Holocene landscape evolution and its impact on the neolithic and bronze age sites in the Shangqiu area,Northern China

The Shangqiu area, situated on the alluvial plain of the lower Yellow River, is traditionally considered the center of the predynastic and early Shang culture. Archaeologic remains dating to predynastic and dynastic Shang periods, however, have remained elusive. The current pattern of Neolithic and Bronze Age sites is characterized by their upland settings; and it has been often assumed that the area had the same landscape from the Neolithic through recent historic time. The potential impact of geomorphic processes on these early sites has been hardly considered in developing archaeologic models of temporal and spatial distribution of these sites. This article first presents a reconstruction of the Holocene floodplain history in the archaeologically significant area. On the basis of stratigraphy and sedimentology, a Holocene landscape evolution model is constructed to explore the interrelationship between evolving landscape and archaeologic record of the Neolithic and Bronze Age. The prolonged landscape stability from very late Pleistocene or early Holocene to 2000 yr B. P. provided potential Neolithic and Bronze Age human occupation with a favorable physical environment. After 2000 yr B. P., the hydrologic regime changed and the floodplain experienced 2-3 m of gradual vertical accretion during the following millennium. In response to the dramatic change of hydro-logic regime after the early 12th century A. D., a new floodplain formed by dominantly overbank deposition, and the old floodplain surfaces are covered by as much as ten meters of the younger alluvium. As a result, a pronounced effect has been imposed on the preservation, visibility, and discovery of the Neolithic and Bronze Age sites, including those sites of predynastic and early Shang phases. Thus, much difficulty has been imparted to our understanding of the configuration of these early archaeologic sites. This study demonstrates the usefulness of landscape reconstruction in developing settlement models of Neolithic and Bronze age sites in the area.     

海南岛福山凹陷古近系流沙港组沉积相

古近系流沙港组沉积时期是海南岛福山凹陷的主要成盆期,沉陷幅度较大,地势较陡,由此导致流沙港组深水湖泊沉积和辫状河三角洲沉积相当发育。通过对岩心、测井和地震等资料的综合分析,分别对流沙港组3个岩性段的沉积相进行了研究。单井沉积相和平面沉积相分析表明流沙港组主要发育辫状河三角洲相和湖泊相,并可进一步划分出7种亚相和13种微相。流三段沉积时期辫状河三角洲沉积最为发育,约占研究区总面积的一半,仅在研究区北部为半深湖亚相—深湖亚相分布区。流二段沉积时期是福山凹陷最大湖侵期,深水湖泊相最为发育,研究区北半部几乎全为深湖亚相—半深湖亚相分布区。流二段沉积之后,凹陷周缘发生较大范围隆升,因此,流一段沉积时期的沉积范围比流二段沉积时期小得多,但其沉积相展布格局与流二段沉积时期仍比较相似。通过对ZTR指数(代表锆石、金红石、电气石三种重矿物在透明重矿物中所占的比例)等值线图、砂(砾)岩百分含量等值线图及沉积相展布格局等分析认为,流沙港组沉积时期的物源主要来自南方的海南隆起,东、西方向还存在2个次要物源。     

鲁西金岭矽卡岩型铁矿区早白垩世石英闪长岩成因:年代学和地球化学证据

金岭岩体是鲁西地区代表性的中生代侵入杂岩体,与金岭矽卡岩型铁矿的成因密切相关.为了解石英闪长岩的成因及与矽卡岩铁矿成矿关系,本次研究对金岭杂岩体中的石英闪长岩进行了年代学、地球化学及锆石Lu—Hf同位素和角闪石矿物微区成分的系统研究.LA-ICP-MS锆石U-Pb年代学显示石英闪长岩加权平均年龄为(128±1)Ma,侵...     

