Long-term prediction of polar motion using a combined SSA and ARMA model

To meet the need for real-time and high-accuracy predictions of polar motion (PM), the singular spectrum analysis (SSA) and the autoregressive moving average (ARMA) model are combined for short- and long-term PM prediction. According to the SSA results for PM and the SSA prediction algorithm, the principal components of PM were predicted by SSA, and the remaining components were predicted by the ARMA model. In applying this proposed method, multiple sets of PM predictions were made with lead times of two years, based on an IERS 08 C04 series. The observations and predictions of the principal components correlated well, and the SSA \(+\) ARMA model effectively predicted the PM. For 360-day lead time predictions, the root-mean-square errors (RMSEs) of PMx and PMy were 20.67 and 20.42 mas, respectively, which were less than the 24.46 and 24.78 mas predicted by IERS Bulletin A. The RMSEs of PMx and PMy in the 720-day lead time predictions were 28.61 and 27.95 mas, respectively.     

一阶非线性泛函方程解的振动性(英文)

考虑两类带有分布型超前或滞后量的方程 (Ⅰ)x'(t)=a(t)x(t)+φ, (Ⅱ)x'(t)=a(t)x(t)-φ.其中β(t)>a(t),t+a(t)→∞(t→∞),f(x)和φ(u)是满足某些条件的非线性函数。 本文给出了方程(Ⅰ)和(Ⅱ)的所有解振动的若干充分性判定定理。作为应用,我们又讨论了如下方程的振动性,并给出了相应的判定准则。 (Ⅲ)x'(t)=a(t)x(t)+φ[sum from i=1 to n a_i(t)f(x(t+τ_i(t)))], (Ⅳ)x'(t)=a(t)x(t)-φ[sum from i=1 to n a_i(t)f(x(t+τ_i(t)))] 本文的结果是张炳根的若干结果的推广。     

长江经济带省域物流效率及时空演化研究

基于2007~2017年长江经济带物流行业发展数据,采用DEA模型、ArcGIS和空间自相关分析方法,测算长江经济带11个省市的物流效率值及时空演化规律。结果表明:2007~2017年长江经济带物流效率波动平缓,综合技术效率平均值为0.830,纯技术效率整体大于规模效率,下游地区的物流综合技术效率、纯技术效率和规模效率均大于中游和上游地区。空间上,长江经济带物流效率高值区主要分布在整个下游地区和中游部分地区,低值区则多为上游地区,整体呈“块状”分布。空间关联性上,2007~2017年,Global Moran's I显著为正,长江经济带各省市物流效率呈现空间正相关性,物流效率相近的省市在空间上集聚分布。最后,为促进长江经济带物流行业区域协调发展,提出如下建议:不断促进产业转型升级;加强区域合作,完善基础设施建设;加大内陆地区对外开放力度和建立大型的物流园区。     

基于全球土地退化零增长监测体系构建的中国沙化土地监测体系及效果评估

土地荒漠化是非常重要的生态环境问题,而科学评价荒漠化治理和零增长目标是否实现的必要前提是具有完善统一的评价体系。为此,联合国防治荒漠化公约（UNCCD）提出了土地退化零增长（LDN）的概念和监测指标。防治土地退化是中国的重要生态目标,中国已开展了多次全国土地荒漠化和沙化监测工作。但是,如何将这些监测结果用于土地退化的评估实践,尚未见报道。因此,本研究针对中国四大沙地,利用3期全国荒漠化和沙化监测数据,与基于UNCCD框架体系下的土地退化零增长（LDN）指标进行对比分析,并基于土地沙化程度变化趋势提出了中国沙化土地退化指标体系（CSLDN）。结果表明：UNCCD所提出的LDN监测指标与中国的荒漠化监测数据总体精度为0.51,中国沙化土地监测指标与LDN指标具有宏观一致性。此外,经本地优化后的CSLDN指标克服了低植被盖度区域LDN对土地退化和恢复的评价不准确的问题,更准确刻画了精细尺度空间内的土地动态变化状况,对土地退化防治意义重大。     

What do the solar activity indices represent?

Sunspot number, sunspot area, and radio flux at 10.7 cm are the indices which are most frequently used to describe the long‐term solar activity. The data of the daily solar full‐disk magnetograms measured at Mount Wilson Observatory from 19 January 1970 to 31 December 2012 are utilized together with the daily observations of the three indices to probe the relationship of the full‐disk magnetic activity respectively with the indices. Cross correlation analyses of the daily magnetic field measurements at Mount Wilson observatory are taken with the daily observations of the three indices, and the statistical significance of the difference of the obtained correlation coefficients is investigated. The following results are obtained: (1) The sunspot number should be preferred to represent/reflect the full‐disk magnetic activity of the Sun to which the weak magnetic fields (outside of sunspots) mainly contribute, the sunspot area should be recommended to represent the strong magnetic activity of the Sun (in sunspots), and the 10.7 cm radio flux should be preferred to represent the full‐disk magnetic activity of the Sun (both the weak and strong magnetic fields) to which the weak magnetic fields mainly contribute. (2) On the other hand, the most recommendable index that could be used to represent/reflect the weak magnetic activity is the 10.7 cm radio flux, the most recommendable index that could be used to represent the strong magnetic activity is the sunspot area, and the most recommendable index that could be used to represent the full‐disk magnetic activity of the Sun is the 10.7cm radio flux. Additionally, the cycle characteristics of the magnetic field strengths on the solar disk are given. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

