北京市区春季燃烧源大气颗粒物的污染水平和影响因素

以大气中PM2.5和PM10为研究对象,于2005-03-13—25共7天的时间内,在中国地质大学(北京)测试楼顶、首钢焦化厂和首钢东门设立3个采样点进行采样监测。结果表明:PM2.5和PM10质量浓度的日变化呈现一定规律性,在不同时段PM2.5和PM10的质量浓度不尽相同,且变化较大,在特定时刻出现峰值,主要受污染源排放和气象因素的控制;PM2.5和PM10质量浓度随气温的升高而降低,这与高温有利于颗粒物扩散、低温容易形成逆温层有关;在一定的相对湿度范围内(以大气中水汽不发生重力沉降为界限),PM2.5和PM10质量浓度与相对湿度呈正相关关系;而当发生降水时,由于水滴的冲刷和附带作用,PM2.5和PM10质量浓度降低;PM2.5和PM10质量浓度与风级呈明显的负相关关系。通过北京市与国内8个省会城市的PM2.5和PM10质量浓度的对比,发现北京市PM2.5和PM10污染比较严重,PM2.5和PM10质量浓度分别超过了1996年中国制定的PM10排放标准和1997年美国EPA制定的PM2.5排放标准。     

MRI分割的几何活动轮廓模型的半隐式AOS迭代方法

几何活动轮廓模型以其计算稳定等优点，被广泛用于图像分割。给出一种基于AOS(additive operator splitting)算法的快速活动轮廓模型，将AOS方法与几何活动轮廓模型相结合构造一种半隐式迭代模型，它对迭代步长没有限制，从而可以选择较大的迭代步长，提高了模型的时间效率，并使用区域信息构造系数矩阵，使模型具有全局性。对MR(magnetic resonance)图像分割的实验表明，该模型可以得到较好的分割结果，同时时间效率也有大幅提高，方便了实时应用。     

基于小波统计特性的遥感图像像素与特征联合最优融合方法

遥感影像的IHS融合方法由于匹配误差导致光谱畸变和退化,而小波变换在变换域具有良好的分频特性,小波系数的统计特性反映了遥感影像的边缘、线和区域等显著特征。提出了基于小波统计特性的遥感影像的像素和特征联合最优融合方法,在IHS空间,对强度分量I的高频部分利用多分辨率小波融合方法进行影像的高频细节特征融合,低频部分选取光谱信息和空间分辨率评价指标作为融合权系数求优指标,进行像素级最优融合,实验结果证明了该方法的有效性。     

Predicting grain protein content of winter wheat using remote sensing data based on nitrogen status and water stress

Advanced site-specific knowledge of grain protein content of winter wheat from remote sensing data would provide opportunities to manage grain harvest differently, and to maximize output by adjusting input in fields. In this study, remote sensing data were utilized to predict grain protein content. Firstly, the leaf nitrogen content at winter wheat anthesis stage was proved to be significantly correlated with grain protein content (R² = 0.36), and spectral indices significantly correlated to leaf nitrogen content at anthesis stage were potential indicators for grain protein content. The vegetation index, VI_green, derived from the canopy spectral reflectance at green and red bands, was significantly correlated to the leaf nitrogen content at anthesis stage, and also highly significantly correlated to the final grain protein content (R² = 0.46). Secondly, the external conditions, such as irrigation, fertilization and temperature, had important influence on grain quality. Water stress at grain filling stage can increase grain protein content, and leaf water content is closely related to irrigation levels, therefore, the spectral indices correlated to leaf water content can be potential indicators for grain protein content. The spectral reflectance of TM channel 5 derived from canopy spectra or image data at grain filling stage was all significantly correlated to grain protein content (R² = 0.31 and 0.37, respectively). Finally, not only this study proved the feasibility of using remote sensing data to predict grain protein content, but it also provided a tentative prediction of the grain protein content in Beijing area using the reflectance image of TM channel 5.     

