Disturbance failure mechanism of highly stressed rock in deep excavation:Current status and prospects

This article reviews the current status on the dynamic behavior of highly stressed rocks under disturbances.Firstly,the experimental apparatus,methods,and theories related to the disturbance dynamics of deep,high-stress rock are reviewed,followed by the introduction of scholars’research on deep rock deformation and failure from an energy perspective.Subsequently,with a backdrop of highstress phenomena in deep hard rock,such as rock bursts and core disking,we delve into the current state of research on rock microstructure analysis and residual stresses from the perspective of studying the energy storage mechanisms in rocks.Thereafter,the current state of research on the mechanical response and the energy dissipation of highly stressed rock formations is briefly retrospected.Finally,the insufficient aspects in the current research on the disturbance and failure mechanisms in deep,highly stressed rock formations are summarized,and prospects for future research are provided.This work provides new avenues for the research on the mechanical response and damage-fracture mechanisms of rocks under high-stress conditions.

A 128×128 SPAD LiDAR sensor with column-parallel 25 ps resolution TA-ADCs

This paper presents a design of single photon avalanche diode(SPAD)light detection and ranging(LiDAR)sensor with 128×128 pixels and 128 column-parallel time-to-analog-merged-analog-to-digital converts(TA-ADCs).Unlike the conventional TAC-based SPAD LiDAR sensor,in which the TAC and ADC are separately implemented,we propose to merge the TAC and ADC by sharing their capacitors,thus avoiding the analog readout noise of TAC’s output buffer,improving the conversion rate,and reducing chip area.The reverse start-stop logic is employed to reduce the power of the TA-ADC.Fabricated in a 180 nm CMOS process,our prototype sensor exhibits a timing resolution of 25 ps,a DNL of+0.30/−0.77 LSB,an INL of+1.41/−2.20 LSB,and a total power consumption of 190 mW.A flash LiDAR system based on this sensor demonstrates the function of 2D/3D imaging with 128×128 resolution,25 kHz inter-frame rate,and sub-centimeter ranging precision.

Residual stress measurement and analysis of siliceous slate-containing quartz veins

Engineering geological disasters such as rockburst have always been a critical factor affecting the safety of coal mine production.Thus,residual stress is considered a feasible method to explain these geomechanical phenomena.In this study,electron backscatter diffraction(EBSD)and optical microscopy were used to characterize the rock microcosm.A measuring area that met the requirements of X-ray diffraction(XRD)residual stress measurement was determined to account for the mechanism of rock residual stress.Then,the residual stress of a siliceous slate-containing quartz vein was measured and calculated using the sin^(2) ϕ method equipped with an X-ray diffractometer.Analysis of microscopic test results showed homogeneous areas with small particles within the millimeter range,meeting the requirements of XRD stress measurement statistics.Quartz was determined as the calibration mineral for slate samples containing quartz veins.The diffraction patterns of the(324)crystal plane were obtained under different ϕ and φ.The deviation direction of the diffraction peaks was consistent,indicating that the sample tested had residual stress.In addition,the principal residual stress within the quartz vein measured by XRD was compressive,ranging from 10 to 33 MPa.The maximum principal stress was parallel to the vein trend,whereas the minimum principal stress was perpendicular to the vein trend.Furthermore,the content of the low-angle boundary and twin boundary in the quartz veins was relatively high,which enhances the resistance of the rock mass to deformation and promotes the easy formation of strain concentrations,thereby resulting in residual stress.The proposed method for measuring residual stress can serve as a reference for subsequent observation and related research on residual stress in different types of rocks.

