应用X射线衍射-激光拉曼光谱-电子探针等分析测试技术研究旬阳朱砂玉的矿物学特征

近年来外观形似鸡血石的红色朱砂玉备受关注,其中吉林、贵州、青海等地这种红色岩石已有矿物成分、岩性等相关方面的研究。本文利用常规宝石常数测定手段、偏光显微镜、X射线粉晶衍射仪、激光拉曼光谱仪、电子探针等分析测试技术,对陕西旬阳朱砂玉的矿物学和宝石学特征进行了研究。结果表明,该产地朱砂玉的矿物成分以石英、辰砂为主,含有少量的方解石、白云石、重晶石、黄铁矿;其中主要矿物成分辰砂的颜色随铁含量的增加而逐渐加深;矿物结构以碎屑结构、粒状变晶结构、穿插交代结构为主。根据矿物成分以及矿床成因的研究分析,初步认为陕西旬阳朱砂玉属于沉积-热液-强烈改造型矿床。该地区的朱砂玉与鸡血石的相似之处在于矿物的主要成分都含有辰砂,致使外观品质上具有一定的相似性,但具体矿床成因以及矿物成分有着明显的差别:旬阳朱砂玉产于沉积-热液-强烈改造型矿床中,其“地”主要矿物成分为石英岩,“血”为辰砂;而浙江昌化和内蒙古巴林鸡血石均产于中生代交代蚀变酸性火山岩的次级断裂小构造中,其“地”主要为地开石、高岭石、叶腊石,“血”为辰砂。此次研究采用多种分析测试手段为旬阳朱砂玉与鸡血石的鉴别提供了可靠的依据。     

COSMIC与FY-3C掩星电离层反演的比较

利用基于TEC的电子密度廓线反演方法,对2014年12月31日的COSMIC和FY-3C掩星任务的电离层掩星相位数据进行处理,将反演的电子密度廓线及电离层峰值参数分别与两个掩星任务的官方产品进行比较,发现两个掩星任务的反演结果与官方产品均具有较好的一致性.其中COSMIC反演结果与CDAAC官方产品的一致性略好于FY-3C反演结果与NSMC官方产品的一致性,且两个任务的NmF2的反演质量均优于hmF2的反演质量.但与COSMIC不同,FY-3C掩星电离层相位数据进行反演处理之前有必要进行滤波平滑预处理,且由于FY-3C非掩星时段的相位数据量太少,反演过程中不建议对TEC进行改正.     

Asteroseismology of DAV white dwarf stars and G29-38

Asteroseismology is a powerful tool used for detecting the inner structure of stars, which is also widely used to study white dwarfs. We discuss the asteroseismology of DAV stars. The period-to-period fitting method is discussed in detail, including its reliability in detecting the inner structure of DAV stars. If we assume that all observed modes of some DAV stars are the l = I cases, the errors associated with model fitting will be always large. If we assume that the observed modes are com- posed of I = 1 and 2 modes, the errors associated with model fitting in this case will be small. However, there will be modes identified as l = 2 that do not have ob- served quintuplets. G29-38 has been observed spectroscopically and photometrically for many years. Thompson et al. made 1 modes identifications in the star through the limb darkening effect. With 11 known I modes, we also study the asteroseismology of G29-38, which reduces the blind l fittings and is a fair choice. Unfortunately, our two best-fitting models are not in line with the previous atmospheric results. Based on factors like only a few observed modes, stability and identification of eigenmodes, identification of spherical degrees, construction of physical and realistic models and so on, detecting the inner structure of DAV stars by asteroseismology needs further development.     

Molecular outflows and gas rotation associated with G20.08-0.14N

We present the results of a high-resolution study with the Submillimeter Array （SMA） toward the massive star-forming complex G20.08-0.14N. With the SMA data, we have detected and analyzed the transitions in the 12CO （3-2） and 12CO （2-1） molecular lines as well as CHaCN. The millimeter observations reveal highly collimated bipolar molecular outflows, traced by high-velocity 12CO （2-1） and 12CO （3-2） emissions. Using a rotation temperature diagram, we derive that the rota- tional temperature and the column density of CHaCN are 244 K and 1.2 ~ 1015 cm-2, respectively. We also suggest that the minor outflow is probably driven by the hy- percompact （HC） HII region A that is inside. We find the molecular gas （traced by ClrO, SO, CH3OH and SO2） surrounding G20.08-0.14N appears to be undergoing bulk rotation. The HCHII region A that is inside is most probably the main source of accretion and heating for G20.08-0.14N.     

基于反演基岩地震波的场地调整系数估计

基于KiK-net台阵中73个台站的一维土层模型和从不同地震中筛选的262条地表加速度记录,按照峰值加速度的分档标准和场地分类原则,将这些记录分成了28组.采用一维土层地震反应分析的等效线性化方法,反演计算了基岩输入加速度.通过分别计算各组基于有效峰值加速度EPA的场地放大倍数,并得到了各类场地的有效峰值加速度的调整系...     

