Burial fluxes and sources of organic carbon in sediments of the central Yellow Sea mud area over the past 200 years

Long-term changes of composition,sources and burial fluxes of TOC(total organic carbon) in sediments of the central Yellow Sea mud area and their possible affecting factors are discussed in this paper.Firstly,similarity analysis is employed to confirm that the carbon burial features resulted from two collected cores are typical in the central Yellow Sea mud area where YSWC(Yellow Sea Warm Current) is prevalent.On this basis,the burial flux of TOC here was considered to be 235.5–488.4 μmol/(cm2?a) since the first industrial revolution,accounting for about 70%–90% among burial fluxes of TC(total carbon) in the sediments.Compared TOC/TC ratio in the two cores with that in other marine sediments worldwide,we suggest that the growth of calcareous/non-calcareous organisms and dissolution of IC(inorganic carbon) are important factors controlling the TOC/TC ratio in sediment.Results of two-end mixed model based on δ13C data indicate that marine-derived organic carbon(OCa)is the main part among total burial organic carbon which accounts for a ratio over 85%.Due to the high TOC/TC ratio in the two cores,TC in the sediments also mainly exists as OCa,and the proportion of OCa is about 60%–80%.Away from the shore and relatively high primary production in upper waters are the main reasons that OCa is predominant among all burial OC in sediments of the central Yellow Sea mud area.Burial of OC in this mud area is probably mainly influenced by the human activities.Although the economic development during the late 19 th century caused by the first industrial revolution in China did not obviously increase the TOC burial fluxes in the sediments,the rise of industry and agriculture after the founding of new China has clearly increased the TOC burial flux since 1950 s.Otherwise,we also realize that among TC burial fluxes,TIC account for about 10%–30% in sediments of the central Yellow Sea mud area,so its burial could not be simply ignored here.Distinct from TOC burial,long-term TIC burial fluxes variations relate with climate changes more closely:the East Asian summer monsoon may influence the strength of the Huanghe River(Yellow River) flood,which could further affect the transport of terrestrial IC from land to the central Yellow Sea as well as the burial of these IC in the sediments.     

基于水下预置系统的深远海水下作战体系

通过分析强敌对我不断加大防范遏制力度,且水下装备技术朝信息化、智能化方向的快速发展, 提出构建基于水下预置系统的深远海水下作战能力对根本扭转我海上战略安全形势、在深远海有效拒止强敌的重大意义和难得机遇。在此基础上,进一步分析了基于水下预置系统的深远海水下作战体系担负的主要作战任务、基本构成及能力优势。选取东海方向大规模军事行动中,位第二岛链内外实施拒止作战作为典型场景,初步探索了体系基本兵力部署及总体运用,并对未来开展体系建设提出了思考建议。     

地学长江计划安徽实验中低频可控震源地震波信号提取方法评估

可控震源的激发过程精确可控、可重复性高。本文评估了重复激发形成的多道记录的信号增强方法,包括叠加方法和有效信号直接分离方法。相比线性叠加,加权叠加充分利用了有效信号的一致性,能进一步压制噪声,提高叠加记录的信噪比。相比时间域相位加权叠加,Semblance加权叠加更加稳定。时频域相位加权叠加能在时频域压制随机分散分布的噪声信号,叠加信号更加清晰。本文中,采用标准SVD分离获得的信号同线性叠加结果类似。本文利用密集分布的临时台阵评价地学长江计划安徽实验中低频可控震源在庐江第2激发点的激发效果。对比不同的处理流程发现,先互相关检测信号再进行时频域相位加权叠加能够取得最佳的处理效果,通过200多次重复激发,可以在50km范围内提取到较清晰的有效信号。     

勉略带三岔子蛇绿岩的变质特征及构造意义

勉略带是近年来秦岭造山带研究中揭示出来的代表晚古生代小洋盆的缝合带 ,组成复杂 ,它们经历了不同的变质、变形改造 ,构成了不同构造背景、不同构造层次、不同物质组成、具不同 PTt轨迹的蛇绿构造混杂带。文中 PTt轨迹揭示 ,秦岭造山带勉略带三岔子蛇绿岩中的变质辉长岩是由上地幔先处于伸展背景下等温快速降压、后又经历缓慢降压快速降温上升侵位的。变形前的早期变质可能发生在 60～ 70 km处的上地幔 ,然后变质辉长岩快速“底辟”构造侵位 ,上升至约4 0 km深处 ,可能与俯冲的冷洋壳并置 ,发生快速降温退变反应 ;因俯冲作用的开始 ,抑制了洋盆快速扩张 ,变质辉长岩在减速伸展环境下继续抬升减压 ;后期又由于仰冲推覆 ,最终出露地表。此外 ,变质作用 PTt轨迹还反映勉略小洋盆洋壳厚度与标准大洋型洋壳厚度差异较大。     

