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Three-dimensional stress variation characteristics in deep hard rock of CJPL-Ⅱ project based on in-situ monitoring

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International Journal of Mining Science and Technology 2024年第2期34卷 179-195页

作者： Minzong zheng Shaojun Li Zejie Feng Huaisheng xu Yaxun xiao State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China University of Chinese Academy of Sciences Beijing 100049China

In deep hard rock excavation, stress plays a pivotal role in inducing stress-controlled failure. While the impact of excavation-induced stress disturbance on rock failure and tunnel stability has undergone comprehensive examination through laboratory tests and numerical simulations, its validation through insitu stress tests remains unexplored. This study analyzes the three-dimensional stress changes in the surrounding rock at various depths, monitored during the excavation of B2 Lab in China Jinping Underground Laboratory Phase Ⅱ(CJPL-Ⅱ). The investigation delves into the three-dimensional stress variation characteristics in deep hard rock, encompassing stress components and principal stress. The results indicate changes in both the magnitude and direction of the principal stress during tunnel excavation. To quantitatively describe the degree of stress disturbance, a series of stress evaluation indexes are established based on the distances between stress tensors, including the stress disturbance index(SDI), the principal stress magnitude disturbance index(SDIm), and the principal stress direction disturbance index(SDId). The SDI indicates the greatest stress disturbance in the surrounding rock is 4.5 m from the tunnel wall in B2 Lab. SDIm shows that the principal stress magnitude disturbance peaks at2.5 m from the tunnel wall. SDId reveals that the largest change in principal stress direction does not necessarily occur near the tunnel wall but at a specific depth from it. The established relationship between SDI and the depth of the excavation damaged zone(EDZ) can serve as a criterion for determining the depth of the EDZ in deep hard rock engineering. Additionally, it provides a reference for future construction and support considerations.

关键词： Disturbance stress Tensor distance Stress disturbance index Principal stress direction Underground research laboratory

Unconventional Fluorescent and Multi-responsive Polysiloxane:Synthesis,Characterization and Biological Applications

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Chinese Journal of Polymer Science 2024年第5期42卷 579-590,I0006页

作者： xiao-Di Li Shu-Sheng Li xu-Bao Jiang xiao-Li Zhu Xiang zheng Kong College of Chemistry and Chemical Engineering University of JinanJinan250022China College of Chemical Engineering Tianjin UniversityTianjin300072China Foshan(Southern China)Institute for New Materials Foshan528200China

Owing to their high significance in fundamental study and diverse applications,stimuli-responsive and fluorescent polymers,particularly those with cluster-triggered emission(CTE)featured by non-conjugated chromophores,have drawn tremendous attention in recent *** this work,fluorescent and multi-responsive polysiloxane(FRPS)was synthesized by hydrolytic condensation polymerization of 3-aminopropyl methyl diethoxysilane(APMS)with 3-(N-isopropyl propionamide)iminopropyl methyl diethoxysilane(APMS-NIP),which was formed in situ through aza-Michael addition between APMS and N-isopropyl *** was not only highly sensitive to temperature,pH and CO_(2) in water,but also showed an enhanced and stimuli-adjustable fluorescence *** effects of monomer feeding,pH and CO_(2) on its lower critical solution temperature and fluorescent property were *** fluorescence emission was ascribed to CTE *** addition,FRPS was shown to be highly potential as physiological indicator for cell imaging,and for controlled release and trace detection of *** study provides therefore a type of stimuli-responsive and fluorescent material for potential applications in biomedical fields,and it is also of great significance for understanding of the fluorescence mechanism of polysiloxane-based stimuli-responsive polymers.

