岩层倾斜对体应变受气压影响研究

台站实测资料反映地表倾斜时,体应变气压干扰系数明显变大.通过理论计算,求出了地表倾斜度与体应变气压系数的关系,去除气压干扰后,体应变观测的固体潮汐明显改善.     

Effect of reclamation time and land use on soil properties in Changjiang River Estuary,China

The objective of this study is to analyze soil physical and chemical properties,soil comprehensive functions and impact factors after different years of reclamation.Based on the survey data taken from 216 soil sampling points in the Fengxian Reclamation Area of the Changjiang (Yangtze) River Estuary,China in April 2009 and remotely sensed TM data in 2006,while by virtue of multivariate analysis of variance (MANOVA),geo-statistical analysis (GA),prin-cipal component analysis (PCA) and canonical correspondence analysis (CCA),it was concluded that:1) With the in-crease in reclamation time,soil moisture,soil salinity,soil electric conductivity and soil particle size tended to decline,yet soil organic matter tended to increase.Soil available phosphorous tended to increase in the early reclamation period,yet it tended to decline after about 49 years of reclamation.Soil nitrate nitrogen,soil ammonia nitrogen and pH changed slightly in different reclamation years.Soil physical and chemical properties reached a steady state after about 30 years of reclamation.2) According to the results of PCA analysis,the weighted value (0.97 in total) that represents soil nutrient factors (soil nitrate nitrogen,soil organic matter,soil available phosphorous,soil ammonia nitrogen,pH and soil particle size) were higher than the weighted value (0.48 in total) of soil limiting factors (soil salinity,soil elec-tric conductivity and soil moisture).The higher the F value is,the better the soil quality is.3) Different land use types play different roles in the soil function maturity process,with farmlands providing the best contribution.4) Soil physi-cal and chemical properties in the reclamation area were mainly influenced by reclamation time,and then by land use types.The correlation (0.1905) of the composite index of soil function (F) with reclamation time was greater than that with land use types (-0.1161).     

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钻孔应变仪体应力灵敏系数的影响因素研究

分别计算了水泥弹性模量、水泥层厚度、钢筒厚度、岩石弹性模量等对钻孔应变仪体应力灵敏系数的影响,得出:1)在水泥弹性模量小于某个固定值时,体应力灵敏系数随水泥弹性模量的增大而增大,大于这个值时,体应力灵敏系数又随水泥的弹性模量增大而变小;2)当水泥层厚度比N<2时,体应力灵敏系数变化剧烈,受水泥层厚度影响较大;3)体应力灵敏系数随钢筒厚度及岩石弹性模量的增大而变小。     

Python脚本在湖南省第三次国土调查数据库自检中的应用

第三次国土调查数据库是第三次国土调查工作的主要成果,是支撑未来自然资源管理各项工作的关键,其质量必须得到充分重视.对数据库进行充分自检并依据自检问题逐一修改,是减少后期工作量、保障第三次国土调查数据库质量的重要手段.本文通过对湖南省第三次国土调查数据库自检内容和方法的分析,梳理了第三次国土调查数据库自检工作存在的不足,...     

Observations of the inner F and K coronas below λ2220

The inner coronal continuum has been observed and measured below 2220 on the slitless spectra obtained by Speer et al. (1970) at the 7 March 1970 eclipse. These observations set some constraints on the brightness of the inner F corona and hence on the scattering efficiency of the inner interplanetary dust cloud particles in the far ultraviolet. They neither confirm nor reject the possibility that the inner dust cloud has the same sharp upturn in scattering efficiency below 2000 observed in the zodiacal light and in the interstellar medium.On leave from Imperial College, London.This work was supported in part by NASA grant NGL 12-001-011. An I.A.U. travelgrant to one of us (R.J.S.) is gratefully acknowledged.     

