水文时间系列周期分析方法探讨

以分析广东省降水周期变化规律为例，探讨了最大熵谱方法在提取水文时间系列的主次周期上以及小波变换方法在分析水文时间系列的多时间尺度演变规律上的应用。由计算结果分析得到广东省降水过程主要存在的周期特性和旱涝变化趋势，为广东省降水趋势预测提供了重要信息。     

Source mechanism and source parameters of May 28, 1998 earthquake,Egypt

On May 28, 1998, a moderate size earthquake of mb 5.5 occurred offshore the northwestern part of Egypt (latitude 31.45°N and longitude 27.64°E). It was widely felt in the northern part of Egypt. Being the largest well-recorded event in the area for which seismic data from the global digital network are available, it provides an excellent opportunity to study the tectonic process and present day stress field occurring along the offshore Egyptian coast. The source parameters of this event are determined using three different techniques: modeling of surface wave spectral amplitudes, regional waveform inversion, and teleseismic body waveform inversion. The results show a high-angle reverse fault mechanism generally trending NNW–SSE. The P-axis trends ENE–WSW consistently with the prevailed compression stress along the southeastern Hellenic arc and southwestern part of the Cyprean arc. This unexpected mechanism is most probably related to a positive inversion of the NW trending offshore normal faults and confirms an extension of the back thrusting effects towards the African margin. The estimated focal depth ranges from 22 to 25 km, indicating a lower crustal origin earthquake owing to deep-seated tectonics. The source time function indicates a single source with rise time and total rupture duration of 2 and 5 s, respectively. The seismic moment (M _o) and the moment magnitude (M _w) determined by the three techniques are 1.03 × 10¹⁷ Nm, 5.28; 1.24 × 10¹⁷ Nm, 5.33; and 1.68 × 10¹⁷ Nm, 5.42; respectively. The calculated fault radius, stress drop, and the average dislocation assuming a circular fault model are 7.2 km, 0.63 Mpa, and 0.11 m, respectively.     

Acceleration response modification factors for nonstructural components attached to inelastic moment‐resisting frame structures

A statistical analysis of the peak acceleration demands for nonstructural components (NSCs) supported on a variety of stiff and flexible inelastic regular moment‐resisting frame structures with periods from 0.3 to 3.0 s exposed to 40 far‐field ground motions is presented. Peak component acceleration (PCA) demands were quantified based on the floor response spectrum (FRS) method without considering dynamic interaction effects. This study evaluated the main factors that influence the amplification or decrease of FRS values caused by inelasticity in the primary structure in three distinct spectral regions namely long‐period, fundamental‐period, and short‐period region. The amplification or decrease of peak elastic acceleration demands depends on the location of the NSC in the supporting structure, periods of the component and building, damping ratio of the component, and level of inelasticity of the supporting structure. While FRS values at the initial modal periods of the supporting structure are reduced due to inelastic action in the primary structure, the region between the modal periods experiences an increase in PCA demands. A parameter denoted as acceleration response modification factor (R_acc) was proposed to quantify this reduction/increase in PCA demands. Copyright © 2007 John Wiley & Sons, Ltd.     

任意多边形间方向关系的计算及其可确定问题

提出了一种符合空间认知规律的栅格化处理的任意多边形间方向关系的计算方法，该方法计算结果与人眼的判断结果非常接近，在此基础上讨论了多边形间方向关系的可确定问题，并提出了一种基于8方向隶属零值个数的两个多边形方向关系可确定程度的判定方法。     

山东蓝宝石的呈色机制及改色试验

利用穆斯堡尔谱分析结果以及前人光谱分析等资料，从铁离子的价态入手，重新确立了山东蓝宝石的呈色机制，确定出致蓝因素与致黑因素。认为Fe^2 与Ti^4 对可见光565nm的吸收是使蓝宝石产生美丽蓝色调的原因，而Fe^3 对可见光442nm的吸收是使蓝宝石呈黑色的原因，并在此基础上进行了以消除Fe^3 、保障并增加Fe^2 和Ti^4 为宗旨的改色实验，取得了较好的效果。     

非开挖穿河铺设光缆管道工程的施工技术

穿越向荡巷河铺设光缆管道工程,采用先进的非开挖导向铺管技术,成功地穿越了110m宽的河流,铺道最大埋深14m。此项工程特点:一次性铺管距离长,深度大,管线多,工期短,精度高。     

REMOTE SENSING OF THE SEASONAL VARIATION IN COLUMN ABUNDANCE OF ATMOSPHERIC CH4*

Infrared solar spectra on clear days were measured automatically by an infrared solar spectrometer(ISS) with 0.4 cm^-1 resolution developed by us.A line-by line(LBL) computation method was used to calculate theoretical atmospheric absorption.In the wavelength range of 3.410-3.438 μm.the absorption is mainly due to atmospheric methane and water vapor.Columnatmospheric methane was retrieved from the recorded infrared solar spectra.The seasonal variation of column atmospheric methane in Hefei has been obtained from the measuremental data of nearly 18 months since the April of 1997.and found that it is similar to that of background data.The instruments.principles of measurement and some of results were introduced,and the results are also discussed briefly in the paper.     

A study of design spectra based on attenuation relationship of ground motion

In recent years, more and more studies are focused on the performance in seismic design instead of the strength of structures. People have realized that the structure deformation (displacement) can describe the damage more properly and directly than the strength (force). The displacement design spectra need to be constructed within more wide range of the period and the damping for the displacement-based seismic design.     

探地雷达天线方向特性探讨

利用电磁波的传播特点,对元天线、对称振子及其天线阵辐射电磁波的方向性做进一步的探讨,并分析各因素对其辐射方向性的影响。     

Calculation of the UV Absorption Spectra of As(III) Oxo- and Thio- Acids and Anions in Aqueous Solution and of PF3 in the Gas-phase

Changes in the UV spectra of As(OH)₃ solutions with variations in pH and temperature have recently been used to determine the temperature dependence of the pK_a of the acid. In previous studies I used quantum mechanical techniques to study changes in structure and vibrational spectra as a function of pH for arsenites and thioarsenites. I previously calculated UV spectra for ``molecular' minerals, like realgar As₄S₄. Here I use a number of different quantum mechanical methods, both Hartree-Fock and density functional theory based, to calculate the UV spectra for both a related simple well-characterized gas-phase molecule PF₃ and for As(OH)₃ and As(SH)₃ and their conjugate anions and some neutral and anionic oligomers in aqueous solution. For the monomeric species small numbers of water molecules have been explicitly included, in a supermolecule or microsolvation approach. I find that UV absorption energies accurate to a few tenths of an eV can be obtained both for gas- phase PF₃ and for neutral arsenious acid in aqueous solution, for which the UV absorption maximum is calculated to occur around 6.5 eV, consistent with experiment. Accurate calculation of the UV energies for arsenite anions in aqueous solution is much more difficult, since basis set size and solvation effects are considerably larger than for the neutral molecules, but fairly reliable results can still be obtained. Deprotonation is found to reduce the lowest calculated UV transition energy by about half an eV. Oligomerization also reduces the lowest calculated UV energy by at least half an eV. Replacement of one or all the –OH groups by –SH groups reduces the lowest calculated UV energies by about 2 eV. UV excitation energies have been calculated for oligomeric species as large as As₃E₃(EH)₃ and As₄E₆, where E = O, S, and may be useful for identifying such species in solution.