The surface photometry of NGC 3379

Surface photometry is carried out for the photometric standard galaxy NGC 3379 on the basis of two plates in the blue band taken with the Bejing Schmidt telescope. The results, including luminosity profiles, photometric parameters, integrated luminosity distribution, ellipticity and position angle variation, are presented in various forms of figures and tables. Especially our geometric profiles, i.e., ellipticity and position angle variations reach up to 5, much fainter region than that any previous study did. The accuracy of the present data is checked by comparing them with the surface photometry in the literature. We find the zero-point 0.12 mag brighter than the calibration of de Vaucouleurs and Capaccioli (1979), which agrees with the values 0.10–0.15 mag difference claimed by recent observations. The systematic differences is found to be less than 0.1 mag.     

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ML3.7?????????????????93°?????????????????????С??????????????????????????????????2???????￡????????????????????????????????????????????????????????????????4??2??28??ML3.8?????????λ?????????????????????????????????????????????????????????￡????????????     

渭河盆地的水系与现代构造运动

通过卫星象片解释、实地调查测量和查阅历史文献,本文较全面地研究了渭河盆地的水系及其所反映的现代构造运动特征。水系平面组合形态、渭河河型、水系转折及冲沟错位、河流密度、渭河河床的迁移、历史水涝灾害都一致地反映本区现代构造运动继承了第四纪以来的特点。水系历史演变又表明现代构造运动具有周期性。据水系错位和河流流向的统计分析确定本区现代构造应力场主压应力方向为N50°～60°E。本文最后还讨论了根据水系研究现代构造运动的意义以及应注意的问题。     

3-D BAROCLINIC NUMERICAL SIMULATION OF THE SOUTH CHINA SEA I. UPPER CIRCULATION

A three-dimensional baroclinic shelf sea model was employed to simulate the seasonal characteristics of the South China Sea (SCS) upper circulation. The results showed that: in summer, an anticyclonic eddy, after its formation between the Bashi Channel and Dongsha Islands in the northeastern SCS, moves southwestward until it disperses slowly. There exists a northward western boundary current along the east shore of the Indo-China Peninsula in the western SCS and an anticyclonic gyre in the southern SCS. But at the end of summer and beginning of autumn, a weak local cyclonic eddy forms in the Nansha Trough, then grows slowly and moves westward till it becomes a cyclonic gyre in the southern SCS in autumn. At the beginning of winter, there exists a cyclonic gyre in the northern and southern SCS, and there is a southward western boundary current along the east shore of the Indo-China Peninsula. But at the end of winter, an anticyclonic eddy grows and moves toward the western boundary after forming in the Nansha Trough. The eddy‘s movement induces a new opposite sign eddy on its eastern side, while the strength of the southward western boundary current gets weakened. This phenomenon continues till spring and causes eddies in the southern SCS.     

正确测定望远镜光能集中度的方法

正确测定望远镜光能集中度的方法苏定强（中国科学院南京天文仪器研制中心，南京２１００４２）主题词天文光学－望远镜－光学检验天文望远镜广泛采用的象质判据是光能集中度，即一定比例的光能量集中在多大的圆中。例如，七十年代的优秀望远镜光能集中度的标准是８０％的...     

A simple method using climatic variables to estimate canopy temperature,sensible and latent heat fluxes in a winter wheat field on the North China Plain

Estimation of evapotranspiration from a crop field is of great importance for detecting crop water status and proper irrigation scheduling. The Penman–Monteith equation is widely viewed as the best method to estimate evapotranspiration but it requires canopy resistance, which is very difficult to determine in practice. This paper presents a simple method simplified from the Penman–Monteith equation for estimating canopy temperature (T_c). The proposed method is a biophysically‐sound extended version of that proposed by Todorovic. The estimated canopy temperature is used to calculate sensible heat flux, and then latent heat flux is calculated as the residual of the surface energy balance. An eddy covariance (EC) system and an infrared thermometer (IRT) were installed in an irrigated winter wheat field on the North China Plain in 2004 and 2005, to measure T_c, and sensible and latent heat fluxes were used to test the modified Todorovic model (MTD). The results indicate that the original Todorovic model (TD) severely underestimates T_c and sensible heat flux, and hence severely overestimates the latent heat flux. However, the MTD model has good capability for estimating T_c, and gives acceptable results for latent heat flux at both half‐hourly and daily scales. The MTD model results also agreed well with the evapotranspiration calculated from the measured T_c. Copyright © 2008 John Wiley & Sons, Ltd.     