Research on Human-Vehicle-Road Friendliness Based on Improved SH-GH-ADD Control

The hub-driven virtual rail train is a novel urban transportation system that amalgamates the benefits of modern trams and buses.However,this system is plagued by issues such as decreased ride comfort and severe deformation of urban roads due to the increase in sprung mass and long-term rolling at the same position.To address these concerns and improve the human-vehicle-road friendliness of the virtual rail train,we propose an Improved Sky-Ground Hook and Acceleration-Driven Damper control(Improved SH-GH-ADD control)strategy for the semi-active suspension system.This control monitors the vibration acceleration signal of the unsprung mass in real-time and selects the mixed Sky-Hook and Acceleration-Driven Damper(SH-ADD)control or the mixed Ground-Hook and Acceleration-Driven Damper(GH-ADD)control based on the positive and negative values of the vibration acceleration of the unsprung mass.The Improved SH-GH-ADD control combines the advantages of SH-ADD control and GH-ADD control to achieve control of the sprung mass and unsprung mass in the full fre-quency band.Finally,through simulation and comparative analysis with traditional SH-ADD,GH-ADD,and mixed SH-GH control,we demonstrate the exceptional performance of the proposed algorithm.

Exploration of high-speed 3.0 THz imaging with a 65 nm CMOS process

This paper describes a promising route for the exploration and development of 3.0 THz sensing and imaging with FET-based power detectors in a standard 65 nm CMOS process.Based on the plasma-wave theory proposed by Dyakonov and Shur,we designed high-responsivity and low-noise multiple detectors for monitoring a pulse-mode 3.0 THz quantum cascade laser(QCL).Furthermore,we present a fully integrated high-speed 32×32-pixel 3.0 THz CMOS image sensor(CIS).The full CIS measures 2.81×5.39 mm^(2) and achieves a 423 V/W responsivity(Rv)and a 5.3 nW integral noise equivalent power(NEP)at room temperature.In experiments,we demonstrate a testing speed reaching 319 fps under continuous-wave(CW)illumina-tion of a 3.0 THz QCL.The results indicate that our terahertz CIS has excellent potential in cost-effective and commercial THz imaging and material detection.

CMOS image sensors in ISSCC 2023

In IEEE International Solid-State Circuits Conference(ISSCC)2023,CMOS process is still the dominating fabrication technology for image sensors,and three-dimensional(3D)wafer-stacked process with Cu–Cu pixel-level connection has been adopted to achieve small pixel size and high integration level.The development of CMOS image sensors(CIS)is still focusing on the trends of high performance and more functionalities,such as hybrid event-based vision sensor(EVS)and terahertz(THz)/X-ray image sensor.

不同发酵条件对小台农芒果酒中的Vc含量及风味的影响

为了研究不同发酵条件对小台农芒果酒中的Vc含量和风味的影响,以海南小台农芒果为主要原料,以不同梯度的果胶酶、酵母添加量和发酵时间为单因素实验,测定Vc、总糖、滴定酸、可溶性固形物等指标,在此基础上进行L33正交实验,确定最佳酿造工艺。结果筛选出两种工艺,一种工艺为果胶酶添加量为0.15%,酵母添加量为0.20 g/L,发酵时间为7 d,此工艺下酿造的小台农芒果酒总体评分最高为85分,Vc为33.89 mg/100 g,具有浓郁的芒果香气,酒体结构感强,酒香与果香融合较好,余味较长;另一种工艺为果胶酶添加量0.20%,酵母添加量0.20 g/L,发酵时间8 d,在此工艺下芒果酒最终评分为74,Vc含量为37.27 mg/100 g,但其酒精度较高,酒体较淡薄,结构感不强,后味略苦。因此,从风味上考虑,则优选第一种工艺为佳,果胶酶添加量为0.15%、酵母添加量为0.20g/L、发酵时间为7d;从Vc含量上考虑,则第二种工艺为最佳选择,果胶酶添加量为0.2%、酵母添加量为0.20 g/L、发酵时间为8d。

Adipocyte-derived SFRP5 inhibits breast cancer cells migration and invasion through Wnt and epithelial-mesenchymal transition signaling pathways