关键词： Polysiloxane Multi-responsiveness Cluster-triggered emission Cell imaging Controlled drug release

A review of development methods and EOR technologies for carbonate reservoirs

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Petroleum Science 2020年第4期17卷 990-1013页

作者： zheng-xiao xu Song-Yan Li Bin-Fei Li Dan-Qi Chen Zhong-Yun Liu Zhao-Min Li School of Petroleum Engineering China University of Petroleum(East China)Qingdao 266580ShandongChina Key Laboratory of Unconventional Oil and Gas Development China University of Petroleum(East China)Ministry of EducationQingdao 266580ShandongChina Sinopec Group Beijing 100728China

Carbonate reservoirs worldwide are complex in structure,diverse in form,and highly *** on these characteristics,the reservoir stimulation technologies and fluid flow characteristics of carbonate reservoirs are briefly described in this *** development methods and EOR technologies of carbonate reservoirs are systematically summarized,the relevant mechanisms are analyzed,and the application status of oil fields is *** challenges in the development of carbonate reservoirs are discussed,and future research directions are *** the current development processes of carbonate reservoirs,water flooding and gas flooding remain the primary means but are often prone to channeling *** flooding is an effective method of tertiary oil recovery,but the harsh formation conditions require high-performance chemical *** application of emerging technologies can enhance the oil recovery efficiency and environmental friendliness to a certain extent,which is welcome in hard-to-recover areas such as heavy oil reservoirs,but the economic cost is often *** future research on EOR technologies,flow field control and flow channel plugging will be the potential directions of traditional development methods,and the application of nanoparticles will revolutionize the chemical EOR *** the basis of diversified reservoir stimulation,combined with a variety of modern data processing schemes,multichannel EOR technologies are being developed to realize the systematic,intelligent,and cost-effective development of carbonate reservoirs.

关键词： Carbonate reservoir Reservoir stimulation Flow characteristic Development method EOR technology

Field-assisted machining of difficult-to-machine materials

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International Journal of Extreme Manufacturing 2024年第3期6卷 39-89页

作者： Jianguo Zhang zhengding zheng Kai Huang Chuangting Lin Weiqi Huang xiao Chen Junfeng xiao Jianfeng xu State Key Laboratory of Intelligent Manufacturing Equipment and Technology School of Mechanical Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074People’s Republic of China School of Mechanical Engineering Hubei University of TechnologyWuhan 430068People’s Republic of China

Difficult-to-machine materials (DMMs) are extensively applied in critical fields such as aviation,semiconductor,biomedicine,and other key fields due to their excellent material ***,traditional machining technologies often struggle to achieve ultra-precision with DMMs resulting from poor surface quality and low processing *** recent years,field-assisted machining (FAM) technology has emerged as a new generation of machining technology based on innovative principles such as laser heating,tool vibration,magnetic magnetization,and plasma modification,providing a new solution for improving the machinability of *** technology not only addresses these limitations of traditional machining methods,but also has become a hot topic of research in the domain of ultra-precision machining of *** new methods and principles have been introduced and investigated one after another,yet few studies have presented a comprehensive analysis and *** fill this gap and understand the development trend of FAM,this study provides an important overview of FAM,covering different assisted machining methods,application effects,mechanism analysis,and equipment *** current deficiencies and future challenges of FAM are summarized to lay the foundation for the further development of multi-field hybrid assisted and intelligent FAM technologies.

关键词： field-assisted machining difficult-to-machine materials materials removal mechanism surface integrity

Fe3O4@SiO2-Protein A-oHSV/CD63 Ab for Capturing Virus and Exosomes

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Journal of Analysis and Testing 2024年第3期8卷 335-350页

作者： Wenqing zheng Pingyi zheng Ran Zhao Xinyu xu xiao Zhang xiaoqian Yuan Ying xu Zichuan Liu Youxin Li Tianjin Key Laboratory for Modern Drug Delivery and High-Eiffciency Collaborative Innovation Center of Chemical Science and Engineering School of Pharmaceutical Science and Technology Faculty of MedicineTianjin University

