3D scattering of obliquely incident plane SV waves by an alluvial valley embedded in a fluid-saturated, poroelastic layered half-space

The indirect boundary element method is used to study the 3D dynamic response of an infinitely long alluvial valley embedded in a saturated layered half-space for obli- quely incident SV waves. A wave-number transform is first applied along the valley＇s axis to reduce a 3D problem to a 2D plane strain problem. The problem is then solved in the section perpendicular to the axis of the valley. Finally, the 3D dynamic responses of the valley are obtained by an inverse wave-number transform. The validity of the method is con- firmed by comparison with relevant results. The differences between the responses around the valley embedded in dry and in saturated poroelastic medium are studied, and the effects of drainage conditions, porosity, soil layer stiffness, and soil layer thickness on the dynamic response are dis- cussed in detail resulting in some conclusions.

Generalized 3D Scattering Channel Model with MIMO Antenna Systems

In this paper, a generalized three-dimensional(3D) scattering channel model for macrocellular land mobile environments is considered. This model simultaneously describes angular arrival of multi-path signals in the azimuth and elevation planes in an environment where uniformly distributed scatterers are assumed to be present in hemispheroids around the base station(BS) and mobile station(MS). Using this channel model, we first derive the closed-form expression for the joint and marginal probability density functions of the angle-of-arrival and time-of-arrival measured at the BS and the MS corresponding to the azimuth and elevation angles. Next, we derive an expression for the Doppler spectral distribution caused by motion of the MSs. Furthermore, we analyze the performance of multiple-input multiple-output antenna systems numerically. The results show that the proposed 3D scattering channel model performs better than previously proposed two-dimensional(2D) models for indoor and outdoor environments. We compare the results with previous scattering channel models and measurement results to validate the generalizability of our model.

Analysis of the joint detection capability of the SMILE satellite and EISCAT-3D radar

The Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)satellite is a small magnetosphere–ionosphere link explorer developed cooperatively between China and Europe.It pioneers the use of X-ray imaging technology to perform large-scale imaging of the Earth’s magnetosheath and polar cusp regions.It uses a high-precision ultraviolet imager to image the overall configuration of the aurora and monitor changes in the source of solar wind in real time,using in situ detection instruments to improve human understanding of the relationship between solar activity and changes in the Earth’s magnetic field.The SMILE satellite is scheduled to launch in 2025.The European Incoherent Scatter Sciences Association(EISCAT)-3D radar is a new generation of European incoherent scatter radar constructed by EISCAT and is the most advanced ground-based ionospheric experimental device in the high-latitude polar region.It has multibeam and multidirectional quasi-real-time three-dimensional(3D)imaging capabilities,continuous monitoring and operation capabilities,and multiple-baseline interferometry capabilities.Joint detection by the SMILE satellite and the EISCAT-3D radar is of great significance for revealing the coupling process of the solar wind–magnetosphere–ionosphere.Therefore,we performed an analysis of the joint detection capability of the SMILE satellite and EISCAT-3D,analyzed the period during which the two can perform joint detection,and defined the key scientific problems that can be solved by joint detection.In addition,we developed Web-based software to search for and visualize the joint detection period of the SMILE satellite and EISCAT-3D radar,which lays the foundation for subsequent joint detection experiments and scientific research.

High-Frequency Guided Wave Scattering by a Partly Through-Thickness Hole Based on 3D Theory

We present a theoretical investigation of the scattering of high frequency S0 Lamb mode from a circular blind hole defect in a plate based on the 3D theory. The SO wave is incident at the frequency above the A1 mode cut-off frequency, in which the popular approximate plate theories are inapplicable. Due to the non-symmetric blind hole defect, the scattered fields will contain higher order converted modes in addition to the fundamental SO and AO modes. The far-field scattering amplitudes of various propagating Lamb modes for different hole sizes are inspected. The results are compared with those of lower frequencies and some different phenomena are found. Two-dimensional Fourier transform （2DFT） results of transient scattered Lamb and SH wave signals agree well with the analytical dispersion curves, which check the validity of the solutions from another point of view.

A Photolithography Process Design for 5 nm Logic Process Flow

With the introduction of EUV lithography,the photolithographic process in 5 nm logic process can be simplified to use mostly single exposure method.In a typical 5 nm logic process,the contact-poly pitch(CPP)is 44-50 nm,the minimum metal pitch(MPP)is around 30-32 nm.And the overlay budget is estimated to be 2.5 nm(on product overlay).Although the optical resolution of a 0.33NA exposure tool(such as ASML NXE3400)can reach below 32 nm pitch,stochastics in the EUV absorption in photoresists has limited its application to smaller pitches.For the CPP mentioned above,one can use 193 nm immersion lithography with Self-Aligned Double Patterning(SADP)technique to provide good image contrast(or CDU,LWR)as well as good overlay,as for the 10 and 7 nm generations.In the BEOL,however,the 30-32 pitch cannot be realized by a single EUV exposure with enough printing defect process window.If this pitch is to be done by 193 nm immersion lithography,more than 6-8 exposures are needed with very complicated overlay result.For EUV,this can be done through self-aligned LELE with both good CD and overlay control.We have done an optimization of the photolithographic process parameters for the typical metal with a self-developed aerial image simulator based on rigorous coupled wave analysis(RCWA)algorithm and the Abbe imaging routine with an EUV absorption model which describes stochastics.We have calibrated our model with wafer exposure data from several photoresists under collaboration with IMEC.As we have presented last year,to accommodate all pitches under a logic design rule,as well as to provide enough CDU for the logic device performance,in DUV lithography,a typical minimum exposure latitude(EL)for the poly and metal layers can be set at,respectively,18%and 13%.In EUV,due to the existence of stochastics,13%EL,which corresponds to an imaging contrast of 40%,seems not enough for the metal trenches,and to obtain an imaging contrast close to 100%,which yields an EL of 31.4%means that we need to relax minimum pitch to above 41 nm(conventional imaging limit for 0.33NA).This is the best imaging contrast a photolithographic process can provide to reduce LWR and stochastics.In EUV,due to the significantly smaller numerical apertures compared to DUV,the aberration impact can cause much more pronounced image registration error,in order to satisfy 2.5 nm total overlay,the aberration induced shift needs to be kept under 0.2 nm.We have also studied shadowing effect and mask 3D scattering effect and our results will be provided for discussion.

Three-dimensional Monte Carlo simulation of bulk fin field effect transistor

In this paper, we investigate the performance of the bulk fin field effect transistor （FinFET） through a three- dimensional （3D） full band Monte Carlo simulator with quantum correction. Several scattering mechanisms, such as the acoustic and optical phonon scattering, the ionized impurity scattering, the impact ionization scattering and the surface roughness scattering are considered in our simulator. The effects of the substrate bias and the surface roughness scattering near the Si/SiO2 interface on the performance of bulk FinFET are mainly discussed in our work. Our results show that the on-current of bulk FinFET is sensitive to the surface roughness and that we can reduce the substrate leakage current by modulating the substrate bias voltage.