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Evaluation and prediction of earth pressure balance shield performance in complex rock strata:A case study in Dalian,China

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第6期15卷 1491-1505页

作者： xiang Shen Dajun Yuan Xing-tao Lin xiangsheng chen Yuansheng Peng College of Civil and Transportation Engineering Shenzhen UniversityShenzhen518060China Key Laboratory for Resilient Infrastructures of Coastal Cities of Ministry of Education Shenzhen UniversityShenzhen518060China Shenzhen Key Laboratory of Green Efficient and Intelligent Construction of Underground Metro StationShenzhen518060China Key Laboratory of Urban Underground Engineering of Ministry of Education Beijing Jiaotong UniversityBeijing100044China

This research explores the potential for the evaluation and prediction of earth pressure balance shield performance based on a gray system model.The research focuses on a shield tunnel excavated for Metro Line 2 in Dalian,China.Due to the large error between the initial geological exploration data and real strata,the project construction is extremely difficult.In view of the current situation regarding the project,a quantitative method for evaluating the tunneling efficiency was proposed using cutterhead rotation(R),advance speed(S),total thrust(F)and torque(T).A total of 80 datasets with three input parameters and one output variable(F or T)were collected from this project,and a prediction framework based gray system model was established.Based on the prediction model,five prediction schemes were set up.Through error analysis,the optimal prediction scheme was obtained from the five schemes.The parametric investigation performed indicates that the relationships between F and the three input variables in the gray system model harmonize with the theoretical explanation.The case shows that the shield tunneling performance and efficiency are improved by the tunneling parameter prediction model based on the gray system model.

关键词： Evaluation of earth pressure balance shield performance Gray system model Metro construction Rock strata Field data prediction

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Fabrication of porous TiZrNbTa high-entropy alloys/Ti composite with high strength and low Young’s modulus using a novel MgO space holder

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Journal of Materials Science & Technology 2023年第36期167卷 59-73页

作者： tao xiang Jie chen Weizong Bao Shuyan Zhong Peng Du Guoqiang Xie School of Materials Science and Engineering Harbin Institute of Technology(Shenzhen)Shenzhen 518055China State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China

Stress shielding is caused by the mismatch of stiffness between bone and implant materials,which may give rise to bone resorption and loosening,thereby causing implantation failure.There is a huge gap between Young’s modulus of human bone and low Young’s modulusβTi alloys.A porous structure design can achieve the target of low Young’s modulus,and thus achieve the matching between human bone and implant materials.However,a suitable space holder(SH)that can be applied at high temperatures and sintering pressure has not been reported.In this study,the TiZrNbTa/Ti titanium matrix composite(TMC)with high strength and large ductility was used as scaffold materials and combined the SH technique with the spark plasma sintering(SPS)technique to obtain a porous structure.A novel space holder,i.e.,MgO particles was adopted,which can withstand high-temperature sintering accompanied by a sintering pressure.The porous TiZrNbTa/Ti with 40 vol.%MgO added exhibits a maximum strength of 345.9±10.4 MPa and Young’s modulus of 24.72±0.20 GPa,respectively.It possesses higher strength compared with human bone and matches Young’s modulus of human bone,which exhibits great potential for clinical application.

关键词： TiZrNbTa/Ti titanium matrix composite MgO space holder Low Young’s modulus High strength

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Evolution laws of microstructures and mechanical properties during heat treatments for near-αhigh-temperature titanium alloys

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International Journal of Minerals,Metallurgy and Materials 2022年第8期29卷 1596-1607页

作者： Xiaozhao Ma Zhilei xiang tao Li Yilan chen Yingying Liu Ziyong chen Qun Shu Faculty of Materials and Manufacturing Beijing University of TechnologyBeijing 100124China Pinggao Group CO. LTDState Grid Corporation of ChinaPingdingshan 467000China Aviation Industry of China(AVIC)Manufacture technology institute Beijing 100024China

