| 1 | Deriving Temporal and Vertical Distributions of Methane in Xianghe Using Ground-based Fourier Transform Infrared and Gas-analyzer Measurements显示文摘Methane(CH4)is one of the most important greenhouse gases in the atmosphere,making it worthwhile to study its temporal and vertical distributions in source areas,e.g.,North China.For this purpose,a ground-based high-resolution Fourier transform infrared spectrometer(FTIR),the Bruker IFS 125 HR,along with an in-situ instrument,the Picarro G2301,were deployed in Xianghe County(39.8°N,117.0°E),Hebei Province,China.Data have been recorded since June2018.For the FTIR measurements,we used two observation modes to retrieve the mole fraction of CH4:the Total Carbon Column Observing Network(TCCON)method(retrieval algorithm:GGG2014),and the Network for the Detection of Atmospheric Composition Change(NDACC)method(retrieval algorithm:SFIT4).Combining FTIR with in-situ measurements,we found the temporal and vertical distributions of atmospheric CH4 within three vertical layers(near the ground,in the troposphere,and in the stratosphere),and throughout the whole atmosphere.Regarding the diurnal variation of CH4 near the ground,the concentration at night was higher than during the daytime.Regarding the seasonal variation,CH4 was low in spring and high in summer,for all three vertical layers.In addition,there was a peak of CH4 in winter near the ground,both in the troposphere and the whole atmosphere.We found that variation of CH4 in the tropospheric column was close to that of the in-situ measurements near the ground.Furthermore,the variations of CH4 in the stratospheric column could be influenced by vertical motions,since it was higher in summer and lower in winter. | Denghui JI Minqiang ZHOU Pucai WANG Yang YANG Ting WANG Xiaoyu SUN Christian HERMANS Bo YAO Gengchen WANG | 2020 | Advances in Atmospheric Sciences2020，37，6： | 2 |
| 3 | Mechanical Properties of Interface between U-0.75Ti Alloy and TiC显示文摘The microhardness and modulus changes of the interface between U-0.75Ti alloy and TiC before andafter heat treatment were studied by SEM and Nano Indenter II, and the results show that the hardness and modulusof the interface are greatly increased after 820℃, 2 h water quenching and 450℃, 6 h aging. This result probablycomes from much more U2Ti and U6Ni precipitates along the interface. | Yong Zhang Junpin Lin Guoliang Chen Gengchen Sun Guanxing Li (State Key Laboratory for Advanced Metals and Materials, UST Beijing, Beijing 100083, China)(Institute of Mechanics Research, Sinica Academy of Science, Beijing, China)(202 Plane Baotou, C | 1998 | International Journal of Minerals,Metallurgy and Materials1998，12，1： | 0 |
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