Protein A modi?ed magnetic spheres (Fe3O4@SiO2-Protein A) with 22.7 emu/g saturation magnetization were prepared and *** spheres had a diameter of 10 nm and was stable up to 229.2°C,and can bond 19.694 mg/g of Protein *** Fe3O4@SiO2-Protein A was?rstly combined with oHSV-BJ-2-A antibody to capture oHSV from disease venom,and the amount of binding virus was 1.92×107to 3.44×107PFU/***3O4@SiO2-Protein A was modi?ed with CD63 antibody,which was further?xed using dissuccinimide octylate （DSS） as a crosslinking *** prepared Fe3O4@Si O2-Protein A-CD63 Ab was useful in isolating and enriching exosomes from cell *** with commercial kits,Fe3O4@SiO2-Protein A-CD63 Ab demonstrated a better puri?cation e?ect,which was successfully monitored using capillary *** total content of exosomes protein extracted using Fe3O4@SiO2-Protein A-CD63 was 3.4 mg/g,which was obviously higher than that reported in some *** addition,Fe3O4@SiO2-Protein A-CD63 Ab also showed its repeatability through bonding and elution of 5 cycles,which was e?ective in cost *** indicated Fe3O4@SiO2-Protein A-CD63 Ab had the potential for large-scale puri?cation of exosomes in practical applications.

关键词： Antibody Exosome Herpes simplex virus Immunomagnetic spheres

Surface Polarization Effects on Collapse Transition of Polyelectrolyte Brushes

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Chinese Journal of Polymer Science 2024年第9期42卷 1313-1320,I0006页

作者： xiao-Fei xu State Key Laboratory of Chemical Engineering and School of Chemical Engineering East China University of Science and TechnologyShanghai200237China

Polyelectrolyte brushes(PEBs)are commonly used to modify surface that have attracted great research *** dielectric permittivity of the grafted surface is typically significantly different from that of solution,which results in surface polarization(SP)effect with a jump of electric *** is thus important to study how SP alters the PEB’s structure and *** this work,the SP effects on PEB structure was studied using a statistical thermodynamic *** free energy functional to describe SP effect was constructed by using the image-charge ***,the electrostatic potential was solved from a modified Poisson-Boltzmann equation taking the ion solvation effect into *** the absence of SP,the thickness of PEB exhibited a continuous collapse transition when decreasing the solvent *** the presence of SP,the collapse became a jump-like *** energy analysis showed that the long-range Coulombic interaction dominated the transition because of the enhanced counterion condensation in the presence of *** theory provides an effective tool to study SP effect on PEBs,and the results explain the underlying physics in PEB collapse transition.

关键词： Surface polarization Polyelectrolyte brush Image charge Ion solvation Polyelectrolyte collapse transition

A Secure Cryptographic System Based on Steady-State Visual Evoked Potential Brain-Computer Interface Technology

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Journal of Systems Science and Information 2024年第3期12卷 423-432页

作者： xu xiao Feiyang ZHANG Wenhan YIN Dezhi zheng College of Life and Environmental Science Minzu University of ChinaBeijing 100081China School of Instrumentation and Optoelectronic Engineering Beihang UniversityBeijing 100191China Advanced Research Institute of Multidisciplinary Sciences Beijing Institute of TechnologyBeijing 100081China

Addressing the vulnerability of contact-based keyboard password systems to disclosure,this paper proposes and validates the feasibility of a non-contact secure password system based on brain-computer interface(BCI)technology that detects steady-state visual evoked potential(SSVEP)*** system first lets a testee look at a digital stimulus source flashing at a specific frequency,and uses a wearable dry electrode sensor to collect the SSVEP ***,a canonical correlation analysis method is applied to analyze the frequency of the stimulus source that the testee is looking at,and feeds back a code result through ***,after all password codes are input,the system makes a judgment and provides visual feedback to the *** were conducted to test the accuracy of the system,where twelve stimulus target frequencies between 10-16Hz were selected within the easily recognizable flicker frequency range of human brain,and each of them was tested for 12 *** results demonstrate that this SSVEP-BCI-based system is feasible,achieving an average accuracy rate of 97.2%,and exhibits promising applications in various domains such as financial transactions and identity recognition.