Evolution laws of microstructures,mechanical properties,and fractographs after different solution temperatures were investigated through various analysis methods.With the increasing solution temperatures,contents of the primaryαphase decreased,and contents of transformedβstructures increased.Lamellarαgrains dominated the characteristics of transformedβstructures,and widths of secondaryαlamellas increased monotonously.For as-forged alloy,large silicides with equiaxed and rod-like morphologies,and nano-scale silicides were found.Silicides with large sizes might be(Ti,Zr,Nb)_(5)Si_(3) and(Ti,Zr,Nb)_(6)Si_(3).Rod-like silicides with small sizes precipitated in retainedβphase,exhibiting near 45°angles withα/βboundaries.Retainedβphases in as-heat treated alloys were incontinuous.980STA exhibited an excellent combination of room temperature(RT)and 650°C mechanical properties.Characteristics of fracture surfaces largely depended on the evolutions of microstructures.Meanwhile,silicides promoted the formation of mico-voids.

关键词： solution temperatures microstructures mechanical properties fractographs silicides

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A Cooperative Security Monitoring Mechanism Aided by Optimal Multiple Slave Cluster Heads for UASNs

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China Communications 2023年第5期20卷 148-169页

作者： Yougan chen Wei Wang xiang Sun Yi tao Zhenwen Liu Xiaomei Xu Key Laboratory of Underwater Acoustic Communication and Marine Information Technology Xiamen UniversityXiamen 361005China Shenzhen Research Institute of Xiamen University Shenzhen 518000China Dongshan Swire Marine Station College of Ocean and Earth SciencesXiamen UniversityXiamen 361102China State Key Laboratory of Robotics Shenyang Institute of AutomationChinese Academy of SciencesShenyang 110016China Department of Electrical and Computer Engineering University of New MexicoAlbuquerqueNM 87131USA College of Harbour and Coastal Engineering Jimei UniversityXiamen 361021China

As each cluster head(CH)sensor node is used to aggregate,fuse,and forward data from different sensor nodes in an underwater acoustic sensor network(UASN),guaranteeing the data security in a CH is very critical.In this paper,a cooperative security monitoring mechanism aided by multiple slave cluster heads(SCHs)is proposed to keep track of the data security of a CH.By designing a low complexity“equilateral triangle algorithm(ETA)”,the optimal SCHs(named as ETA-based multiple SCHs)are selected from the candidate SCHs so as to improve the dispersion and coverage of SCHs and achieve largescale data security monitoring.In addition,by analyzing the entire monitoring process,the close form expression of the probability of the failure attack identification for the SCHs with respect to the probability of attack launched by ordinary nodes is deduced.The simulation results show that the proposed optimal ETA-based multiple SCH cooperation scheme has lower probability of the failure attack identification than that of the existing schemes.In addition,the numerical simulation results are consistent with the theoretical analysis results,thus verifying the effectiveness of the proposed scheme.

关键词： underwater acoustic sensor networks data security cluster head nodes optimal location distribution of multiple slave cluster head nodes

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Time-restricted feeding is an intervention against excessive dark-phase sleepiness induced by obesogenic diet

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National Science Review 2023年第1期10卷 127-142页

作者： Xu Wang Keke Xing Mengge He Ting He Xinkuan xiang tao chen Luoying Zhang Haohong Li Britton Chance Center for Biomedical Photonics Wuhan National Laboratory for OptoelectronicsHuazhong University of Science and Technology MOE Key Laboratory for Biomedical Photonics Collaborative Innovation Center for Biomedical Engineering School of Engineering SciencesHuazhong University of Science and Technology Department of Anatomy Histology &Embryology Fourth Military Medical University Key Laboratory of Molecular Biophysics of Ministry of Education College of Life Science and Technology Huazhong University of Science and Technology Department of Neurobiology Affiliated Mental Health Center &Hangzhou Seventh People's HospitalZhejiang University School of Medicine Liangzhu Laboratory The MOE Frontier Research Center of Brain &Brain-machine Integration State Key Laboratory of Brain-machine Intelligence