国外无人反水雷特点及关键技术分析

许多国家将水雷视为一种重要的水中兵器,用于封锁对手、对抗强敌。针对现有反水雷装备存在的危险性高、部署速度慢、作战效率低等问题,国外海军将无人技术为代表的高新技术应用到反水雷领域,推出了多种新概念无人反水雷装备,综合运用猎、扫等多种手段,构建空中、水面、水下立体的无人反水雷装备体系,实现快速、安全、高效的反水雷作战能力,对未来反水雷作战产生重大影响。     

纳滤分离铝锂过程研究

本文探讨了纳滤分离Al~(3+)和Li~+的可行性,研究了含盐量和铝锂比对分离效率的影响,提出了从锂云母浸出液中分离回收锂的新方法。实验结果表明,纳滤膜对Al~(3+)和Li~+的截留率随含盐量的升高而降低,其中Li~+始终呈现负浓度梯度扩散的趋势,而Al~(3+)的截留率始终稳定在99%以上。当含盐量为45 g/L时,铝锂分离因子最高可达248.33,膜面相应Zeta电位的绝对值达到最大。随着溶液中铝锂比的变化,Al~(3+)和Li~+的截留率分别在不同铝锂比的条件下出现拐点,溶液的pH呈现先下降后上升最后下降的复杂趋势。本实验研究发现,DK膜能够在酸性环境下实现高效的铝锂分离和锂的浓缩,从而为锂云母浸出液中锂的提取提供新的思路。     

Salinivibrio sp.YH4胞外丝氨酸蛋白酶EYHS耐盐性及生物信息学分析

摘要：目的 探讨菌株Salinivibrio sp.YH4分泌的丝氨酸蛋白酶EYHS的耐盐性及结构特征。方法 明胶底物酶谱法分析EYHS的耐盐性。应用生物信息学手段对EYHS及6种耐盐的S8家族丝氨酸蛋白酶结构特征进行分析。结果 EYHS在4 mol/L的NaCl溶液中仍具有活性,属于耐盐蛋白酶。EYHS及6种S8家族丝氨酸蛋白酶分子表面的loop区等无规则卷曲所占比例较高,α-螺旋与β-片层则主要位于酶分子内部。EYHS分子表面酸性氨基酸含量较高,且具有弱疏水内核。多序列比对发现蛋白酶的催化三联体两侧存在高度保守的基序和保守的极性氨基酸及芳香族氨基酸,并存在多个保守的Gly与Ala。同源模建和表面电荷分布显示,α螺旋和β片层围成了蛋白酶的催化腔,EYHS活性中心包含由Asp32、His65与Ser215组成的催化三联体,且催化位点区域表面静电势为负。结论 上述结构特征可能有助于耐盐丝氨酸蛋白酶EYHS在高盐环境下维持其稳定性和适度柔性,并有助于其催化功能的发挥,为深入研究耐盐丝氨酸蛋白酶的高盐环境适应性提供了一定的理论依据。     

Coupling numerical simulation with remotely sensed information for the study of frozen soil dynamics

The acquisition of spatial-temporal information of frozen soil is fundamental for the study of frozen soil dynamics and its feedback to climate change in cold regions. With advancement of remote sensing and better understanding of frozen soil dynamics, discrimination of freeze and thaw status of surface soil based on passive microwave remote sensing and numerical simulation of frozen soil processes under water and heat transfer principles provides valuable means for regional and global frozen soil dynamic monitoring and systematic spatial-temporal responses to global change. However, as an important data source of frozen soil processes, remotely sensed information has not yet been fully utilized in the numerical simulation of frozen soil processes. Although great progress has been made in remote sensing and frozen soil physics, yet few frozen soil research has been done on the application of remotely sensed information in association with the numerical model for frozen soil process studies. In the present study, a distributed numerical model for frozen soil dynamic studies based on coupled water-heat transferring theory in association with remotely sensed frozen soil datasets was developed. In order to reduce the uncertainty of the simulation, the remotely sensed frozen soil information was used to monitor and modify relevant parameters in the process of model simulation. The remotely sensed information and numerically simulated spatial-temporal frozen soil processes were validated by in-situ field observations in cold regions near the town of Naqu on the East-Central Tibetan Plateau. The results suggest that the overall accuracy of the algorithm for discriminating freeze and thaw status of surface soil based on passive microwave remote sensing was more than 95%. These results provided an accurate initial freeze and thaw status of surface soil for coupling and calibrating the numerical model of this study. The numerically simulated frozen soil processes demonstrated good performance of the distributed numerical model based on the coupled water-heat transferring theory. The relatively larger uncertainties of the numerical model were found in alternating periods between freezing and thawing of surface soil. The average accuracy increased by about 5% after integrating remotely sensed information on the surface soil. The simulation accuracy was significantly improved, especially in transition periods between freezing and thawing of the surface soil.     

