东太平洋海隆13°N表层含金属沉积物物质组成与元素赋存状态     

荣坤波  曾志刚  武力  李康 《海洋科学》2018,42(7):70-79

为了解不同类型含金属沉积物在物质组成和元素赋存状态的差异,对东太平洋海隆13°N洋中脊两侧表层含金属沉积物(站号:E271和E53)进行了矿物学、地球化学分析,顺序提取实验,并与前人对轴部表层沉积物(站号:17A-EPR-TVG1)的研究结果作了对比分析。研究结果表明, E271和E53是远端含金属沉积物,由非浮力热液羽状流中颗粒物沉降所形成的;17A-EPR-TVG1沉积物是近喷口含金属沉积物,由黑烟囱或者热液硫化物丘状体崩塌、堆积,或者由热液羽状流中Fe-Mn氧化物和硫化物快速沉淀而形成的,近喷口沉积物比远端沉积物更富集Fe、Cu和Zn等元素。元素在两种含金属沉积物中的赋存状态基本相同,除了Fe,Cu,Zn,Mo和稀土元素(REE)等元素在远端沉积物中主要存在于Fe-Mn氧化物相,在近喷口沉积物中主要在残留相中。远端沉积物中REE页岩标准化配分模式与海水相似,表明REE主要来自海水,而近喷口沉积物中REE配分模式与热液流体相似,说明REE以高温热液流体来源为主。相关研究结果加深了对热液沉积作用研究的认识。  相似文献   

Review of pre-processing technologies for ice cores     

Wen-tao Du  Shi-chang Kang  Xiang Qin  Wei-jun Sun  Yu-lan Zhang  Yu-shuo Liu  Ji-zu Chen 《山地科学学报》2018,15(9):1950-1960

High-resolution ice core records covering long time spans enable reconstruction of the past climatic and environmental conditions allowing the investigation of the earth system’s evolution. Preprocessing of ice cores has direct impacts on the data quality control for further analysis since the conventional ice core processing is time-consuming, produces qualitative data, leads to ice mass loss, and leads to risks of potential secondary pollution. However, over the past several decades, preprocessing of ice cores has received less attention than the improvement of ice drilling, the analytical methodology of various indices, and the researches on the climatic and environmental significance of ice core records. Therefore, this papers reviews the development of the processing for ice cores including framework, design as well as materials, analyzes the technical advantages and disadvantages of the different systems. In the past, continuous flow analysis (CFA) has been successfully applied to process the polar ice cores. However, it is not suitable for ice cores outside polar region because of high level of particles, the memory effect between samples, and the filtration before injection. Ice core processing is a subtle and professional operation due to the fragility of the nonmetallic materials and the random distribution of particles and air bubbles in ice cores, which aggravates uncertainty in the measurements. The future developments of CFA are discussed in preprocessing, memory effect, challenge for brittle ice, coupling with real-time analysis and optimization of CFA in the field. Furthermore, non-polluting cutters with many different configurations could be designed to cut and scrape in multiple directions and to separate inner and outer portions of the core. This system also needs to be coupled with streamlined operation of packaging, coding, and stacking that can be implemented at high resolution and rate, avoiding manual intervention. At the same time, information of the longitudinal sections could be scanned and identified, and then classified to obtain quantitative data. In addition, irregular ice volume and weight can also be obtained accurately. These improvements are recorded automatically via user-friendly interfaces. These innovations may be applied to other paleomedias with similar features and needs.  相似文献   

Binary Star Fractions from the LAMOST DR4     

Zhi-Jia Tian  Xiao-Wei Liu  Hai-Bo Yuan  Bing-Qiu Chen  Mao-Sheng Xiang  Yang Huang  Chun Wang  Hua-Wei Zhang  Jin-Cheng Guo  Juan-Juan Ren  Zhi-Ying Huo  Yong Yang  Meng Zhang  Shao-Lan Bi  Wu-Ming Yang  Kang Liu  Xian-Fei Zhang  Tan-Da Li  Ya-Qian Wu  Jing-Hua Zhang 《天文和天体物理学研究(英文版)》2018,(5)

