Estimates of vertical land motion along the southwestern coasts of Turkey from coastal altimetry and tide gauge data

The differences between coastal altimetry and sea level time series of tide gauges in between March 1993 and December 2009 are used to estimate the rates of vertical land motion at three tide gauge locations along the southwestern coasts of Turkey. The CTOH/LEGOS along-track coastal altimetry retrieves altimetric sea level anomalies closer to the coast than the standard along-track altimetry products. However, the use of altimetry very close to the coast is not found to improve the results. On the contrary, the gridded and interpolated AVISO merged product exhibits the best agreement with tide gauge data as it provides the smoothest variability both in space and time compared with along track altimetry data. The Antalya gauge to the south (in the Mediterranean Sea) and the Mentes/Izmir gauge to the west (in the Aegean Sea) both show subsidence while the Bodrum tide gauge to the south (in the Aegean Sea) shows no significant vertical land motion. The results are compared and assessed with three independent geophysical vertical land motion estimates like from GPS. The GIA effect in the region is negligible. The VLM estimates from altimetry and tide gauge data are in good agreement both with GPS derived vertical velocity estimates and those inferred from geological and archaeological investigations.     

计算气动弹性在飞行器设计中的研究与应用

近年来,计算气动弹性(CAE)开始作为一个正式术语出现于一些研究文献中,用来描述耦合高精度的计算流体动力学(CFD)与计算结构动力学(CSD)分析气动弹性问题的方法。本文阐述了CAE方法的基本概念、计算流程及其耦合方法,着重分析了CAE求解计算需要解决的关键问题,介绍了CAE方法在飞行器设计中研究应用的发展状况,并展望了其未来的发展方向。     

Analysis of stress-strained state in blanks at multi-pass rotary drawing of cylindrical parts

Some characteristic zones of parts shaped by the multi-pass rotary drawing are presented. Also given are the analytical relations determining deformations in two directions within these zones and recommendations useful to calculate the values of stresses.     

Chromospheric dynamics

This review focuses on dynamics of the solar chromosphere, which serves as a good proxy for understanding processes in stellar chromospheres as well. In the quiet chromosphere it is useful to distinguish between the magnetic network on the boundaries of supergranulation cells, where strong magnetic fields are organized in mainly vertical magnetic flux tubes, and internetwork regions in the cell interior, where magnetic fields are weaker and dynamically less important. Recently, some progress has been made in understanding the physics of the non-magnetic chromosphere. On the other hand, the physical processes that heat the magnetic network have not been fully identified. Is the network heated by wave dissipation and if so, what are their physical characteristics? These and other aspects relating to the dynamics and energy transport mechanisms will be discussed in detail. In addition, some of the outstanding problems in the field such the driving mechanism for spicules and the nature of internetwork magnetic fields will also be highlighted. Furthermore, a critical assessment will be made on the challenges facing theory and the direction for future investigations, particularly in the light of the new space experiments, will be highlighted.     

Cycle slip performance of digitally implemented phase detectors onAWGN channel

Cycle slip performance of digitally implemented phase detectors on additive white Gaussian noise (AWGN) channel is investigated. The performance measure evaluated is the mean cycle slip time of a first-order phase-locked loop. An equivalent phase detector model with state-dependent loop noise is employed. It is shown that this working basis is vital to arrive at correct results. Numerical results for triangular and saw-tooth type phase detectors are reported and compared with those for the multiplier phase detector