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f-3项与投影函数对电离层延迟的影响

依据Chapman正常电离层理论,构造Chapman剖面函数加权投影函数,给出VTEC三角多项式模型,并以武汉站2005年1月1日观测数据进行实例解算,分析电离层延迟f-3项、电离层单层高度、电离层投影函数形式等对电离层延迟的影响.     

水库重力测量检测非牛顿引力的实验数据分析新方法

本文提出水库重力测量检测非牛顿引力的实验数据分析新方法。利用近一天两重力仪的重力差值信号,基于同液面高度变化水体重力信号相等这一具有明显物理意义的准则,建立仪器零漂信号多项式系数矢量的矩阵方程,通过极大似然反演比较严格地计算漂移信号,并从中提取检测信号。实例计算结果表明:(1)当数据充分、漂移多项式阶数取值适当时,该方法完全有效;(2)在现有水库实验的设备和技术条件下,测定万有引力常数G对实验室值的偏离精度可达0.15％,优于矿井实验和先前水库实验的分析结果;若进一步改善水面高度测量,检测精度还可明显提高;(3)Hornberg水库实验重力仪G709在0.4％的精度范围内,未发现G对实验室值的偏离。     

SEA LEVEL RISE OF THE ZHUJIANG RIVER DELTA AND NEOTECTONICS

A linear regression analysis of 28 selected tide-gauge stations of the Zhujiang Estuary shows that there has been a tendency of local sea level rise at a rate of 2.028 mm per year. The origin of the variation is significantly attributed to the local tectonic movement of discrepant fault-block. Based on this, four types of relative local sea level changes are classified. According to calculation, half of the fertile land, or 800 km2 of the delta plain will have been submerged by sea water by about 2040. This will yield a significant influence on the economic construction and human activities.     

A study of extratropical transition and re-intensification of Typhoon Mindulle (2004)

In this study,the fifth-generation Pennsylvania State University-National Center for Atmospheric Research (PSU-NCAR) Mesoscale Model (MM5) is used to simulate Typhoon Mindulle (2004) at high resolution (3-km grid size).The data from measurements show that in the upper atmosphere the existence of an upper jet is important to the transition cyclone.When Mindulle moved to the area of the upper jet entrance,where high-altitude divergence existed, the pumping of the high-altitude divergence would enhance the vertical motion and low-level cyclone convergence. The enhanced vertical motion was confirmed by the simulation results and indicated that the existence of upper divergence enhanced the vertical motion which was favorable for the maintenance of Typhoon Mindulle.The process of extratropical transition (ET) and re-intensification always accompanies the process of cold air invasion. This process enhances the baroclinicity of the atmosphere and the formation of front at high altitudes, which converts baroclinic potential energy into kinetic energy and strengthens the cyclone vortex.The distributions of equivalent potential temperature (θe) and temperature anomalies show that the warm-core of the typhoon at the tropopause aids the re-intensification of the system. As the typhoon reenters the ocean, latent heat flux (LHF) increases in the north and west and the strong reflectivity and vertical motion occur in the east and southeast,and the west.With the re-intensification of the typhoon the wind field evolves from an oval to a circle at the lower atmosphere, the area coverage by high winds increases, and the distribution of the tangential wind shows an asymmetric pattern.     

利用重力多尺度分解资料反演青藏高原东北缘地壳厚度

通过重力异常分解模型,选用小波基函数“bior3.7”,分解得出青藏高原东北缘布格重力异常资料的小波4阶近似成分,利用其主要由莫霍面产生的布格重力异常,以6条人工地震剖面信息做初始控制条件,反演得出青藏高原东北缘的地壳厚度。     

天然地基强迫振动测试与分析

在试验块体分别为明置与埋置情形时,利用激振器对某工程场地天然地基分别进行竖向、水平回转及扭转稳态强迫振动试验。试验结果表明,埋置情形试验的动力特性参数值均大于明置情形试验相应值;同种试验情形下,地基第一振型共振频率竖向最大,水平回转向其次,扭转向最小;土的参振质量均远大于基础本身质量。     

ENVIRONMENTAL CHANGE AND ITS IMPACTS ON HUMAN SETTLF, MENT IN THE CHANGJIANG RIVER DELTA IN NEOLITHIC AGE

Dating data, altitude of Neolithic sites, climatic changes from sedimentary records and previous research results were collected and analyzed to detect possible connections between climatic changes and human activities in the Changjiang River Delta in the Neolithic Age. The results indicated that hydrological changes greatly impacted the human activities in the study region. Low-lying geomorphology made the floods and sea level changes become the important factors affecting human activities, especially the altitude change of human settlements. People usually moved to higher places during the periods characterized by high sea level and frequent floods to escape the negative influences from water body expansion, which resulted in cultural hiatus in certain profiles. However, some higher-altitude settlements were not the results of climatic changes but the results of social factors, such as religious ceremony and social status. Therefore, further research will be necessary for the degree and types of impacts of climatic changes on human activities in the study area at that time.     

Complete nuclear ribosomal DNA sequence amplification and molecular analyses of <Emphasis Type="Italic">Bangia</Emphasis> (Bangiales,Rhodophyta) from China

Filamentous Bangia, which are distributed extensively throughout the world, have simple and similar morphological characteristics. Scientists can classify these organisms using molecular markers in combination with morphology. We successfully sequenced the complete nuclear ribosomal DNA, approximately 13 kb in length, from a marine Bangia population. We further analyzed the small subunit ribosomal DNA gene (nrSSU) and the internal transcribed spacer (ITS) sequence regions along with nine other marine, and two freshwater Bangia samples from China. Pairwise distances of the nrSSU and 5.8S ribosomal DNA gene sequences show the marine samples grouping together with low divergences (00.003; 0–0.006, respectively) from each other, but high divergences (0.123–0.126; 0.198, respectively) from freshwater samples. An exception is the marine sample collected from Weihai, which shows high divergence from both other marine samples (0.063–0.065; 0.129, respectively) and the freshwater samples (0.097; 0.120, respectively). A maximum likelihood phylogenetic tree based on a combined SSU-ITS dataset with maximum likelihood method shows the samples divided into three clades, with the two marine sample clades containing Bangia spp. from North America, Europe, Asia, and Australia; and one freshwater clade, containing Bangia atropurpurea from North America and China.     

基于Arc Engine的冻土极值深度查询系统的二次开发和应用

利用国家一、二等水准测量规范提供的冻土极值深度基础数据,基于Arc Engine+.net二次开发平台,设计冻土极值深度查询系统。在此基础上,结合晋冀蒙形变监测网阳红线、砂石线等15条水准路线点之记数据,对查询结果进行精度验证,误差均值为+1.16 cm,方差为1.70 cm2,满足埋石工作的精度要求。