Early landslide mapping with slope units division and multi-scale objectbased image analysis——A case study in the Xianshui River basin of Sichuan,China

Previous studies on optical remote sensing mapping of landslides mainly focused on new landslides that have occurred, but little attention was paid to the early landslide due to its high concealment. In SAR technology, a prevalent method to detect early landslides, only can be used to identify the potential hazards of slow deformation. Therefore, it is necessary to explore new method of early landslides mapping by integrating all types of direct and indirect early features, such as cracks on slo...     

Thermal properties of harzburgite and dunite at 0.8–3 GPa and 300–823 K and implications for the thermal evolution of Tibet

Thermal diffusivity(D)and thermal conductivity(κ)of harzburgite and dunite from Luobusha ophiolite were simultaneously measured up to 3 GPa and 823 K using the transient plane-source method in a multi anvil apparatus.The results show that the values of D andκof both samples systematically decrease with increasing temperature and increase with increasing pressure.By combination of the thermal physical data of rocks and minerals and geophysical constraints,we performed numerical simulation on the thermal evolution of Tibet vary over depth,distance and geologic ages.The present results provide new constraints on occurrence of partial melting and its geophysical significance beneath Tibetan crust.     

Multifractal Analysis of Element Distribution in Skarn-type Deposits in the Shizishan Orefield, Tongling Area, Anhui Province, China

A series of element concentrations sampled from four drill cores with a length about 1000 m into different skarn-type deposits were selected from the Shizishan orefield, central Tongling, southeastern part of Anhui Province. Using the multifractal method, the distribution and migration characteristics of the major and trace elements are analyzed. The multifractal spectrum of the major elements is left-skewed, whereas the spectrum of the trace elements is right-skewed, which shows that in the process of skarn formation, the trace elements were enriched only locally, and major elements transported within a much larger range. The correlation coefficients of the multifractal parameters Aa （width of the multifractal spectrum） of the four drill cores are relatively low, but the correlation coefficients of the multifractal parameters R （spectrum symmetry parameter） and Af are relatively higher, indicating that although the non-homogeneous intensity of the distribution of elements is inconsistent, their spatial accumulation patterns are almost the same during the ore-forming process. The statistics of the mnltifractal parameters of various elements in the different locations show that the ore-forming processes and element migration pattern in the Shizishan orefield are consistent, and that the migrations of trace elements and major elements exhibit some differences.     

Detection of a high-confidence quasi-periodic oscillation in radio light curve of the high redshift FSRQ PKS J0805–0111

In this work,we have searched for quasi-periodic oscillations(QPOs)in the 15 GHz light curve of the FSRQ PKS J0805-0111 monitored by the Owens Valley Radio Observatory(OVRO)40 m telescope during the period from 2008 January 9 to 2019 May 9,using the weighted wavelet Z-transform(WWZ)and the Lomb-Scargle Periodogram(LSP)techniques.This is the first time to search for a periodic radio signal in the FSRQ PKS J0805-0111 by these two methods.Both methods consistently reveal a repeating signal with a periodicity of 3.38±0.8 yr(>99.7%confidence level).In order to determine the significance of the periods,the false alarm probability method was applied,and a large number of Monte Carlo simulations were performed.As possible explanations,we discuss a number of scenarios including the thermal instability of thin disks scenario,the spiral jet scenario and the binary supermassive black hole scenario.We expect that the binary black hole scenario,where the QPO is caused by the precession of binary black holes,is the most likely explanation.FSRQ PKS J0805-0111 thus could be a good binary black hole candidate.In the binary black hole scenario,the distance between the primary black hole and the secondary black hole is about 1.71×10¹⁶ cm.     

Decomposition effects of Lanzhou lily(Lilium davidii var. unicolor) flowers on soil physical and chemical properties and microbial community diversity

Timely removal of the flower is a key agricultural measure to ensure the concentrated supply of nutrients for the growth of underground bulbs and to increase the yield of lilies. Removing flowers and returning them to the field is one of the traditional ways of treatment, and field litter is formed at this time. Previous study showed that the decomposition of litter changes the soil properties. In order to study the effects of lily litter decomposition on soil physical and chemical properties an...     

FAST Observations of an Extremely Active Episode of FRB 20201124A. Ⅱ.Energy Distribution

We report the properties of more than 800 bursts detected from the repeating fast radio burst(FRB) source FRB20201124A with the Five-hundred-meter Aperture Spherical radio Telescope(FAST) during an extremely active episode on UTC 2021 September 25–28 in a series of four papers. In this second paper of the series, we study the energy distribution of 881 bursts(defined as significant signals separated by dips down to the noise level) detected in the first four days of our 19 hr observational campa...     

Subhalo Abundance and Satellite Spatial Distribution in Milky Way-Andromeda-like Paired Haloes

We study the subhalo and satellite populations in haloes similar to the Milky Way(MW)-Andromeda paired configuration in the Millennium II and P-Millennium simulations. We find subhaloes are 5%–15% more abundant in paired haloes than their isolated counterparts that have the same halo mass and large-scale environmental density. Paired haloes tend to reside in a more isotropic environment than isolated haloes, the shear tensor of their large-scale tidal field is possibly responsible for this diffe...     

The Preliminary Statistical Analysis of LAMOST DR8 Low Resolution AFGK Stars

We download the Large sky Area Multi-Object fiber Spectroscopic Telescope Data Release 8(LAMOST DR8)low resolution catalog for 6,478,063 AFGK type stars and plot the figures of effective temperature,gravitational acceleration and metal abundance.Some small and medium mass stars are evolved from pre-main sequence or main sequence stage to planetary nebula stage or white dwarf stage by the stellar evolution code MESA.We analyze the observed statistical data and model calculation results,and then o...     

地理国情普查的关键技术及实现策略

主要对影像获取与处理、DEM精细化、自动解译技术应用和质检软件流程实现等地理国情普查关键技术的实现策略进行了论述,重点介绍了DEM精细化作业方法,并对比了几种自动解译软件的效率。研究结果表明,该方法能提高近30%的确工作效率。     

Early Cretaceous Climate Changes Recorded in Magnetic Susceptibility and Color Index Variations of the Lower Liupanshan Group, Central China

This study carried out comprehensive analysis on sedimentology, magnetic susceptibility(χlf) and color data of the continental sediments of the Liupanshan Group in Central China so as to obtain climatic change information during the 129.14–122.98 Ma interval. Based on the results of the ?lf and of the redness(a*), the section can be divided into two segments:(1) 129.14–126.3 Ma, with the lowest ?lf values and strongly variable relatively high values of redness and(2) 126.3–122.98 Ma, with high ?lf values and relatively low redness. Analysis of the lithology and facies as well as the magnetic minerals and their contents points to a detrital origin of the magnetic minerals and this allow us to interpret the relationship between magnetic susceptibility variations and climate changes. Our study shows that the climate was significantly dry and hot during the whole studied interval although the interval between 126.3 Ma and 122.98 was a little bit cooler with increased humidity.