连云港海相软土不排水强度特征

连云港地区软土为碱性环境下沉积的非均质海积软土,软土抗剪强度具有固有各向异性。采用三轴不固结不排水剪切（UU）试验、无侧限抗压强度（UTC）试验、快剪试验和原位十字板剪切（FVT）试验4种方法,对连云港地区软土的不固结不排水抗剪强度特征进行了研究。结果表明：土体水平剪切面强度最低,竖直面抗剪强度最高;土体制样采用垂直方向的切取试样方式时,土体强度最高。根据三轴UU试验得出的黏聚强度和内摩擦角基于土体单元极限平衡理论恢复了土体剪切破坏时的应力状态,计算出土体实际抗剪强度。三轴UU试验得出的抗剪强度平均值约为13.13 kPa,试样破裂面与水平面的夹角在45.1°~45.7°区间最为集中。UTC试验测得的土体平均抗剪强度近似等于三轴UU试验测得的平均抗剪强度。FVT试验测得软土抗剪强度平均值为19.72 kPa,与三轴UU试验和UTC试验得出的抗剪强度平均值相比高了约6.60 kPa,这种现象与室内试验试样的机械扰动、土体应力状态改变和剪切面特征有关。     

山东沿海降雨云系宏观特征及人工增雨潜力的估算

针对山东省飞机人工增雨作业的实际情况，分析了山东沿海地区的降雨特征，统计了沿海云层的宏观物理量，分析了莱州湾、黄海北部和东南沿海３个地区云与降水的关系，对主要降雨天气系统计算了降雨效率及增潜力，增雨潜力在４２．５５％－６８．７９％。通过对天气系统中水汽垂直分布的分析，为飞机在山东沿海地区增雨作业最佳催化层次的选择提供了信。     

南海北部表层颗粒有机碳的季节和年际变化遥感分析

海洋颗粒有机碳（POC）是海洋固碳的一个关键参数。为了研究南海北部陆架及海盆表层POC浓度的时空分布特征以及变化趋势,本文利用2009-2011年4个季节的实测数据,对NASA发布的MODIS/AQUA卫星月平均POC遥感产品,进行了验证和校正;并利用校正后的遥感数据分析了2003-2014年POC的时空分布特征和变化趋势。发现POC遥感产品与南海北部实测数据具有较好的线性关系（R2=0.72）,但存在系统性偏高,需利用实测数据对遥感数据进行区域性校正。分析校正后的遥感数据发现,南海北部陆架POC浓度较高,平均为（33.34±8.02）mg/m3;吕宋海峡西南海域浓度较低,平均为（29.25±6.20）mg/m3;中央海盆区浓度最低,平均为（27.02±4.84）mg/m3。春夏季POC浓度较低,最低值一般出现在5月,冬季（12月至翌年1月）POC浓度达到最高。利用2003-2014年的长时间序列遥感叶绿素（Chl a）和海表温度（SST）、混合层深度（MLD）模式数据,以及实测数据对南海北部POC浓度的影响机制进行了分析。发现POC与Chl a在秋冬呈现较好的相关关系（R2=0.51）,但在春夏季较离散,表明秋冬季生物作用对POC影响较大。2003-2014年期间,POC与Chl a、MLD及SST存在明显的年际变化,但并没有显著的上升或下降趋势。     

海南岛莺歌海近岸的潮汐不对称与潮致余流研究

潮汐不对称与潮致余流在河口海岸区的物质输运中扮演着重要角色。已往的研究表明,在驻波占主导的河口海湾中,涨落潮的历时不对称与流速不对称有较为良好的对应关系。而潮致余流主要由地形与潮波的非线性作用所致。本研究以海南岛莺歌海附近为代表,结合实际观测与数值模型,研究复杂地形的开阔近岸区的潮汐不对称与潮致余流。结果表明,在莺歌海近岸区,涨落潮历时不对称皆表现为涨潮历时短于落潮历时,而流速不对称则出现复杂的空间变化。对流速不对称的机制分解表明,研究区的流速不对称主要由K₁、O₁与M₂的相互作用,以及潮余流与各潮汐分潮的相互作用所控制。其中前者产生涨潮流速大于落潮流速的涨潮优势,而后者则与余流的方向相对应,出现多个涨潮优势与落潮优势的区域。总体而言,研究区的流速不对称由余流与各潮汐分潮的相互作用所决定。这表明,采用涨落潮历时的不对称来确定潮汐不对称的方法在开阔近海区可能并不适用。对潮致余流的研究表明,研究区的欧拉余流远大于斯托克斯余流。欧拉余流表现为多个顺时针与逆时针的涡流。涡流分布与地形具有较好的对应关系,潮流沙脊区多发育顺时针涡流,而深槽区则以发育逆时针涡流为主。摩擦力在涡流的发育中起着重要作用。     

Distributed estimation and analysis of precipitation recharge coefficient in strongly-exploited Beijing plain area,China

The precipitation recharge coefficient(PRC), representing the amount of groundwater recharge from precipitation, is an important parameter for groundwater resources evaluation and numerical simulation. It was usually obtained from empirical knowledge and site experiments in the 1980 s. However, the environmental settings have been greatly modified from that time due to land use change and groundwater over-pumping, especially in the Beijing plain area(BPA). This paper aims to estimate and analyze PRC of BPA with the distributed hydrological model and GIS for the year 2011 with similar annual precipitation as long-term mean. It is found that the recharge from vertical(precipitation + irrigation) and precipitation is 291.0 mm/yr and 233.7 mm/yr, respectively, which accounts for 38.6% and 36.6% of corresponding input water. The regional mean PRC is 0.366, which is a little different from the traditional map. However, it has a spatial variation ranging from –7.0% to 17.5% for various sub-regions. Since the vadose zone is now much thicker than the evaporation extinction depth, the land cover is regarded as the major dynamic factor that causes the variation of PRC in this area due to the difference of evapotranspiration rates. It is suggested that the negative impact of reforestation on groundwater quantity within BPA should be well investigated, because the PRC beneath forestland is the smallest among all land cover types.     