关键词： brain computer interface steady-state visual evoked potential password system

CNN-LSTM based incremental attention mechanism enabled phase-space reconstruction for chaotic time series prediction

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Journal of Electronic Science and Technology 2024年第2期22卷 77-90页

作者： xiao-Qian Lu Jun Tian Qiang Liao zheng-Wu xu Lu Gan Bidding and Purchasing Center University of Electronic Science and Technology of ChinaChengdu611731China Yibin Research Institute University of Electronic Science and Technology of ChinaYibin644000China School of Information and Communication Engineering University of Electronic Science and Technology of ChinaChengdu611731China

To improve the prediction accuracy of chaotic time series and reconstruct a more reasonable phase space structure of the prediction network,we propose a convolutional neural network-long short-term memory(CNN-LSTM)prediction model based on the incremental attention ***,a traversal search is conducted through the traversal layer for finite parameters in the phase ***,an incremental attention layer is utilized for parameter judgment based on the dimension weight criteria(DWC).The phase space parameters that best meet DWC are selected and fed into the input ***,the constructed CNN-LSTM network extracts spatio-temporal features and provides the final prediction *** model is verified using Logistic,Lorenz,and sunspot chaotic time series,and the performance is compared from the two dimensions of prediction accuracy and network phase space ***,the CNN-LSTM network based on incremental attention is compared with long short-term memory(LSTM),convolutional neural network(CNN),recurrent neural network(RNN),and support vector regression(SVR)for prediction *** experiment results indicate that the proposed composite network model possesses enhanced capability in extracting temporal features and achieves higher prediction ***,the algorithm to estimate the phase space parameter is compared with the traditional CAO,false nearest neighbor,and C-C,three typical methods for determining the chaotic phase space *** experiments reveal that the phase space parameter estimation algorithm based on the incremental attention mechanism is superior in prediction accuracy compared with the traditional phase space reconstruction method in five networks,including CNN-LSTM,LSTM,CNN,RNN,and SVR.

关键词： Chaotic time series Incremental attention mechanism Phase-space reconstruction

Nitrite-catalyzed economic and sustainable bromocyclization of tryptamines/tryptophols to access hexahydropyrrolo[2,3-b]indoles/tetrahydrofuroindolines in batch and flow

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Chinese Chemical Letters 2024年第7期35卷 247-252页

作者： xiao xiao Biao Chen Jia-Wei Li Jun-Bo zheng xu Wang Hang Zhao Fen-Er Chen Institute of Pharmaceutical Science and Technology Collaborative Innovation Center of Yangtze River Delta Region Green PharmaceuticalsZhejiang University of TechnologyHangzhou 310014China College of Chemistry and Chemical Engineering Jiangxi Normal UniversityNanchang 330022China Engineering Center of Catalysis and Synthesis for Chiral Molecules Department of ChemistryFudan UniversityShanghai 200433China Shanghai Engineering Center of Industrial Asymmetric Catalysis for Chiral Drugs Shanghai 200433China

A highly efficient and concise bromocyclization has been successfully achieved,in which tryptamine/tryptophol derivates can be transformed to valuable HPI/TFI scaffolds with economic and green ***,a controllable cascade transformation of bromocyclization and aromatic bromination has also been smoothly achieved to form dibrominated HPIs and *** could be successfully scaled up under both the batch process and a continuous flow *** most remarkable peculiarity of our process over all previous methods is that the generated water is the major ***,successful application of this new protocol has been demonstrated by the pharmaceutical and natural products syntheses.

关键词： Tryptamines and tryptophols Nitrite Economic and sustainable bromocyclization HPI and TFI structures Bath and flow