Type III Bursts Associated with Millisecond Spikes Which Occurred Within the Frequency Range from 230 to 300 MHz

The metric spectral data obtained at the Yunnan Observatory from July 1990 to December 1991 are analysed and some type III bursts associated with millisecond spikes are found. Their different morphologies reveal the relation between the type III bursts and the millisecond spikes. Based on the occurrence time and the characteristics of continuity and changes of the morphologies in the spikes and the type III bursts of two typical events, we verify that the acceleration region of the coronal electrons is located above the emitting region of the millisecond spikes and the type III bursts. The observations show that the interface frequency of a pair of type III bursts lies near 250 MHz. Finally the authors attempt to explain qualitatively the generating mechanism of the metric millisecond spike-type III bursts by means of the plasma hypothesis.     

Catastrophe of Coronal Magnetic Flux Ropes Caused by Photospheric Motions

Using a 2.5-D, time-dependent ideal MHD model in Cartesian coordinates, we carried out numerical simulations to investigate the equilibrium and evolution properties of a magnetic configuration that consists of a coronal magnetic flux rope and a partly open photospheric background field, which is equivalent to that produced by a two-patch magnetic source on the photospheric surface. The axial and annular magnetic fluxes of the flux rope are given and fixed. The global magnetic configuration evolves in response to three types of changes of the background field: decreasing of the distance between the two sources, shrinking of the size of each source, and increasing of the shear in the closed component of the background field. As a result, the geometrical parameters of the flux rope, i.e. the height of the rope axis, the half-width of the rope and the length of the vertical current sheet below the rope, change due to the variation of the background field. It is shown that for a given coronal magnetic flux rope in a partly open background field, the variation of the geometrical parameters of the flux rope displays a catastrophic behavior, namely, there exists a critical point for each case, at which an infinitesimal change of the background field leads to a loss of equilibrium, and thus a jump of the flux rope. The implication of such a catastrophe in solar active phenomena is briefly discussed.     

The evolution of the z distribution of normal neutron stars in the Galaxy

Under the two initial 1‐D one parameter velocity distribution forms (one is normal, the other is exponential), the z direction scale height evolution of normal neutron stars in the Galaxy is studied by numerical simulation. We do statistics for the cases at different time segments, also do statistics for the cumulative cases made of each time segment. The results show in the cumulative cases the evolution curves of the scale heights are smoother than in the each time segment, i.e., the cumulation improve the signal‐to‐noise ratio. Certainly the evolution cases are different at different Galactic disk locations, which also have very large difference from the average cases in the whole disk. In the initial stages of z evolution of normal neutron stars, after the beginning transient states, the cumulative scale heights increase linearly with time, and the cumulative scale height increasing rates have linear relationship with the initial velocity distribution parameters, which have larger fluctuation in the vicinity of the Sun than in the whole disk. We utilize the linear relationship of the cumulative scale height increasing rates vs. the initial velocity distribution parameters in the vicinity of the Sun to make comparison with the observation near the Sun. The results show if there is no magnetic decay, then the deserved initial velocity parameters are obvious lower than the present well known results from some authors; whereas if introducing magnetic decay, for the 1‐D normal case we can make consistence among concerning results using magnetic decay time values which are supported by some authors, while for the 1‐D exponential case the results show the lackness of young pulsar samples in the larger z in the vicinity of the Sun (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Developing an Advanced Automated Method for Solar Filament Recognition and Its Scientific Application to a Solar Cycle of MLSO Hα Data

We developed a method to automatically detect and trace solar filaments in Hα full-disk images. The program is able not only to recognize filaments and determine their properties, such as the position, the area, the spine, and other relevant parameters, but also to trace the daily evolution of the filaments. The program consists of three steps: First, preprocessing is applied to correct the original images; second, the Canny edge-detection method is used to detect filaments; third, filament properties are recognized through morphological operators. To test the algorithm, we successfully applied it to observations from the Mauna Loa Solar Observatory (MLSO). We analyzed Hα images obtained by the MLSO from 1998 to 2009 and obtained a butterfly diagram of filaments. This shows that the latitudinal migration of solar filaments has three trends in Solar Cycle 23: The drift velocity was fast from 1998 to the solar maximum, after which it became relatively slow. After 2006, the migration became divergent, signifying the solar minimum. About 60 % of the filaments with latitudes higher than 50^° migrate toward the polar regions with relatively high velocities, and the latitudinal migrating speeds in the northern and the southern hemispheres do not differ significantly in Solar Cycle 23.