Monitoring regional sea ice of the Bohai Sea by SSM/I scattering index

ＭｏｎｉｔｏｒｉｎｇｒｅｇｉｏｎａｌｓｅａｉｃｅｏｆｔｈｅＢｏｈａｉＳｅａｂｙＳＳＭ／ＩｓｃａｔｔｅｒｉｎｇｉｎｄｅｘＪｉｎＹａｑｉｕ（ＲｅｃｅｉｖｅｄＪａｎｕａｒｙ６,１９９７;ａｃｃｅｐｔｅｄＭａｒｃｈ３０,１９９７）Ａｂｓｔｒａｃｔ──ＳＳＭ／...     

溢油乳化过程C波段微波散射特性实验研究

本文基于水槽溢油观测实验,研究溢油乳化过程中表面散射特性的变化。利用全极化C波段微波散射计和矢量网络分析仪等测量设备对易发生乳化反应沥青含量小于3%的原油（A型油）、油田中开采出的新鲜原油（B型油）和经过脱水去杂质处理的工业原油（C型油）进行观测。文中详细分析了在C波段微波下乳化油膜与平静水面的后向散射差异,以及油膜乳化过程对后向散射的影响,结果显示在低风速、无浪的条件下（最大波高低于3mm）,原油的乳化反应可通过表面粗糙度和自身介电常数的变化来调制雷达后向散射,并且这两种方式中表面粗糙度的影响占主导地位。对比B型和C型原油在乳化状态和未乳化状态下的表面后向散射,结果显示在各状态下B型油膜表面后向散射均大于C型油,且在VV、HH、HV/VH极化方式下两者后向散射平均差异分别为2.19 dB、2.63 dB、2.21 dB,在20%油膜含水率的乳化状态下差异较未乳化状态时小,平均差异分别为0.98 dB、1.49 dB、1.5 dB,结果表明不同类型油种间由于成分和油膜属性的不同会在一定程度上导致油膜表面粗糙度存在差异,影响油膜表面后向散射。     

The carboniferous lithostratigraphy of Southeast County Limerick,Ireland, and the origin of the shannon trough

The Carboniferous succession in southeast County Limerick, on the southeastern margin of the Shannon Trough, is Courceyan to mid-Namurian in age and over 1900 m thick. The lithostratigraphy is described in detail. Its most important aspect is the presence of two thick volcanic sequences, a Chadian one of the alkali basalt to trachyte suite and one of Asbian age dominated by limburgites and ankaramites. The associated Dinantian carbonates are of shelf or ramp facies throughout, and no fundamental division into shelf and basin facies occurs as in the Dublin and Craven Basins in early Viséan times. Rapid differential subsidence between this area and the Shannon Estuary began during deposition of the late Courceyan to early Chadian Waulsortian facies but was less marked in the remaining Viséan when much of the volcanic topography was preserved by rapid basinal subsidence. There was basinal inversion in the late Dinantian to lower Namurian, followed by renewed subsidence in mid-Namurian times. This contrasts with the continuous rapid subsidence of the area further west on the Shannon Estuary. This behaviour, together with a comparison of that of nearby Carboniferous basins such as the Dublin, South Munster, and Craven Basins, which lack substantial volcanic sequences, suggests an origin in a transtensional regime rather than one of simple crustal stretching.     

洱源-江川宽角地震剖面的地壳反射特征

通过对洱源-江川宽角反射地震资料的叠前偏移处理成像,得到了一个类似于近垂直入射多道地震数据的记录剖面.反射剖面图像与地壳速度结构共同揭示出地壳厚度由剖面西北端(约45 km)向东南端(约40 km)减薄.在洱源-楚雄西北附近深度约10 km处存在一组向东南倾斜的强反射震相,其东南约50 km处存在向西北倾斜的强射震相.易门断裂两侧地壳反射属性具有明显的差异,易门断裂之西北方向深度25～40 km处,中下地壳内存在两组强振幅,向东南方向上倾的地震反射同相轴,并被楚雄-建水断裂后期所错断,易门断裂之东南方向上,地壳内反射较为均一,未见特别明显的强间断面反射信息,这个反射结构被解释为印度板块东向俯冲与藏东缘地壳物质东向逃逸综合作用导致下地壳增厚和厚地壳变形的结果.     

An interconnect width and spacing optimization model considering scattering effect

As the feature size of the CMOS integrated circuit continues to shrink, the more and more serious scattering effect has a serious impact on interconnection performance, such as delay and bandwidth. Based on the impact of the scattering effect on latency and bandwidth, this paper first presents the quality-factor model which optimises latency and bandwidth effectively with the consideration of the scattering effect. Then we obtain the analytical model of line width and spacing with application of curve-fitting method. The proposed model has been verified and compared based on the nano-scale CMOS technology. This optimisation model algorithm is simple and can be applied to the interconnection system optimal design of nano-scale integrated circuits.     