铁锰结核结壳生长过程的一种理论假设

铁锰结核成矿物质的直接来源是大洋底层水和沉积物孔隙水，结壳只有底层水，因此，底层水和孔隙水的物理化学特征就成为理解铁锰结核（壳）成矿作用特征与过程的关键。铁锰结核（壳）内部构造的两个明显特征是：①韵律性的环状纹层构造，和②树枝状构造，这两种构造是典型的远离平衡的非线性地质作用的产物。正常情况下，海底水—沉积物界面系统的底层水、孔隙水中Ｍｎ、Ｆｅ是不饱和的。因此，铁锰结核（壳）不可能在平衡状态下连续生长。本文提出铁锰结核（壳）生长的自反馈“振荡式”模型。     

灰色系统在电敏感区法粒度分析曲线外推技术中的应用

根据TAI型库尔特计数器单管粒度分析结果,利用灰色系统建立GM(1,1)预测模型,对样品频率曲线进行外推处理,可获得小于仪器基线通道阈值颗粒的体积百分比含量,并将结果与入重-出重法测定结果进行对比,精度较高。为电敏感区法粒度分析资料的外推处理提供了新的方法。     

In situ experiment on retrofit of school buildings by adding sandwich columns to partition brick walls

Many significantly strong earthquakes have occurred over the years in Taiwan, which have caused tremendous damage to primary and middle school buildings; the 921 Chi‐Chi earthquake was particularly devastating. According to statistics, 786 schools (1,958 classrooms) were damaged on September 21, 1999 during this earthquake event. The devastation showed that a lack of seismic performance is a common problem for existing school buildings in Taiwan. Therefore, the retrofit of existing school buildings has become an urgent issue in the prevention of possible damage in the future. The retrofit technique of adding sandwich columns to partition brick walls is proposed in this paper, and the feasibility of the proposed method was verified by in situ pushover tests of two real school buildings, one without and one with retrofit. The experimental and analytical results show that the sandwich column itself contributes significantly to the seismic capacity of the examined school building. Moreover, the analytical results yielded conservative capacity curves when compared with the experimental results. Copyright © 2013 John Wiley & Sons, Ltd.     

灌注桩结合三轴止水及内支撑的基坑围护设计

深基坑是一项理论复杂,学科综合性较高及风险较大的工程。工程中经常出现支撑体系失稳、围护结构失稳、坑壁漏水、坑底隆起等现象。以上海某深基坑工程为对象,分析了深基坑围护方案的选型要点,总结了深基坑围护设计中关键的计算与验算内容。最后对比分析了设计计算结果与实际监测数据结果,证明了所采取的围护形式的有效性,希望能为今后类似工程提供一些借鉴和参考。     

Characterization of ribulose-1, 5-bisphosphate carboxylase/oxygenase and transcriptional analysis of its related genes in Saccharina japonica (Laminariales,Phaeophyta)

Saccharina japonica is a common macroalga in sublittoral communities of cold seawater environments,and consequently may have highly effi cient ribulose-1,5-bisphosphate carboxylase/oxygenase(Rubisco)activity for carbon assimilation.In our study,we cloned the full-length Rubisco gene from S.japonica(SJ-rbc).It contained an open reading frame for a large subunit gene(SJ-rbcL)of 1 467 bp,a small subunit gene(SJ-rbcS)of 420 bp,and a SJ-rbcL /S intergenic spacer of 269 bp.The deduced peptides of SJ-rbcL and SJ-rbcS were 488 and 139 amino acids with theoretical molecular weights and isoelectric points of 53.97 kDa,5.81 and 15.84 kDa,4.71,respectively.After induction with 1 mmol/L isopropyl-β-Dthiogalactopyranoside for 5 h and purifi cation by Ni 2+ affi nity chromatography,electrophoresis and western blot detection demonstrated successful expression of the 55 kDa SJ-rbcL protein.Real-time quantitative PCR showed that the mRNA levels of SJ-rbcL in gametophytes increased when transferred into normal growth conditions and exhibited diurnal variations: increased expression during the day but suppressed expression at night.This observation implied that Rubisco played a role in normal gametophytic growth and development.In juvenile sporophytes,mRNA levels of SJ-rbcL,carbonic anhydrase,Calvin-BensonBassham cycle-related enzyme,and chloroplast light-harvesting protein were remarkably increased under continuous light irradiance.Similarly,expression of these genes was up-regulated under blue light irradiance at 350 μmol/(m 2·s).Our results indicate that long-term white light and short-term blue light irradiance enhances juvenile sporophytic growth by synergistic effects of various photosynthetic elements.     

黄淮海地区乡村功能类型及其地域模式*

黄准海地区农业发展历史悠久,由于地方性自然和经济条件的差别,乡村经济在产业功能上存在明显的地域差异。本文以该区辖属的364个县(市)为地域单元,研究其乡村功能类型,并对不同功能类型的空间分布、功能特征及其经济发展的地域模式作了探讨。