High-fat diet(HFD)-induced obesity is a growing epidemic and major health concern.While excessive daytime sleepiness(EDS) is a common symptom of HFD-induced obesity,preliminary findings suggest that reduced wakefulness could be improved with time-restricted feeding(TRF).At present,however,the underlying neural mechanisms remain largely unknown.The paraventricular thalamic nucleus(PVT) plays a role in maintaining wakefulness.We found that chronic HFD impaired the activity of PVT neurons.Notably,inactivation of the PVT was sufficient to reduce and fragment wakefulness during the active phase in lean mice,similar to the sleep-wake alterations observed in obese mice with HFD-induced obesity.On the other hand,enhancing PVT neuronal activity cons olidated wakefulness in mice with HFD-induced obesity.We observed that the fragmented wakefulness could be eliminated and reversed by TRF.Furthermore,TRF prevented the HFD-induced disruptions on synaptic transmission in the PVT,in a feeding duration-dependent manner.Collectively,our findings demonstrate that ad libitum access to a HFD results in inactivation of the PVT,which is critical to impaired nocturnal wakefulness and increased sleep,while TRF can prevent and reverse diet-induced PVT dysfunction and excessive sleepiness.We establish a link between TRF and neural activity,through which TRF can potentially serve as a lifestyle intervention against diet/obesity-related ED S.

关键词： high-fat diet excessive daytime sleepiness sleep–wake cycle fragmented wakefulness paraventricular thalamic nucleus time-restricted feeding

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Estimating heat capacities of liquid organic compounds based on elements and chemical bonds contribution

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Chinese Journal of Chemical Engineering 2023年第5期57卷 30-38页

作者： Li Xia Yule Pan Tingting Zhao Xiaoyan Sun Shaohui tao Yushi chen Shuguang xiang Institute of Process System Engineering College of Chemical EngineeringQingdao University of Science and TechnologyQingdao 266042China Petro-Cyber Works Information Technology Company Limited Shanghai Branch Shanghai 200120China

Molecular property depends on the property, the number of the elements, and the interaction between elements(such as chemical bonds). Based on the above-mentioned idea, two methods to estimate the isobaric heat capacity of liquids organic compounds were developed. Ten elements groups and 32 chemical bond groups were defined by considering the structure of organic compounds. The group contribution values and correlation parameters were regressed by the ridge regression method with the experiment data of 1137 compounds. The heat capacity can be calculated by summating the contributions of the elements and chemical bond groups. The two methods were compared with existing group contribution methods, such as Chickos, Zabransky-Ruzicka, and Zdenka Kolska. The results show that those new estimation methods' overall average relative deviations were 5.81% and 5.71%, which were lower than the other three methods. Those methods were more straightforward in compound splitting.Those new methods can be used to estimate the liquid heat capacity of silicon-containing compounds,which the other three methods cannot estimate. The new methods are more accessible, broader, and more accurate. Therefore, this research has important scientific significance and vast application prospects.

关键词： Thermodynamic Properties Model Prediction Elements and Chemical Bonds

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Practical cloud storage auditing using serverless computing

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Science China(Information Sciences) 2023年

作者： Fei chen Jianquan CAI tao xiang Xiaofeng LIAO College of Computer Science and Software Engineering Shenzhen University College of Computer Science Chongqing University

Cloud storage auditing research is dedicated to solving the data integrity problem of outsourced storage on the cloud. In recent years, researchers have proposed various cloud storage auditing schemes using different techniques. While these studies are elegant in theory, they assume an ideal cloud storage model;that is, they assume that the cloud provides the storage and compute interfaces as required by the proposed schemes. However, this does not hold for mainstream cloud storage systems because these systems only provide read and write interfaces but not the compute interface. To bridge this gap, this work proposes a serverless computing-based cloud storage auditing system for existing mainstream cloud object storage. The proposed system leverages existing cloud storage auditing schemes as a basic building block and makes two adaptations. One is that we use the read interface of cloud object storage to support block data requests in a traditional cloud storage auditing scheme. Another is that we employ the serverless computing paradigm to support block data computation as traditionally required. Leveraging the characteristics of serverless computing, the proposed system realizes economical, pay-as-you-go cloud storage auditing. The proposed system also supports mainstream cloud storage upper layer applications(e.g., file preview) by not modifying the data formats when embedding authentication tags for later auditing. We prototyped and open-sourced the proposed system to a mainstream cloud service, i.e., Tencent Cloud. Experimental results show that the proposed system is efficient and promising for practical use. For 40 GB of data, auditing takes approximately98 s using serverless computation. The economic cost is 120.48 CNY per year, of which serverless computing only accounts for 46%. In contrast, no existing studies reported cloud storage auditing results for real-world cloud services.

