AO0235＋164射电波段宽带谱指数周期性变化的研究

收集了AO0235＋164天体射电4．8GHz和14．5GHz波段的光变测量数据,并获得了长期的光变曲线,从光变曲线可以看出其活动是非常剧烈的。利用Jurkevieh方法和自相关函数方法分别对AO0235＋164射电波段宽带谱指数进行周期性分析,并对流量和谱指数进行相关性分析,研究结果表明：（1）AO0235＋164天体射电波段4．8GHz-14．5GHz对应的宽带谱指数,可能存在5．30年的光变周期,与Liu等人用功率谱法在射电波段发现其流量密度可能存在5．59±0．47年的光变周期基本吻合;（2）宽带谱指数与流量密度之间存在相关性。     

利用常熟地震台同场地形变仪记录检测对比地球自由振荡信号

利用常熟地震台同场地观测的洞体应变仪、体应变仪、水管倾斜仪、垂直摆倾斜仪记录数据,采用小波变换与功率谱密度估计方法,检测2011年3月11日日本9.0级大地震激发的地球自由振荡信号,其中检测到47个球型基频振型（₀S₃—₀S₄₉）、15个环型基频振型（₀T₅—0T₂₅）以及部分球型谐频振型,与地球初步参考模型（PREM）理论频率值基本符合,表明检测结果较好。对比结果显示：水管倾斜仪检测球型振荡振型能力最强,垂直摆倾斜仪检测环型振荡振型能力最强;体应变仪可检测到清晰的环型基频振型,且信噪比较高;倾斜仪对自由振荡信号的检测能力优于应变仪。     

基于卷积神经网络的电成像图像空白条带填充方法

全井眼微电阻率成像(Fullbore Formation Micro Imager,FMI)技术广泛应用于强非均质性的碳酸盐岩储层测并精细解释.然而,由于各极板间间隙的影响,FMI无法测量360°全井壁地层电阻率信息,这使得FMI图像出现空白条带,严重影响了图像视觉和测井解释进程.为获取全井壁的电阻率信息,必须有效的填充空白条带.本文在探讨现有的电成像图像空白条带填充方法基础上,提出了一种基于卷积神经网络的电成像图像空白条带填充方法.与常用的Criminisi插值法对比填充效果显示:该方法完全适用于各种特征的电成像图像空白条带填充,延续了所有待填充边缘的暗色条带和亮色背景,填充结果与原始图像的像素值频率占比相关性高达0.9581.Criminisi插值法在复杂区域电成像图像的填充结果连通性较差且存在干扰区域,填充结果与原始图像的像素值频率占比相关性仅为0.5924.本文提出的方法具有处理速度快、干扰区域少、连通性强、相关性高的特点,能够满足电成像空白条带成规模填充的实际应用需求,还可为测量极板间的测量缺失带信息处理提供参考手段.     

Sedimentary records of the late Early Cretaceous compressional setting in the South China block: A case study of the Xingning Basin,Guangdong Province

Recently, some scholars have proposed that the South China Block (SCB) was controlled by a compressive tectonic regime in the middle–late Early Cretaceous, challenging the belief that the SCB was under an extensional setting during the Cretaceous. The Early Cretaceous tectonic setting constraint in the SCB can offer vital insight to clarify the Mesozoic subduction history of the Paleo-Pacific. Therefore, to determine the SCB tectonic regime during the Early Cretaceous, this study investigated sedimentary rocks from the Lower Cretaceous Heshui Formation in the Xingning Basin, a foreland basin located in the southeastern SCB. Provenance analysis was performed using sandstone modal analysis, sandstone geochemical characteristics, and detrital zircon geochronology. Based on the results, we discussed basin sediment sources and the SCB tectonic regime during the Early Cretaceous. The results showed that the maximum Heshui Formation depositional age was 103 Ma ± 1.6 Ma in the Early Cretaceous Albian. Detrital framework modes and geochemical characteristics of sandstone indicated that Heshui Formation's source rocks were granites and sedimentary rocks. The detrital zircon U–Pb ages could be classified into two major and four subordinate age populations. The Wuyi Terrane to the north and southeast coastal regions to the east were the primary potential Heshui Formation source areas. However, the lower and upper sandstones are different in the peak ages, ~437 and ~146 to 104 Ma, respectively, indicating that the major source area shifted from the Wuyi Terrane to the southeastern coastal regions during the late Early Cretaceous. The sandstone modal analysis results indicated that the source area comprised mainly collisional–orogenic material. The SCB was under a compressive tectonic regime during the late Early Cretaceous and this compression action continued until at least 103 Ma ± 1.6 Ma.     

Formation blockage risk analysis of geothermal water reinjection:Rock property analysis,pumping and reinjection tests,and long-term reinjection prediction

The blockage induced by particle migration and deposition is one of the main reasons for the decrease of reinjection capacity in the porous geothermal reservoir with a low and medium temperature.In this paper,a new drilled geothermal well in Xining basin China is taken as an example to investigate the formation blockage risk due to the movable clay and sand particles in pores.The physical properties of the reservoir rocks were analyzed,a series of pumping and reinjection tests were conducted,and the longterm reinjection performance of the well was predicted by numerical simulation based on the test fitting.The results show that the geothermal reservoir rocks are argillaceous and weakly cemented sandstones with a content of movable clay and sand particles up to 0.18–23.42 wt.%.The well presented a high productivity of 935–2186 m3?d-1 at a pressure difference of 0.7–1.62 MPa in the pumping tests associated with a large amount of clay and sand particles produced out,while in the reinjection test,only a low injectivity of 240–480 m3?d-1 was observed at an injection pressure of 0.2–0.6 MPa with the clay and sand particles near the wellbore move into deep.According to the prediction,under conditions of a blockage risk,the injectivity of the well will start to decline after 100 days of injection,and in the third year,it will decrease by 59.00%–77.09%.The influence of invasion of pretreated suspended particles and scale particles can be neglected.Under conditions of a high blockage risk,the injectivity of the well will decrease significantly in the first 20–30 days,with a decline of 75.39%–78.96%.Generally,the higher the injection pressure or rate,the greater the decrease in injectivity of the well caused by particle blockage.Pump lifting is an effective measure to remove the well blockage which can be used regularly.     

地理数据产业化刍议

地理数据是地理信息系统的血液,因此地理空间数据的产业化直接关系到地理信息产业未来发展的前景。本文首先阐述了地理数据产业的定义和特征,然后分析了地理数据产业目前存在的问题,并从地理数据标准、地理数据质量、地理数据可视化、地理数据安全和保密、地理数据网络服务、地理数据投资、地理数据销售和地理数据应用等几方面提出了对地理数据产业发展的建议。     

First Spitzer observations of Neptune: Detection of new hydrocarbons

We present the first spectra of Neptune taken with the Spitzer Space Telescope, highlighting the high-sensitivity, moderate-resolution 10-20 μm (500-1000 cm⁻¹) spectra. We report the discovery of methylacetylene (CH₃C₂H) and diacetylene (C₄H₂) with derived 0.1-mbar volume mixing ratios of (1.2±0.1)×¹⁰⁻¹⁰ and (3±1)×¹⁰⁻¹² respectively.     

Urban flood susceptibility analysis using a GIS-based multi-criteria analysis framework

Natural Hazards - Pluvial flooding is a common type of natural hazard caused by rainfall events with high intensity and short duration, which may lead to substantial property damages,...