汤原断陷第三纪地层研究新进展

主要从生物地层学、年代地层学和地球物理地层学三个方面,对汤原断陷近几年来地层研究的最新成果进行了简要论述,建立了１９个化石组合、亚组合,认为本区存在古新统和上新统;获得了１１个裂变径迹年龄数据;在地层倾角测井上识别出了４种沉积相变化模式;完善了本区第三系地层层序。     

赣南寨背A型花岗岩体的地球化学特征及其构造地质意义

赣南寨背岩体主要为黑云母钾长花岗岩,黑云母结晶晚于长石和石英,锆石群型地温测量标尺显示其结晶温度为８００℃～９００℃,表明寨背岩体形成于一种高温贫水的花岗质岩浆。岩石的化学成分特点为准铝质（Ａｌ２Ｏ３为１２．２１％～１２．６２％）,富硅（ＳｉＯ２为７５．６６％～７６．７４％）,偏碱（Ｎａ２Ｏ＋Ｋ２Ｏ为７．９３％～８．９０％）,ＦｅＯＴ／ＭｇＯ值高（５９～１４８）,ＣａＯ和ＭｇＯ含量低（分别为０．１０％～０．６５％和０．０１％～０．０２％）,富含ＲＥＥ（Ｅｕ除外,ΣＲＥＥ平均为５００μｇ／ｇ）,Ｙ、Ｇａ、Ｎｂ等高场强元素（ＨＦＳＥ）以及Ｆ,Ｓｒ和Ｂａ较低。这些特点与本区的Ｉ型和Ｓ型花岗岩有明显差别,是一种典型的Ａ２型花岗岩。寨背岩体Ｒｂ－Ｓｒ等时线年龄为１７６Ｍａ,与辉长岩、双峰式火山岩有密切的时空关系,表明赣南地区在燕山早期即进入拉张裂解阶段。     

五种经济海水鱼类的染色体研究

采用PHA体内注射──空气干燥制片法初步研究了5种海水鱼类的染色体。核型公式分别为鲻鱼、鲈鱼和黄姑鱼2n＝48t，NF＝48，其中鲻鱼的t1染色体、鲈鱼的t12染色体及黄姑鱼的t3染色体均为具明显次缢痕染色体，矛尾复虎鱼2n＝44，2m＋42st、t，NF＝46，其t18染色体为具次缢痕染色体；绿鳍马面2n＝40t，NF＝40，其中t14染色体具次缢痕。     

岩溶热储井间连通性的示踪研究

岩溶热储储层的不均匀性强,采灌井之间的连通性不易确定。示踪技术可以将运移参数量化,有效刻画储层流体的特征,研究回灌井和开采井之间的水力联系,包括导水通道,流体流速等信息,对长期回灌可能引起的开采井的冷却进行预测,是岩溶热储井间连通性研究十分有效的技术。本文以华北牛驼镇地热田雄县地区为例,针对蓟县系雾迷山组岩溶热储,采用荧光素钠示踪剂,进行了1口井注入,10口井观测的群井示踪试验。采用裂隙介质溶质运移模型,对示踪试验数据进行了解释,得到优势通道的长度、渗透流速、纵向弥散度、回收率等储层性质,获得了试验区内采灌井之间的连通特征。对调整采灌井布局提出了建议。     

Phenanthrene Removal from Aqueous Solution on Sesame Stalk‐based Carbon

This work explored the performance of sesame stalk‐based carbon prepared at different carbonization temperatures and activated by potassium hydroxide in the removal of phenanthrene from an aqueous solution. At a carbon concentration of 10 mg/32 mL and a carbonization temperature of 700°C, the removal efficiency of phenanthrene approached 100%. Furthermore, with the presence of acenaphthene and naphthalene as co‐contaminants, the removal efficiency of phenanthrene by the prepared carbon was 99.60%, which was comparable to that by the commercial carbon. Hydrophobic interactions influenced phenanthrene removal, and partitioning appeared to be the dominant mechanism for phenanthrene removal from aqueous solution by sesame stalk‐based carbon. The results obtained from this work should provide insight into the reuse of agricultural residues, and also suggest a new avenue for the removal of polycyclic aromatic hydrocarbons from contaminated water utilizing carbon prepared from agricultural residue.