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Synergistic Effect and Fluorination Effect in Ethylene Polymerization by Nickel Phenoxyiminato Catalysts

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Chinese Journal of Polymer Science 2018年第2期36卷 244-251页

作者： Di Xu xiang-xiang Zhao Zhong-tao chen Yu-Guo Ma Beijing National Laboratory for Molecular Sciences (BNLMS) Center for Soft Matter Science and Engineering Key Lab of Polymer Chemistry & Physics of Ministry of Education College of Chemistry Peking University

A series of binuclear nickel phenoxyiminato catalysts with different linkers and fluorine substituents were efficiently synthesized. Binuclear nickel catalysts with rigid linkers showed higher catalytic activity and thermal stability in ethylene polymerization and produced polymers with higher molecular weight possibly due to the larger steric hindrance and metal-metal synergistic effect. The introduction of fluorine atoms on the N-terphenyl moity also enhanced polymerization activity and molecular weight of polymer due to the electronic effect of fluorine atoms.

关键词： Nickel phenoxyiminato catalysts Fluorination effect Synergistic effect Bimetallic catalysts

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Prediction of ground settlements induced by twin shield tunnelling in rock and soil--A case study

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Underground Space 2022年第4期7卷 623-635页

作者： Xue-tao Wang Thomas von Schmettow xiang-sheng chen Chang-qing Xia College of Civil and Transportation Engineering Shenzhen University518060 ShenzhenChina Underground Polis Academy Shenzhen University518060 ShenzhenChina Key Laboratory of Coastal Urban Resilient Infrastructures(MOE) Shenzhen University518060 ShenzhenChina Tunnels Engineering Zentrale TechnikEd.Zu¨blinStuttgart 70567Germany

Ground movements caused by the construction of tunnels and excavation are inevitable.Estimation of such movements is a very important for risk management in tunnel design.This paper presents a case study of ground settlements induced by twin shield tunnelling in Copenhagen using analytical and numerical methods and their predictions.The predictions are compared with the monitored settlements.The comparison shows that the predictions are sufficiently conservative.

关键词： Shield tunneling Greenfield settlement Empirical method Analytical method FEM

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BYPASS1-LIKE regulates lateral root initiation via exocytic vesicular trafficking-mediated PIN recycling in Arabidopsis

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Journal of Integrative Plant Biology 2022年第5期64卷 965-978页

作者： Gang Yang Bi-Xia chen tao chen Jia-Hui chen xiang-Yu Lin Xiu-Le Yue Li-Zhe An Hua Zhang Key Laboratory of Cell Activities and Stress Adaptations Ministry of EducationSchool of Life SciencesLanzhou UniversityLanzhou 730000China College of Life Science and Technology Gansu Agricultural UniversityLanzhou 730070China School of Forestry Beijing Forestry UniversityBeijing 100083China

Auxin and auxin-mediated signaling pathways are known to regulate lateral root development.Although exocytic vesicle trafficking plays an important role in recycling the PIN-FORMED(PIN)auxin efflux carriers and in polar auxin transport during lateral root formation,the mechanistic details of these processes are not well understood.Here,we demonstrate that BYPASS1-LIKE(B1 L)regulates lateral root initiation via exocytic vesicular trafficking-mediated PIN recycling in Arabidopsis thaliana.b1 l mutants contained significantly more lateral roots than the wild type,primarily due to increased lateral root primordium initiation.Furthermore,the auxin signal was stronger in stage I lateral root primordia of b1 l than in those of the wild type.Treatment with exogenous auxin and an auxin transport inhibitor indicated that the lateral root phenotype of b1 l could be attributed to higher auxin levels and that B1 L regulates auxin efflux.Indeed,compared to the wild type,C-terminally green fluorescent protein-tagged PIN1 and PIN3 accumulated at higher levels in b1 l lateral root primordia.B1 L interacted with the exocyst,and b1 l showed defective PIN exocytosis.These observations indicate that B1 L interacts with the exocyst to regulate PIN-mediated polar auxin transport and lateral root initiation in Arabidopsis.

关键词： B1L exocytic vesicular trafficking lateral root PIN recycling

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