Stellar systems composed of single, double, triple or higher-order systems are rightfully regarded as the fundamental building blocks of the Milky Way. Binary stars play an important role in formation and evolution of the Galaxy. Through comparing the radial velocity variations from multiepoch observations, we analyze the binary fraction of dwarf stars observed with LAMOST. Effects of different model assumptions, such as orbital period distributions on the estimate of binary fractions,are investigated. The results based on log-normal distribution of orbital periods reproduce the previous complete analyses better than the power-law distribution. We find that the binary fraction increases with Teff and decreases with [Fe/H]. We first investigate the relation between α-elements and binary fraction in such a large sample as provided by LAMOST. The old stars with high [α/Fe] dominate with a higher binary fraction than young stars with low [α/Fe]. At the same mass, earlier forming stars possess a higher binary fraction than newly forming ones, which may be related with evolution of the Galaxy.  相似文献   

On the intrinsic shape of the gamma-ray spectrum for Fermi blazars     

Shi-Ju Kang  Qingwen Wu  Yong-Gang Zheng  Yue Yin  Jia-Li Song  Hang Zou  Jian-Chao Feng  Ai-Jun Dong  Zhong-Zu Wu  Zhi-Bin Zhang  Lin-Hui Wu 《天文和天体物理学研究(英文版)》2018,(5)

The curvature of the γ-ray spectrum in blazars may reflect the intrinsic distribution of emitting electrons, which will further give some information on the possible acceleration and cooling processes in the emitting region. The γ-ray spectra of Fermi blazars are normally fitted either by a single power-law(PL) or a log-normal(call Logarithmic Parabola, LP) form. The possible reason for this difference is not clear. We statistically explore this issue based on the different observational properties of 1419 Fermi blazars in the 3 LAC Clean Sample. We find that the γ-ray flux(100 Me V–100 Ge V) and variability index follow bimodal distributions for PL and LP blazars, where the γ-ray flux and variability index show a positive correlation. However, the distributions of γ-ray luminosity and redshift follow a unimodal distribution. Our results suggest that the bimodal distribution of γ-ray fluxes for LP and PL blazars may not be intrinsic and all blazars may have an intrinsically curved γ-ray spectrum, and the PL spectrum is just caused by the fitting effect due to less photons.  相似文献   

一种基于OpenMP的高效GPS卫星钟差实时估计方法     

高康  张守建  匡开发  曹新运  李建成 《大地测量与地球动力学》2018,38(6):571-576

提出基于单观测值的Kalman滤波快速计算方法,并引入共享存储并行编程（OpenMP）技术实现协方差快速更新,从而实现非差GPS卫星钟差的快速实时计算。均匀选取55个IGS参考站,计算2017-03-20~03-30采样率为60 s的卫星钟差。与IGS事后30 s钟差相比,两者具有很好的一致性,RMS互差优于0.5 ns。选取未参与钟差解算的10个IGS参考站进行精密单点定位,结果表明,实时静态PPP水平方向精度优于2 cm,高程方向精度为2~4 cm;实时动态PPP水平方向精度为2～4 cm,高程方向精度为4～6 cm,能够满足实时PPP的精度要求。该方法在主频1.2 GHz服务器上8线程并行模式下单历元耗时4 s,相比串行模式效率提升1/3。  相似文献   

Wave-induced Maintenance of Suspended Sediment Concentration during Slack in a Tidal Channel on a Sheltered Macro-tidal Flat,Gangwha Island,Korea     