Objective:Obesity is closely associated with metastasis in breast cancer patients.Secreted frizzled-related protein 5(SFRP5),one of the novel adipokines with anti-inflammatory properties,is associated with obesity.This study aims to study the role of SFRP5 in the crosstalk between obesity and breast cancer metastasis and identify the underlying mechanism.Methods:3T3-L1 pre-adipocytes were differentiated to mature adipocytes and a hypertrophic adipocyte model was induced with palmitic acid(PA).Cell motility was measured in MDA-MB-231 and MCF-7 breast cancer cells co-cultured with adipocytes conditioned medium(CM)with or without SFRP5 protein.Wnt and epithelialmesenchymal transition(EMT)signal pathways were investigated by western blot.Circulating SFRP5 level in 218 breast cancer patients and the association with clinicopathologic characteristics of breast cancer were further determined.Online databases ENCORI and PREDICT Plus were used to exam the link between SFRP5 and prognosis.Results:Reduced SFRP5 level was detected in the hypertrophic adipocyte model.Recombinant SFRP5 protein inhibited MDA-MB-231 and MCF-7 cells invasion and migration induced by PA-treated adipocyte CM,and SFRP5 inhibition by specific antibody reversed the effect of SFRP5.Furthermore,SFRP5 significantly inhibited Wnt and downstream EMT in breast cancer cells.Low circulating SFRP5 level correlated with body mass index(BMI),lymph node(LN)metastasis,TNM stage and high Ki67 expression in breast cancer patients.Increased SFRP5 level was associated with favorable predicted survival.Kaplan-Meier curves showed high SFRP5 level in tumor tissue was associated with better outcome of breast cancer patients.Conclusions:Our findings demonstrated SFRP5 is a vital adipokine that mediates the crosslink between obesity and the metastatic potential of breast cancer.Promotion of SFRP5 expression in the adipose microenvironment may represent a novel approach for preventing breast cancer metastasis.

Numerical Study on Rock Breaking Mechanism of Supercritical CO_(2)Jet Based on Smoothed Particle Hydrodynamics

Supercritical carbon dioxide(Sc-CO_(2))jet rock breaking is a nonlinear impact dynamics problem involving many factors.Considering the complexity of the physical properties of the Sc-CO_(2)jet and the mesh distortion problem in dealing with large deformation problems using the finite element method,the smoothed particle hydrodynamics(SPH)method is used to simulate and analyze the rock breaking process by Sc-CO_(2)jet based on the derivation of the jet velocity-density evolution mathematical model.The results indicate that there exists an optimal rock breaking temperature by Sc-CO_(2).The volume and length of the rock fracture increase with the rising of the jet temperature but falls when the jet temperature exceeds 340 K.With more complicated perforation shapes and larger fracture volumes,the Sc-CO_(2)jet can yield a rock breaking more effectively than water jet,The stress analysis shows that the Sc-CO_(2)rock fracturing process could be reasonably divided into three stages,namely the fracture accumulation stage,the rapid failure stage,and the breaking stabilization stage.The high diffusivity of Sc-CO_(2)is identified as the primary cause of the stress fluctuation and W-shaped fracture morphology.The simulated and calculated results are generally in conformity with the published experimental data.This study provides theoretical guidance for further study on Sc-CO_(2)fracturing mechanism and rock breaking efficiency.

Asymmetric coherent rainbows induced by liquid convection

Coherent rainbows can be formed by focusing white-light laser into liquids.They are bilaterally symmetric interference rings with various shapes.Such interference rings arise from the temperature distribution of the liquid induced by laser heating,i.e.,thermal lens effect,which changes the refractive index locally and thus the optical path difference.The up-down asymmetry of the interference rings is caused by convection in the liquid.With the increase of the viscosity,the interference rings change their shape from oval to circular shape.After a shutter is opened and the laser shines into the liquid,the interference rings are circular at the beginning.As time goes on,they gradually turn into an oval shape.Let the liquid go a free-fall at the beginning,the interference rings remain circular.All the three experiments have confirmed that the asymmetric interference rings are due to convection in the liquid associated with thermal lens effect.We also numerically simulate the two-dimensional heat conduction with and without convection,whose results agree well with our experimental observations.

