分类： 物理学 >> 凝聚态:结构、力学和热性能 提交时间： 2017-03-26
Xinqiang Wang
Shitao Liu
Dingyu Ma
Xiantong Zheng
Guang Chen
Fujun Xu
Ning Tang
Bo Shen
Peng Zhang
Xingzhong Cao
Baoyi Wang
Sen Huang
Kevin J. Chen
Shengqiang Zhou
AkihikoYoshikawa
摘要： Iron(Fe)-doped InN (InN:Fe) layers have been grown by molecular beam epitaxy. Unlike Fe in GaN, the Fe is found to be donor-like in InN. However, the Fe-concentrations ([Fe]) can’t fully explain the drastic increase of residual electron concentration. Further analysis shows that more unintentionally doped impurities such as hydrogen and oxygen are incorporated with increasing [Fe] and the sample surface is degraded with a large number of pits, which probably are the main reasons for electron generation and mobility reduction. Photoluminescence of InN is also gradually quenched by Fe-doping. This work shows that Fe-doping is one of good choices to control electron density in InN
分类： 天文学 >> 天文学 提交时间： 2025-02-25 合作期刊: 《Research in Astronomy and Astrophysics》
摘要： The dust-scattered stray light in an inner-occulted coronagraph mainly arises from dust particles on the surfaces of the objective lens. Due to the random accumulation of dust on the lens surfaces, it is challenging to monitor this type of stray light and no application can be used for its real-time monitor in the past. In this study, we provide a system and method to overcome this issue, and these have been applied to the Spectral Imaging CoronaGraph (SICG) of the Chinese Meridian Project. The method is based on the relation between the sizes of dust particles and its stray light level at the imaging plane established in the laboratory and the relation between the real size of dust particles and the occupancies on the imaging plane. To monitor the stray light levels accounted for by dusts, one needs only an image of the objective lens that can be provided by the auxiliary imaging system that specially comes with SICG. Our tests show that the errors of the method are less or about 2%, giving a strong confidence in its accuracy. It provides a handy tool to monitor the dust level of the objective lens of SICG and has significantly improved the efficiency of the pipeline of stray light control.
分类： 天文学 >> 天文学 提交时间： 2025-06-13 合作期刊: 《Research in Astronomy and Astrophysics》
摘要： The Spectral Imaging CoronaGraph (SICG) serves as the optical observation equipment of E-corona in the Chinese Meridian Project Phase II, which aims at monitoring the initial source of solar activities. For the purpose of in-depth exploration and space weather forecast in the full chain of Sun–Earth space, SICG is designed to work at two wavelengths of 637.4 and 530.3 nm in the quasi-simultaneous observation mode. Thus, the photometric calibration is more challenging to guarantee accurate scientific data of SICG. Two solar photometers are specially developed to match the observing wavelengths and make the photoelectronic conversion traceable. Correspondingly, the calibration process selects the solar disk center as the brightness reference, which compensates for the photometric losses along the atmospheric transmission path. This study derives the calibration coefficients from the two photometers for the E-coronal brightness processing in real time. By modeling aerosol absorption and scattering and comparing with continuous flat-field observation, the photometric calibration of SICG is evaluated with deviations of 2.1% and 2.3% at 637.4 nm and 530.3 nm, respectively. Based on this, the evolution speed of a multi-temperature coronal loop was analyzed, facilitating further research into the physical mechanisms of coronal mass ejections.
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