The technique of quasi-lossless compression of the remote sensing image

In this paper, the technique of quasi-lossless compression based on the image restoration is presented. The technique of compression described in the paper includes three steps, namely bit compression, correlation removing and image restoration based on the theory of modulation transfer function (MTF). The quasi-lossless compression comes to a high speed. The quality of the reconstruction image under restoration is up to par of the quasi-lossless with higher compression ratio. The experiments of the TM and SPOT images show that the technique is reasonable and applicable.     

Hydrology of channelized and natural headwater streams / Hydrologie de cours d'eau recalibrés et naturels de tête de bassin

Abstract

Understanding hydrology of channelized and natural headwater streams is paramount for maintaining ecosystem function and natural flow regimes. Two channelized and two natural headwater streams located in Upper Big Walnut Creek (UBWC) watershed in Ohio, USA, were instrumented to facilitate measurement, characterization and comparison of hydrology to the accepted paradigm for headwater hydrology. Data were collected at 10-min intervals from 1 January 2005 to 31 December 2006. Differences in flow magnitudes (average, low and high) were generally greater (P < 0.05) in the channelized streams. Frequency of zero discharge and out-of-bank discharge was significantly greater in the natural streams. Zero discharge occurred in summer and out-of-bank flows occurred in winter. Rate of change variables indicated that channelized streams respond more quickly to rainfall, have significantly greater peak flows, and have slower recession times. In contrast, natural streams tend to be more “flashy”. The findings were generally consistent with the accepted paradigm for headwater hydrology and attributed to stream type, presence of subsurface drainage, potential connection to groundwater, and differences in riparian vegetation. The design and installation of management practices that influence hydrology should consider the potential impacts of altering stream hydrology. Management practices such as water-table management have the potential and show promise in altering the hydrology of channelized streams to resemble the hydrology of natural streams.     

Probabilistic seismic hazard analysis in Nepal

The seismic ground motion hazard for Nepal has been estimated using a probabilistic approach. A catalogue of earthquakes has been compiled for Nepal and the surrounding region （latitude 26% N and 31.7% N and longitude 79° E and 90° E） from 1255 to 2011. The distribution of catalogued earthquakes, together with available geological and tectonic information were used to delineate twenty-three seismic source seismic source information and probabilistic earthquake hazard prediction relationship, peak ground accelerations （PGAs） have zones in Nepal and the surrounding region. By using the parameters in conjunction with a selected ground motion been calculated at bedrock level with 63%, 10%, and 2% probability of exceedance in 50 years. The estimated PGA values are in the range of 0.07-0.16 g, 0.21 0.62 g, and 0.38-1.1 g for 63%, 10%, and 2% probability of exceedance in 50 years, respectively. The resulting ground motion maps show different characteristics of PGA distribution, i.e., high hazard in the far-western and eastern sections, and low hazard in southern Nepal. The quantified PGA values at bedrock level provide information for microzonation studies in different parts of the country.     

Effect of seismic super-shear rupture on the directivity of ground motion acceleration

The effect of seismic super-shear rupture on the directivity of ground motions using simulated accelerations of a vertical strike-slip fault model is the topic of this study. The discrete wave number/finite element method was adopted to calculate the ground motion in the horizontal layered half space. An analysis of peak ground acceleration （PGA） indicates that similar to the sub-shear situation, directivity also exists in the super-shear situation. However, there are some differences as tbllows： （1） The PGA of the fault-normal component decreases with super-shear velocity, and the areas that were significantly affected by directivity in the PGA field changed from a cone-shaped region in the forward direction in a sub-shear situation to a limited near-fault region in a super-shear situation. （2） The PGA of the fault-parallel and vertical component is not as sensitive as the fault-normal component to the increasing super-shear velocity. （3） The PGA of the fault-normal component is not always greater than the fault-parallel component when the rupture velocity exceeds the shear wave velocity.     

http://www.sciencedirect.com/science/article/pii/S1674987112000084

Seismic anisotropy and its main features along the convergent boundary between Africa and Iberia are detected through the analysis of teleseismic shear-wave splitting.Waveform data generated by 95 teleseismic events recorded at 17 broadband stations deployed in the western Mediterranean region are used in the present study.Although the station coverage is not uniform in the Iberian Peninsula and northwest Africa,significant variations in the fast polarization directions and delay times are observed at stations located at different tectonic domains.Fast polarization directions are oriented predominantly NW-SE at most stations which are close to the plate boundary and in central Iberia;being consistent with the absolute plate motion in the region.In the northern part of the Iberian Peninsula,fast velocity directions are oriented nearly E—W;coincident with previous results.Few stations located slightly north of the plate boundary and to the southeast of Iberia show E—W to NE-SW fast velocity directions,which may be related to the Alpine Orogeny and the extension direction in Iberia.Delay times vary significantly between 0.2 and 1.9 s for individual measurements,reflecting a highly anisotropic structure beneath the recording stations.The relative motion between Africa and Iberia represents the main reason for the observed NW-SE orientations of the fast velocity directions.However,different causes of anisotropy have also to be considered to explain the wide range of the splitting pattern observed in the western Mediterranean region.Many geophysical observations such as the low Pn velocity,lower lithospheric Q values,higher heat flow and the presence of high conductive features support the mantle How in the western Mediterranean,which may contribute and even modify the splitting pattern beneath the studied region.