Dye adsorption on electrochemical exfoliated graphene oxide nanosheets: pH influence,kinetics and equilibrium in aqueous solution

Graphene oxide nanosheets were synthesized by electrochemical exfoliation. X-ray diffraction, scanning electron microscopy, atomic force microscopy, Raman spectrometry and Fourier transform infrared spectrometry were used to characterize crystal structure, particle size, thickness and function groups of the nanosheets. The nanosheets were examined for adsorption of methyl orange, an anionic dye, in aqueous solution at different pHs and temperatures. The maximum adsorption capacity of methyl orange on graphene oxide nanosheets obtained from the Langmuir isotherm was 138.69 mg/g at pH 2.0, which is larger than that of other carbonaceous adsorbents. The large adsorption affinity of graphene oxide nanosheets to methyl orange might be due to the presence of hydrogen bonding and π–π interaction between methyl orange and graphene oxide nanosheets. Adsorption kinetics followed a pseudo-second-order kinetic model, and the isotherm adsorption results were fitted with Langmuir isotherm model in a monolayer adsorption manner. The thermodynamic studies indicated that the adsorption reaction was a spontaneous physisorption process.     

Determination of the thicknesses of oil films in micro- and nano-pores in tight oil sands: an example from the southern Songliao Basin,NE China

An experimental method of field-emission environmental scanning electron microscope (ESEM) coupled with the energy dispersive spectrum (EDS) to determine the thickness of oil films in the micro- and nano-pores of tight oil sands was proposed to overcome the limitations of current methods. First, we got the data of the detection range volumes, elemental mass percentages, and elemental atomic percentages using the EDS, and then calculated the volumes of oil films in the detection range according to the elemental mass percentages and the elemental atomic percentages of carbon. After that, we calculated the surface areas of oil films using the pore size data (lengths, widths, and depths) detected by ESEM. The thicknesses of oil films in the pores equaled the volumes divided by the surface areas. An analysis of tight oil samples from the Quan 4 Segment of in the southern Songliao Basin, NE China confirmed that the oil in the micro- and nano-pores had two main forms: oil films and oil droplets. The thicknesses of the oil films ranged from about 400 nm to 2 μm, while the thicknesses of the oil droplets ranged from about 200 to 700 nm.     

地震仪器设备管理系统的设计与实现

利用Java语言,使用Microsoft SQL Server 2005数据库,利用MyEclipse工具研发地震仪器设备管理系统.使用该系统进行台站仪器设备信息管理,便于保存、查询、更新信息,实现数据资料的完整、准确、长期保存,工作效率增加.     

Phosphatic microspherules and their geobiological implications from the Frasnian-Famennian transition at the Yangdi section,Guilin, South China

Abundant perfectly-preserved phosphatic microspherules have been discovered across the Frasnian-Famennian(F-F)transition from the Yangdi section in Guilin,Guangxi,South China.They are mostly spherical or elliptical in shape and about 150μm in diameter with smooth exterior surfaces.Each microspherule consistently possesses a small dimple on the surface.The internal texture of microspherules consists of concentric light-colored apatite and dark-colored organic matter bands alternating around a central core.Conodonts have also been found preserved together with phosphatic microspherules in the same horizon,and the abundance of the former is obviously higher than that of the latter.Laser Raman spectral studies show close similarities in spectral patterns between the outer shells of phosphatic microspherules and the blade of the conodont genus Palmatolepis sp.,as well as between the microspherule nucleus and the platform of the same conodont genus.Furthermore,the statistical results and geochemical data demonstrate that the elevated abundance of phosphatic microspherules roughly coincides with the blooms of bacteria and algae,but is later than the sharp increase of oceanic nutrients.The phosphatic microspherules are interpreted here to be the‘otoliths’secreted by conodont animals based on the compositional similarities between phosphatic microspherules and conodonts and their interrelated abundances.In addition,an analogous study reveals morphological and textural similarities between fish otoliths and phosphatic microspherules.The formation of phosphatic microspherules is probably related to seawater eutrophication.We speculate that the explosive growth of bacteria and algae is probably caused by the enrichment of nutrients that is most likely associated with the increase of terrestrial inputs,submarine hydrothermal activities or the upwelling anoxic bottom waters in the late Devonian,which would stimulate the conodont animals to secrete phosphatic microspherules—the‘otoliths’of conodont animals.This study reveals the coupling relationship between organisms and environments from the perspective of phosphatic microspherules and provides new evidence for the cause of faunal crisis during the Late Devonian F-F transition.     

A 30 meter land cover mapping of China with an efficient clustering algorithm CBEST

Remote sensing based land cover mapping at large scale is time consuming when using either supervised or unsupervised classification approaches. This article used a fast clustering method—Clustering by Eigen Space Transformation(CBEST) to produce a land cover map for China. Firstly, 508 Landsat TM scenes were collected and processed. Then, TM images were clustered by combining CBEST and K-means in each pre-defined ecological zone(50 in total for China). Finally, the obtained clusters were visually interpreted as land cover types to complete a land cover map. Accuracy evaluation using 2159 test samples indicates an overall accuracy of 71.7% and a Kappa coefficient of 0.64. Comparisons with two global land cover products(i.e., Finer Resolution Observation and Monitoring of Global Land Cover(FROM-GLC) and GlobCover 2009) also indicate that our land cover result using CBEST is superior in both land cover area estimation and visual effect for different land cover types.