IMMIGRATION, GEOGRAPHIC DISTRIBUTION AND SOCIAL ECONOMIC STATUS OF AMERICAN CHINESE

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A GPS-slaved time synchronization system for hybrid navigation

For multisensor integration, a primary prerequisite is time synchronization. Methods that have been used in many operational systems are either too expensive, or have inconvenient features, that make them inappropriate for research purposes. In this paper, the system design of a cost effective synchronization system (CESS) is described. Tests show that a synchronization accuracy of 0.4 ms can be achieved using this system. A land trial of GPS/INS integration verified that the CESS is accurate enough for most low-cost sensor integration applications. However, a more accurate synchronization can be achieved by minor modifications to the CESS. This system provides an ideal platform for researchers to build their own integrated multisensor systems.     

几种消暖云（雾）催化剂性能的实验研究

本文选取了十一种吸湿性物质,对它们的吸湿特性进行了实验研究,对其中一些吸湿性能较好的催化剂开展了云室消雾试验,结果表明,这些物质的吸湿能力及其随相对湿度变化的分布有较大的区别,其饱和状态下的平衡增长率也有较大差异,水泥类物质中,矿渣水泥及普通４２５＾＃Ｋ水泥的吸湿特性与氯化钠类似,氯化钠、氯化铵及矿潭水泥的云室消雾效果较好,但其作用机理可能有所不同。     

西北地区地震综合预报探讨

本文初步总结了西北地区近十几年来地震综合预报的探索与进展。结果表明,在中长期趋势预测方面,对多数5级以上破坏性地震已具有测震学监测基础,综合预测结果基本上通过了统计检验;在短临预测方面仅对乌鲁木齐地区和兰州、银川、西安和武都范围以内发生的6 1/2级以上地震具有初步的监测基础。由19个震例获得以测震学资料为主的中长期趋势异常共73项,以地下水位、水氧、地电和地磁资料为主的短临异常共59项。本文概述了有关异常的特征和综合预报思路,讨论了有关问题和动向。     

Estimation of the sensible heat flux of a semi-arid area using surface radiative temperature measurements

In the framework of an international field program for the study of semi-arid areas, observations were done in the region called La Crau in southern France. In this paper, the use of the surface radiative temperature for the determination of the sensible heat flux is addressed. We found that, once proper values of the roughness length of momentum (z ₀) and heat (z ₀h) are set, the sensible heat flux can be reliably predicted with a one-layer resistance model using standard observations of wind speed and air temperature, together with the surface temperature. The latter quantity has to be known with a precision better than ±2°C. From our observations, the value of the parameterB ^–1k ^–1 In (z ₀ z ₀h) was found to be 9.2, which falls between values quoted by Brutsaert (1982) for grass and bluff bodies.     

Alluvial geoarchaeology of a Middle Archaic Mound complex in the lower Mississippi Valley,U.S.A.

The Nolan site (16MA201), ¹⁴C dated 5200–4800 cal yr B.P. and located in the Tensas Basin of northeastern Louisiana, is the only recorded Middle Archaic mound site in the alluvial valley of the Mississippi River. Alluvial deposition has buried the Nolan site under 3–4 m of Holocene sediment, prohibiting traditional excavation of the site. Because data are unattainable by other means, soil coring and subsequent stratigraphic and sedimentological analyses permit reconstruction of the natural and cultural depositional history of the Nolan site. The sedimentary characteristics of basal deposits within cores suggest the presence of an Arkansas River paleochannel immediately adjacent to the site. Chronostratigraphic data show this channel was no longer active by ca. 5200 cal yr B.P. Contrary to existing models, the Arkansas River Meander Belt 4 and the Mississippi River Meander Belt 4 are not the same age. Microartifact and losson‐ignition analyses of sediment identify natural versus cultural strata and permit the identification of artificial constructions—including four earthen mounds and one earthen ridge—at the Nolan site. Overbank sediments attributed to a mapped Mississippi River Stage 4 meander belt are dated ca. 4800–3800 cal yr B.P. This age is considerably younger than previous estimates and demonstrates the existing chronological models for Mississippi River meander belts must be carefully assessed. Core analyses also reveal flood‐related crevasse splays deposited throughout the Tensas Basin after the occupation of the Nolan site. These deposits serve as relative chronological indicators and aid in stratigraphic assessments of the Nolan site. Reconstruction of the earthworks and their stratigraphic context reveals one of the largest and earliest Middle Archaic mound sites in North America. © 2006 Wiley Periodicals, Inc.     

四川省遂宁市城市湿地公园规划建设初探

建设城市湿地公园是落实国家湿地分级分类保护管理策略的一项具体措施,也是当前形势下维护和扩大湿地保护面积行之有效的途径之一。遂宁拥有丰富的城市湿地资源,具有建设湿地公园得天独厚的条件,本文从多个方面对遂宁建设城市湿地公园的可行性进行了分析,希望对遂宁的湿地保护乃至整个西部的湿地资源保护规划起到指导作用。     

The Maximum Effective Moment Criterion （MEMC） and Its Implications in Structural Geology

1 Introduction A high-level generalization of structures in the earth crust has been given by Ramsay (1980): low-angle thrusts in the brittle upper crust and high-angle reverse shear zones in the ductile middle-lower crust are formed in contractional regimes; high-angle normal faults in the brittle upper crust and low-angle normal shear zones in the ductile middle- lower crust are formed in extensional regimes. The formation of low-angle thrusts and high-angle normal faults in brittle domains …     

磷灰石中磁黄铁矿出溶结构的发现

中国东部苏鲁地区(江苏赣榆)出露大理岩-榴辉岩块体,其菱镁矿大理岩中保存的白云石分解结构表明地壳物质俯冲深度达到-200公里。在与该大理岩共生的榴辉岩中,我们发现了磷灰石的磁黄铁矿出溶结构。磷灰石是该榴辉岩的主要副矿物,其自形程度较高,与石榴石共生。样品中几乎所有磷灰石均发育出溶结构,至少存在两组相互垂直的出溶棒,它们各自严格沿同一个方向分布。出溶棒形状规则,宽度相近(<1μm),但长度变化大(5-50μm)。利用高分辨能谱仪测定其能谱,结果表明,出溶棒主要由Fe和S两种元素组成,但不能准确地确定其Fe/S比值。我们把这种出溶棒初步确定为磁黄铁矿(Fe1-xS)。磷灰石由于含大量稀土元素和挥发性组分如OH、F、Cl等以及我们所观察到的S,它的深循环因此可能对地球的水、硫以及其它挥发性组分的全球平衡具有重要影响。本文报道的磷灰石中磁黄铁矿出溶结构为深入探讨这个基本科学问题提供了一个新的突破口。