东北地区大气污染物源排放时空特征：基于国内外清单的对比分析

基于国内外4类常用的污染源排放清单数据（EDGAR：全球大气研究排放数据库;CEDS：社区排放数据系统;MIX：亚洲排放清单;PKU-FUEL：全球燃料排放数据）,对东北区域5类人为排放源（工业源、能源、交通运输源、生活民用源和农业源）的8种污染物（PM_2.5、PM₁₀、SO₂、NO_x、NMVOCs、NH₃、OC和BC）从排放总量、来源贡献和时空分布特征等方面进行对比分析。结果表明：东北污染物排放主要以SO₂、NO_x和NMVOCs为主,工业、能源和交通运输为主要贡献源;PM_2.5和PM₁₀主要来自生活民用源和工业源,贡献率前者大于后者。辽宁省污染物（除NH₃外）排放最大,其次为黑龙江省、吉林省和内蒙古东四盟市,冬季排放强度明显高于其他季节。NH₃主要来自农业源,排放峰值发生在5~7月;各清单间排放总量和来源贡献差异明显,EDGAR和PKU清单对NH₃估算差异度为170.3%;SO₂、NO_x、BC和OC的排放差异度均在30%以上。不同活动水平和排放因子的使用是造成清单差异的主要原因。本研究可以掌握东北污染状况,了解清单差异,为本地化清单工作开展提供研究方向,同时也可为模式模拟合理选择清单数据提供参考。     

英国高中地理教材编写特色简析--以《Geography B Evolving Planet》为例

英国是重视地理课程传统的发达国家,拥有丰富的地理教材编写经验。本文以《Evolving Planet》为范本,在阅读与分析的基础上,归纳得出该教材的四大编写特色:设置"以学为中心"的教材栏目,精选多类型优质的地理图像,重视对学生学习方法的引导和注重对学生地理技能的培养。简析该教材的编写特色,以期为未来我国中学地理教材的编写提供启示与借鉴。     

毛乌素沙地锦鸡儿（Caragana）根系微域细菌群落多样性特征

基于16S rRNA高通量基因测序技术,对毛乌素沙地小叶锦鸡儿（Caragana microphylla)、柠条锦鸡儿（Caragana korshinskii）根系微域（即根系、根际土、根区土、灌丛间空白土）间的细菌群落多样性和结构差异性进行表征。本研究对各根系微域间细菌群落的Alpha多样性指数进行了单因素方差分析以及基于OTU水平的PCA分析,探究其在根系微域间Alpha和Beta多样性的层级变化,证实了有关植物根系微域生态位分化的报道,并发现锦鸡儿属植物根系微域间细菌群落的多样性和结构组成随着4个微域类型由外及内呈现出显著的层级差异性（P<0.05）。通过对优势细菌群组的结构组成分析,发现锦鸡儿属植物对特定细菌群组具有显著的向根系内筛选富集的作用（P<0.05）。这种植物通过根系微域对特定细菌群组的逐级筛选富集作用,是导致锦鸡儿属植物灌丛下不同生态位间细菌群落结构和组成发生层级变异的主要原因。