Preface to the Special Issue on Advanced Analog and Mixed- Mode Integrated Circuits

High performance analog and mixed signal circuits are strongly demanded in todays’system on chip systems.They found pervasive applications in A/D or D/A conversion,power management,radio frequency(RF)signal sensing and processing,clock generation,etc.In this special issue,we collected 7 comprehensive reviews and 2 research articles from leading research groups,which presented state-of-art design techniques and insight forecast of development trend in this hot area.

Molecularly Imprinted Micro-Solid-Phase Extraction for the Selective Determination of Phenolic Compounds in Environmental Water Samples with High Performance Liquid Chromatraphy

2,4,6-trichlorophenol molecularly imprinted suspension polymer has been prepared and applied to the molecularly imprinted micro-solid-phase extraction procedure for selective preconcentration of phenolic compounds from environmental water samples. The influence of functional monomer, cross-linker, polymerization condition, porogen, and the ratio of template molecule and functional monomer to cross-linker on the size of the obtained particles were investigated. It was found that methyacrylic acid as functional monomer, divinylbenzene as cross-linker, the molar ratio of template molecule and functional monomer to cross-linker was 1:4:20, the amount of AIBN was 100 mg, ultraviolet radiation at 365 nm were the optimal conditions, and at these conditions, the polymers had the best adsorption efficiency and had the monodispersity of 2 - 3 μm microsphere particles. The characteristics of the MIMSPE method were valid by high performance liquid chromatography. This MIMSPE-HPLC method has been successfully applied to the direct preconcentration and determination of phenolic compounds (phenol, 4-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol, pentachlorophenol) in environmental water samples.

Terahertz spectroscopy of water in nonionic reverse micelles

The dynamics of water within a nanopool of a reverse micelle is heavily affected by the amphiphilic interface.In this work,the terahertz(THz)spectra of cyclohexane/Igepal/water nonionic reverse micelle mixture are measured by THz timedomain spectroscopy and analyzed with two Debye models and complex permittivity of background with volume ratios.Based on the fitted parameters of bulk and fast water,the molar concentration of all kinds of water molecules and hydration water molecule number per Igepal molecule are calculated.We find that slow hydration water has the highest proportion in water when the radius parameterω_(0)<10,while bulk water becomes the main component whenω_(0)≥10.The feature radius ratio of nonhydrated and hydrated water to total water nanopool is roughly obtained from 0.39 to 0.85 with increasingω_(0).

智能视觉芯片

智能视觉芯片(视觉芯片)是一种集成视觉传感器、高能效处理器、存储器的片上系统芯片,在自动驾驶、安防监控、机器人视觉等领域都具有广泛的应用价值.硅基CMOS工艺上既可以实现大规模的视觉传感器,也可制备大规模存储器和处理器,所以基于硅基CMOS工艺,人们可以借助光电子、微电子混合集成技术实现感存算一体化融合的视觉芯片,以克服传统视觉系统中图像串行传输和处理的瓶颈,有效降低处理延迟并提高智能化水平.构建视觉芯片需要突破高性能视觉图像传感器设计、高能效视觉图像处理器设计、视觉处理算法以及传感器/存储器/处理器一体化集成等多方面的关键问题.本文首先介绍视觉芯片的概念和架构,然后分别介绍视觉芯片各项关键技术的发展现状,最后简述视觉芯片的未来发展方向.

基于各向异性二维半导体GeSe的双波段实时目标识别图像传感器

实时多光谱成像技术能够显著增强图像传感器的感知能力,有效提高基于实时成像和计算机视觉人工智能系统的准确性和鲁棒性,在自动驾驶、遥感和安防监控等系统中具有广泛的应用前景.然而,多光谱成像系统的构建常常受到色散元件或器件的选择性吸收带来的复杂性限制.为解决这一问题,本文基于新型各向异性二维半导体材料GeSe开发了一个高集成的可见光/近红外图像传感器,以实现实时多光谱成像的简化及小型化.该系统基于GeSe光电探测器和图像传感器在可见光/近红外波段下光电流强度随不同偏振角的变化趋势,能够识别入射光的波段信息,从而完成实时目标检测和波段信息识别,在模拟“自动驾驶”不同演示场景中可以取得良好的准确性和稳定性,实现了实时多光谱成像演示系统的集成化及小型化.