Guan-hong Lee  KiRyong Kang 《Ocean Science Journal》2018,53(3):583-594

A field campaign was conducted to better understand the influence of wave action, in terms of turbulence and bed shear stress, on sediment resuspension and transport processes on a protected tidal flat. An H-frame was deployed in a tidal channel south of Gangwha Island for 6 tidal cycles during November 2006 with instrumentation including an Acoustic Doppler Velocimeter, an Acoustic Backscatter System, and an Optical Backscatter Sensor. During calm conditions, the current-induced shear was dominant and responsible for suspending sediments during the accelerating phases of flood and ebb. During the high-tide slack, both bed shear stress and suspended sediment concentration were reduced. The sediment flux was directed landward due to the scour-lag effect over a tidal cycle. On the other hand, when waves were stronger, the wave-induced turbulence appeared to keep sediments in suspension even during the high-tide slack, while the current-induced shear remained dominant during the accelerating phases of flood and ebb. The sediment flux under strong waves was directed offshore due to the sustained high suspended sediment concentration during the high-tide slack. Although strong waves can induce offshore sediment flux, infrequent events with strong waves are unlikely to alter the long-term accretion of the protected southern Gangwha tidal flats.  相似文献   

Sr掺杂Eu_1-xSr_xMnO₃体系的磁相变以及输运特性研究     

张佳佳  曹世勋  袁淑娟  李哲  康保娟  张金仓 《海洋学报》2010,32(9):6494-6500

对Eu_1-xSr_xMnO₃ (ESMO, x=0—1)体系的结构和磁性进行了系统的研究,结果表明Sr的掺入使EuMnO₃反铁磁母体的磁结构发生巨大的变化.通过磁化和电输运测量,深入探讨了高掺杂浓度Eu_0.4Sr_0.6MnO₃和Eu_0.3Sr_0.7MnO_{3相似文献}   

毛乌素沙区1961-2016年降水特征     

张雪琴  刘树林  冯坤  郭紫晨  康文平  陈翔  支莹 《中国沙漠》2019,39(6):141-150

基于毛乌素沙区10个气象站1961-2016年观测资料,应用Mann-Kendall方法和t检验法对各气象站年降水量进行了突变检验,借助小波分析讨论了各气象站年降水量的周期特征,根据降水量等值线划分结果对整个研究区分区分析了年、季、月和日尺度上的降水变化特征,并在两个时段上分析了季节性降水的差异。结果表明：毛乌素沙区年降水量空间特征差异明显,东部亚区呈上升趋势,中西部亚区呈下降趋势,但变化趋势不显著且无突变发生;降水年内分配不均,干湿季分明,降水集中在5-9月,夏秋季降水占全年降水比重大,季、月和日尺度降水量存在梯度递减变化;年降水量的年际变化过程存在多重时间尺度的自相似结构;近26年的冬春季降水增加显著,但降水波动幅度小于前30年。  相似文献   

福建省城市扩张与经济增长的互动关系研究     

黄康  戴文远 《云南地理环境研究》2019,(3):23-29

基于2000~2015年福建省9个设区市的城市建成区面积与非农GDP的历史数据,根据生态位理论将9个设区市分为4个等级,结合库兹涅兹曲线分析、协整检验及Granger因果关系分析、脱钩分析3种方法对不同等级城市之间的城市扩张和经济发展的互动关系进行了研究。研究表明:福建省城市生态位呈现东高西低,南高北低的空间格局;9个设区市均符合广义的库兹涅兹曲线关系,但只有高生态位城市全部符合倒“U”型曲线关系;福建省多数城市用地扩张与经济增长之间的Granger因果关系受区位、政策和决策等因素影响并不明显;福建省9个设区市的脱钩关系主要呈现为增长负脱钩、弱脱钩、强脱钩和增长连接4类,绝大多数城市多数时期以弱脱钩状态为主。  相似文献   

巨野煤田彭庄煤矿首采区减少煤损方法简析     

黄文峰  康延雷  冯超臣  刘峰 《山东国土资源》2009,25(12):1-2

山东鲁能菏泽煤电开发有限公司彭庄煤矿位于巨野煤田北部,是巨野煤田7个生产和在建煤矿（包括梁宝寺、彭庄、郭屯、赵楼、龙崮、万福、郓城等煤矿）的第一对投产的矿井。2006年8月开始试生产,2007年3月正式投产。彭庄煤矿2007年底核实保有资源量为12698．9万t,  相似文献