient and yield an enhanced power factor. As a result, a high ZT value of ∼1.4 is achieved at 823 K in codoped Bi0.90Pb0.06Cu0.96SeO, which is superior to that of pristine BiCuSeO and solely doped samples. The present findings provide prospective insights into the exploration of high-performance thermoelectric materials and the underlying transport physics. 相似文献
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目前,我国的高等教育收费制度改革已迫在眉睫。本文正是顺应这个潮流,对我国高等教育收费制度的改革提出了可行性建议。 相似文献
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提出了将软件度量与缺陷管理相结合的设计思想,设计出了一套基于度量的软件缺陷管理系统。该系统通过缺陷管理分析项目的进展、可靠性及开发人员、测试人员的工作状况,使缺陷管理上升到一个量化的阶段,为项目管理者提供了充足、有效的信息。 相似文献
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文章介绍基于 LabVIEW7.0虚拟仪器开发环境下风洞多点压力测量中数据采集的方法.数据采集系统由安装了NI 数据采集卡的计算机和传感器两部分构成,测试界面良好,操作方便,可以实时测量16点动态压力数据,进一步提高了测量效率. 相似文献