A fault segment location method for distribution networks based on spiking neural P systems and Bayesian estimation

With the increasing scale of distribution networks and the mass access of distributed generation,traditional central-ized fault location methods can no longer meet the performance requirements of speed and high accuracy.There-fore,this paper proposes a fault segment location method based on spiking neural P systems and Bayesian estimation for distribution networks with distributed generation.First,the distribution network system topology is decoupled into single-branch networks.A spiking neural P system with excitatory and inhibitory synapses is then proposed to model the suspected faulty segment,and its matrix reasoning algorithm is executed to obtain a preliminary set of location results.Finally,the Bayesian estimation and contradiction principle are applied to verify and correct the ini-tial results to obtain the final location results.Simulation results based on the IEEE 33-node system validate the feasi-bility and effectiveness of the proposed method.

Plasma-based terahertz wave photonics in gas and liquid phases

Ultra-broadband,intense,coherent terahertz(THz)radiation can be generated,detected,and manipulated using laser-induced gas or liquid plasma as both the THz wave transmitter and detector,with a frequency coverage spanning across and beyond the whole THz gap."Such a research topic is termed plasma-based THz wave photonics in gas and liquid phases."In this paper,we review the most important experimental and theoretical works of the topic in the non-relativistic region with pump laser intensity below 1018 W/cm^(2).

Interaction of colliding laser pulses with gas plasma for broadband coherent terahertz wave generation

Colliding of two counter-propagating laser pulses is a widely used approach to create a laser field or intensity surge.We experimentally demonstrate broadband coherent terahertz(THz)radiation generation through the interaction of colliding laser pulses with gas plasma.The THz radiation has a dipole-like emission pattern perpendicular to the laser propagation direction with a detected peak electric field 1 order of magnitude higher than that by single pulse excitation.As a proof-of-concept demonstration,it provides a deep insight into the physical picture of laser–plasma interaction,exploits an important option to the promising plasma-based THz source,and may find more applications in THz nonlinear near-field imaging and spectroscopy.

An Improved Training Algorithm Based on Ensemble Penalized Cox Regression for Predicting Absolute Cancer Risk

Introduction:Biases in cancer incidence characteristics have led to significant imbalances in databases constructed by prospective cohort studies.Since they use imbalanced databases,many traditional algorithms for training cancer risk prediction models perform poorly.Methods:To improve prediction performance,we introduced a Bagging ensemble framework to an absolute risk model based on ensemble penalized Cox regression(EPCR).We then tested whether the EPCR model outperformed other traditional regression models by varying the censoring rate of the simulated data.Results:Six different simulation studies were performed with 100 replicates.To assess model performance,we calculated mean false discovery rate,false omission rate,true positive rate,true negative rate,and the areas under the receiver operating characteristic curve(AUC)values.We found that the EPCR procedure could reduce the false discovery rate(FDR)for important variables at the same true positive rate(TPR),thereby achieving more accurate variable screening.In addition,we used the EPCR procedure to build a breast cancer risk prediction model based on the Breast Cancer Cohort Study in Chinese Women database.AUCs for 3-and 5-year predictions were 0.691 and 0.642,representing improvements of 0.189 and 0.117 over the classical Gail model,respectively.Discussion:We conclude that the EPCR procedure can overcome challenges posed by imbalanced data and improve the performance of cancer risk assessment tools.

Breast Cancer Awareness and Association with Frequency of Screening Among Women—China,2020

Summary What is already known about this topic?Breast cancer awareness plays a crucial role in promoting screening attendance,enabling early detection,and improving survival rates associated with breast cancer.Nevertheless,a persistent issue is the low public awareness of breast cancer warning signs and risk factors.