Improvement in the calculation of anti-Stokes energy transfer and experimental justification based on Er0.01YbxY1 - 0.01 - xVO4 crystal

The improvement on the calculation of anti-Stokes energy transfer rate is studied in the present work. The additional proportion coefficient between Stokes and anti-Stokes light intensities of quantum Raman scattering theory as compared with the classical Raman theory is introduced to successfully describe the anti-Stokes energy transfer. The theoretical formula for the improvement on the calculation of anti-Stokes energy transfer rate is derived for the first time in this study. The correctness of introducing coefficient exp{ΔE / kT} from well-known Raman scatter theory is demonstrated also. Moreover, the experimental lifetime measurement in Er_0.01Yb_xY_{1 - 0.01 - x}VO₄ crystal is performed to justify the validity of our important improvement in the original phonon-assisted energy transfer theory for the first time.     

Brillouin scattering study on elastic and piezoelectric properties of laser irradiated ZnO single crystals

Brillouin light scattering technique can be successfully used to determine the whole set of elastic and piezoelectric constants of a ZnO single crystal irradiated by different laser energy densities, into a micron range (radiation layer thickness). It is found that the scattering intensity, the linewidth and the Brillouin scattering shift of acoustic phonons are all strongly dependent on laser energy density. Based on the sound propagation equations and these results, the directional dependences of the compressional and shear moduli of the irradiated ZnO sample in the (001) plane are investigated. It is found that under an appropriate laser condition, 248 nm KrF excimer laser irradiation can significantly improve the surface quality and increase the elastic properties of ZnO single crystal. This procedure has potential applications in the fabrication of ZnO-based surface acoustic wave and optic-electronic devices.     

华北克拉通南部太古宙大陆地壳的生长和演化

太古宙约占地球已有演化历史的三分之一强,这一时期涉及到大陆地壳起源、陆壳的巨量生长和稳定以及板块构造作用的启动、建立等诸多最根本的全球性重大地质事件.太古宙岩石在华北克拉通南部的涑水、登封、太华、霍邱和五河等杂岩中广泛出露,这为解析上述重大科学问题提供难得的素材.近十年来,在华北克拉通南部古生代-中生代火山岩或早前寒武...     

Time domain method for calculating free field motion of a layered half-space subjected to obliquely incident body waves

In numerical simulation of wave scattering under oblique incident body waves using the finite element method, the free field motion at the incident lateral boundary induced by the background layered half-space complicates the computational area. In order to replace the complex frequency domain method, a time-domain method to calculate the free field motion of a layered half-space subjected to oblique incident body waves is developed in this paper. The new method decouples the equations of motion used in the finite element method and offers an interpolation formula of the free field motion. This formula is based on the fact that the apparent horizontal velocity of the free field motion is constant and can be calculated exactly. Both the theoretical analysis and numerical results demonstrate that the proposed method offers a high degree of accuracy.     

A review of numerical experiments on seismic wave scattering

This paper reviews applications of the finite-difference and finite-element methods to the study of seismic wave scattering in both simple and complex velocity models. These numerical simulations have improved our understanding of seismic scattering in portions of the earth where there is significant lateral heterogeneity, such as the crust. The methods propagate complete seismic wavefields through highly complex media and include multiply scattered waves and converted phases (e.g.,P toSV, SV toP, body wave to surface wave). The numerical methods have been especially useful in cases of moderate and strong scattering in complex media where multiple scattering becomes important. Progress has been made with numerical methods in understanding how near-surface, low-velocity basin structures scatter surface waves and vertically-incident body waves. The numerical methods have proven useful in evaluating scattering of surface waves and body waves from topography of both the free surface and interfaces buried at depth. Numerical studies have demonstrated the importance of conversions from body waves to surface waves (andvice versa) when lateral heterogeneities and topographic relief are present in the uppermost crust. Recently, several investigations have applied numerical methods to study seismic wave propagation in velocity models which vary randomly in space. This stochastic approach seeks to understand the effects of small-scale complexity in the earth which cannot be resolved deterministically. These experiments have quantified the relationships between the statistical properties of the random heterogeneity and the measurable properties of high-frequency (1 Hz) seismograms. These simulations have been applied to the study of many features observed in actual high-frequency seismic waves, including: the amplitude and time decay of seismic coda, the apparent attenuation from scattering, the dispersion of waveforms, and the travel time and waveform variations across arrays of receivers.