Poisson's ratios and S-wave velocities of the Xishancun landslide,Sichuan,China,inferred from high-frequency receiver functions of local earthquakes

Landslides are recurrent geological phenomena on Earth that cause heavy casualties and property losses annually.In this study,we use the V_(p)-k stacking and nonlinear waveform inversion methods of high-frequency receiver functions extracted from local earthquakes,to sequentially invert Poisson’s ratios and S-wave velocities of the Quaternary Xishancun landslide,which is composed of three segments,i.e.,h1,h2,and h3 from bottom to top.Our results show that Poisson’s ratio values are generally higher than 0.33 and that the S-wave velocities vary from 0.1 to 0.9 km s^(-1).High Poisson’s ratios(>0.44)are mainly distributed in the juncture regions between different segments,as well as the western edge of h2.These zones show significant variation in landslide thickness and are potentially hazardous areas.Low velocities of 0.05–0.2 km s^(-1)with thicknesses of 10–30m are widely observed in the lower layer of the landslide.The high Poisson’s ratios and low-velocity layer may be related to water-rich materials in these areas.Our study suggests that the high-frequency receiver functions from local earthquakes can be used to delineate geotechnical structures,which is valuable for landslide stability analysis and hazard mitigation.

Measurement of algae PSII photosynthetic parameters using high-frequency excitation flashes

We establish a system to measure the functional absorption cross section of photosystem lI （PSII） （O-PSII） and maximum quantum yield of photochemistry in PSII （Fv/Fm）. The system utilizes a sequence of high-frequency excitation flashes at microsecond intervals to induce a microsecond-level fluorescence yield curve. Parameters o-Psii and Fv/Fm are calculated by fitting the curve using nonlinear regression. Experimental results show that the relative standard deviation （RSD） of the system is less than 3%, and the correlation coefficient of Fv/Fm values measured by this system and those measured by pulse amplitude modulation method is 0.950.

High gain-bandwidth product Ge/Si tunneling avalanche photodiode with high-frequency tunneling effect

This study presents a theoretical investigation of a novel Ge/Si tunneling avalanche photodiode（TAPD）with an ultra-thin barrier layer between the absorption and p＋ contact layer. A high-frequency tunneling effect is introduced into the structure of the barrier layer to increase the high-frequency response when frequency is larger than 0.1 GHz, and the-3 dB bandwidth of the device increases evidently. The results demonstrate that the avalanche gain and-3 dB bandwidth of the TAPD can be influenced by the thickness and bandgap of the barrier layer.When the barrier thickness is 2 nm and the bandgap is 4.5 eV, the avalanche gain loss is negligible and the gainbandwidth product of the TAPD is 286 GHz, which is 18% higher than that of an avalanche photodiode without a barrier layer. The total noise in the TAPD was an order of magnitude smaller than that in APD without barrier layer.

High Order Deep Domain Decomposition Method for Solving High Frequency Interface Problems

This paper proposes a high order deep domain decomposition method(HOrderDeepDDM)for solving high-frequency interface problems,which combines high order deep neural network(HOrderDNN)with domain decomposition method(DDM).The main idea of HOrderDeepDDM is to divide the computational domain into some sub-domains by DDM,and apply HOrderDNNs to solve the high-frequency problem on each sub-domain.Besides,we consider an adaptive learning rate annealing method to balance the errors inside the sub-domains,on the interface and the boundary during the optimization process.The performance of HOrderDeepDDM is evaluated on high-frequency elliptic and Helmholtz interface problems.The results indicate that:HOrderDeepDDM inherits the ability of DeepDDM to handle discontinuous interface problems and the power of HOrderDNN to approximate high-frequency problems.In detail,HOrderDeepDDMs(p>1)could capture the high-frequency information very well.When compared to the deep domain decomposition method(DeepDDM),HOrderDeepDDMs(p>1)converge faster and achieve much smaller relative errors with the same number of trainable parameters.For example,when solving the high-frequency interface elliptic problems in Section 3.3.1,the minimum relative errors obtained by HOrderDeepDDMs(p=9)are one order of magnitude smaller than that obtained by DeepDDMs when the number of the parameters keeps the same,as shown in Fig.4.

A high-power and high-stability power supply design

Objective BEPCII is a high-performance collider with a design energy of 2.1 GeV. In order to obtain more physical experimentsand synchrotron radiation applications, BEPCII decided to carry out energy upgrading to 2.5 GeV. Insufficient energyof special magnet power supplies in collision zone is a key factor restricting BEPCII’s operation under 2.5 GeV energy.Therefore, three high-power and high-stability power supplies are designed for BEPCII energy upgrading.Methods The designed power supplies output part adopts high-frequency chopper modules parallel connected and adoptsdigital-analog hybrid control methods. The voltage loop regulator uses high-speed analog control, and current loop regulatoruses digital control which is based on FPGA.Conclusion The experimental data show that the output current stability of the developed power supplies is lower than50 ppm. The output current resolution is lower than 70 ppm. The developed power supplies can well meet the design requirementsof BEPCII energy upgrading.

Recent advances in micro-supercapacitors for AC line-filtering performance:From fundamental models to emerging applications

Recently,micro-supercapacitors(MSCs)have undergone major development as next-generation micro-electrochemical energy storage devices for self-powered,integrated,and wearable systems,thanks to their excellent performance capability.In particular,their rapid frequency response characteristics make them potential candidates to replace conventional capacitors and function as alternating current(AC)line filters to rectify pulse energy or as current ripple filters in the kHz range.However,few papers have been published about the associated fundamental device components,architectures,and correct characterization of MSCs applied in filter applications.In addition,it is a huge challenge to achieve a balance between capacitance and frequency response,not yet to be overcome.This review comprehensively summarizes recent advances in MSCs for AC line-filtering,from fundamental mechanisms to appropriate characterization and emerging applications.Special attention is given to progress in microfabrication strategies,electrode materials,and electrolytes for high-frequency MSCs.We also present perspectives and insights into the development of MSCs in different frequency ranges for AC line-filtering applications.