福建福安下白石特大桥海上岩土勘察方法

下白石特大桥是同江至三亚国道主干线福鼎至宁德高速公路建设中的一项控制性工程 ,是交通部指定的三阶段设计工程 ,桥长 110 5 m,主跨采用 2× 2 6 0 m预应力混凝土连续钢构。桥位位于白马河入海口处 ,工程地质、水文地质条件复杂 ,通过采用地表大面积的综合地质调查、海上地震映像物探以及海上钻探、原位测试、岩土测试等一系列行之有效的岩土勘察方法 ,确保了岩土工程勘察质量 ,其结果切实可行 ,为后期施工单位提供科学依据。     

中下扬子区二叠系露头层序地层研究

按新近国际年代地层划分方案（ICS，2000），下扬子区二叠纪地层自下向上分为3统，9阶和相对应的华南传统6阶划分。二叠系从阿瑟尔阶至长兴阶（44Ma)共划分出14个三级层序，每个三级层序平均时限约为3.14Ma，其中“紫松阶”）相当阿瑟尔＋2／3萨克马尔阶）1个（船山组中上部）、“隆林阶、（相当1／3萨克马尔阶＋阿丁斯克阶）2个（分别对应船山组上部和梁山组或镇江组）、“栖霞阶”（相当库班甘德阶＋1／3罗德阶）3个（栖霞组），“茅口阶”（相当于2／3罗德阶＋沃德阶＋卡皮丹阶）4个（孤峰组，茅口组，堰桥组，银屏组和武穴组），吴家坪阶2个（龙潭组或吴家坪组），长兴阶2个（长兴组或大隆组）；共归并为4个层序组（sequence set)。     

Probabilistic analysis of peak response of MDOF systems with uncertain PSD function

The use of uniform hazard spectra which have the same probability of exceedance at different frequencies has been proposed for the future version of the National Building Code of Canada. Commonly used combination rules to estimate the peak responses of multi‐degree‐of‐freedom (MDOF) systems are the square root of sum of squares rule and the complete quadratic combination rule. However, the probability that the peak response of a MDOF system exceeds the one estimated by using these rules with the peak modal responses from the uniform hazard spectra cannot be inferred directly. The assessment of the probability of exceedance of the peak response of MDOF systems is presented by considering that the uncertainty in seismic excitation due to all potential earthquakes can be lumped in the power spectral density function of the ground acceleration with uncertain model parameters. This probability is evaluated based on the random vibration of linear systems and the first‐order reliability method. It is found that the under‐ or over‐estimations are less than about 5 or 10% if the modal contributions are not within 10–90% of, or not within 20–80% of, the absolute sum of the effective modal peak responses, respectively. Otherwise, severe under‐ or over‐estimation could result. Copyright © 2002 John Wiley & Sons, Ltd.     

运用层序不对称性分析海平面变化特征

目前研究海平面变化的方法尚不能精确确定海平面变化，对记录海平面变化的沉积体或层序物质组成及结构特点的研究尚显薄弱。在分析层序不对称性与海平面变化的关系基础，提出层序不对称系数S0，认为海平面的升降变化对浅水沉积区影响显著，其结果必然造成层序S0的增加；海平面的升降变化对沉水沉积区影响不大，层序S0较为恒定。对进行详细研究中扬子区S0分布特点，运用S0曲线计算了中扬子区海平面变化特点，并与其他方法进行对比，认为可以用S0判断水体相对深浅，分析海平面变化。     

鄂尔多斯盆地上古生界高分辨率层序地层分析

按基准面旋回原理，将鄂尔多斯盆地上古生界本溪组（C2b)、太原组（P1t）、山西组(P1s)和下石盒子组（P1xs)划分为3个超长期、8个长期、19个中期和62个短期旋回层序：较为详细地介绍了各级别层序的结构类型、叠加样式和沉积演化序列；建立以长期旋回层序为年代地层框架，中期旋回层序为等时地层对比单元的层序的地层格架；并讨论高分辨率层序地层与天然气藏的关系。     

Cathodoluminescence of authigenic albite

Authigenic albites in carbonate rocks typically grow in a high-grade diagenetic to low-grade metamorphic environment and often show Roc-Tourné-twinning sensu Füchtbauer. Based on an investigation of four Middle to South European occurrences, they show Mn²⁺- and Fe³⁺-activated cathodoluminescence (CL), as revealed by combined high resolution spectroscopy of cathodoluminescence emission (HRS-CL), electron paramagnetic resonance (EPR), and proton-induced X-ray emission (μPIXE).