无砟轨道聚氨酯碎石防水联结层单元模型试验研究

基于无砟轨道基床表层水力损伤病害产生机制,提出一种在基床表层上设置聚氨酯碎石防水联结层的水力损伤控制措施。通过建立级配碎石组(J-0)、透水型聚氨酯碎石组(J-5)及致密型聚氨酯碎石组(J-10)3组试验模型,研究聚氨酯碎石防水联结层的静动力特性、疲劳特性与防水特性。结果表明：静力加卸载作用下,J-10残余应变为2.6×10–6,最大位移约为1.0 mm,与下部基床表层级配碎石层变形适应性良好,耗能效果明显,在列车动力荷载水平作用下,可减小基床表层动变形与动应力幅值,增大动应力扩散范围;在长期动力循环荷载作用下,J-0与J-5在注水后结构层动力响应显著增大,而J-10动力响应在加载次数1～2万次后基本保持稳定;试验过程中J-10能够有效防止水分进入基床表层级配碎石层,而J-0与J-5水分不断下渗,引起级配碎石细颗粒损失。研究成果对整治多雨地区无砟轨道基床表层水力损伤病害具有重要的应用价值。     

2021年9月16日四川泸县MS6.0地震强地面运动特征分析

2021年9月16日4时33分在四川省泸州市泸县发生M_S6.0地震,震中附近的强震动观测台网获取了1 320组三分向加速度记录,对有效记录进行常规处理后计算出地震动相关参数,并利用克里金插值方法得到峰值加速度PGA、峰值速度PGV和拟加速度反应谱的空间分布图。结果显示,极震区与中远场的长轴方向有较大差异,地震动表现出沿断裂走向衰减较慢的特性。通过与常用衰减关系预测值进行对比,分析了PGA和多个周期的拟加速度反应谱随距离的衰减特性,结果显示此次地震的PGA相比衰减关系预测值偏小,拟加速度反应谱相比各经验预测值呈现周期越大衰减变慢的特点,体现出川东南地区特有的衰减规律。最后分析了本次地震获得的最大加速度记录,进一步验证了局部地形和场地对地震动有显著影响。      

Deformation characteristics of a large landslide reactivated by human activity in Wanyuan city,Sichuan Province,China

With the rapid urbanization, an increasing number of landslides have been induced by human activities. In this study, a typical human-induced landslide known as the Maobazi landslide, which was triggered by foundation pit excavation in Sichuan Province, China, was analyzed. An emergency investigation was carried out to detect the basic deformation characteristics, followed by implementations of multiple monitoring schemes and emergency control measures to monitor and control reactivated deposits. The reactivated deposits depicted rapid deformations with a maximum deformation exceeding 140 mm from July to September before the emergency control measures were completed. The reactivated deposits gradually settled and were finally controlled in 2019. The results showed that the 2019 Maobazi landslide was a large; reactivated landslide with a scale reached to 520 Mm³, which could result in catastrophic consequences if it slipped down to nearby residential areas.

     

鄂尔多斯盆地东缘奥陶系马家沟组四段豹斑状云质灰岩特征及成因: 以关家崖剖面为例*

鄂尔多斯盆地东缘中奥陶统马家沟组发育豹斑状云质灰岩,因其分布广泛、成因复杂以及具有重要的油气储集意义而长期受到关注。文中以山西省兴县关家崖剖面马家沟组四段顶部为例,依据宏观、微观岩石学特征,结合碳氧稳定同位素、原位激光剥蚀的微量稀土元素等地球化学分析手段,分析了豹斑状云质灰岩的特征及其成因。研究表明,豹斑状云质灰岩的特征为: (1)常发育于(含颗粒)泥晶灰岩中,且向上白云石化程度增强,云质斑块内常伴有针状或板条状石膏假晶;(2)按产状可大致分为水平、斜交和不规则花斑3种类型,分别对应于向上变浅序列的下部、中部和上部,序列顶部多见近原地角砾化;(3)基质灰岩与云质斑块的δ¹³C、δ¹⁸O值较同期海水略显负偏,顶部不规则云质斑块负偏程度最大;(4)“豹斑”与基质灰岩均具有较低的Mn、Sr、Ba等含量和低Mn/Sr值;(5)“豹斑”的ΣREE含量较基质灰岩略低,且皆表现为轻稀土富集、重稀土亏损的稀土配分模式,δCe微弱负异常,δEu无异常。依据上述结果,推测关家崖剖面马四段豹斑状云质灰岩产状受到生物扰动和高频海平面驱动的早成岩期岩溶耦合控制,序列由下至上耦合改造由弱变强,形成下—中部以岩溶影响较小的水平和斜交虫迹为特征、上部叠合岩溶强改造形成不规则花斑的垂向序列组合;早成岩期的暴露岩溶不仅叠合改造生物潜穴,而且蒸发浓缩的有限重卤水沿叠合优势通道优先交代孔渗条件更好的区域,至埋藏时期白云石化作用进一步加强,从而形成了区内类型多样的豹斑状云质灰岩。研究结果还揭示出沉积期微地貌控制的早成岩期岩溶作用是马四段这类特殊的豹斑状云质灰岩或豹斑状云岩储集层形成的关键,且在很大程度上控制了这类储集层的分布,这一认识可为高频暴露驱动的早成岩期岩溶研究提供新的材料。