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改善不同地应力下隧道轮廓爆破成型效果

Journal of Central South University 2024年第3期31卷 930-949页

作者：周子龙王培宇程瑞山陈翠刚蔡鑫 School of Resources and Safety Engineering Central South UniversityChangsha 410083China Center for Infrastructural Monitoring and Protection School of Civil and Mechanical EngineeringCurtin UniversityBentley 6102Australia

含预切空腔的轮廓爆破技术被认为是改善高地应力下隧道轮廓成型的有效方法。然而,对这种爆破技术在不同地应力下性能的研究较少。本文通过校验后的公路隧道数值模型,调查了含预切空腔(PC)的两种典型轮廓爆破技术(即光面爆破(SB)和预裂爆... 详细信息

含预切空腔的轮廓爆破技术被认为是改善高地应力下隧道轮廓成型的有效方法。然而,对这种爆破技术在不同地应力下性能的研究较少。本文通过校验后的公路隧道数值模型,调查了含预切空腔(PC)的两种典型轮廓爆破技术(即光面爆破(SB)和预裂爆破(PB))在不同地应力条件下的性能。结果表明,在耦合装药和50 MP地应力下,PCSB比PCPB能获得更好的隧道轮廓成型效果。此外,研究了两种轮廓爆破技术在不同的不耦合系数和地应力条件下的性能,发现随着地应力从30 MPa增加至50 MPa,PCSB和PCPB作用下隧道轮廓成型效果均逐渐改善。此外,在不同地应力条件下调整周边孔的不耦合系数能使PCPB形成有效的隧道轮廓。然而,对于PCSB,在不同地应力条件下,需调整所有炮孔的不耦合系数才能形成符合要求的隧道轮廓。最后通过多元非线性回归获得经验公式,本研究可以为不同地应力下使用PCSB和PCPB开挖隧道提供设计参考。

关键词：地应力光面爆破预裂爆破隧道轮廓成型不耦合系数

Learning layout generation for virtual worlds

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Computational Visual Media 2024年第3期10卷 577-592页

作者： Weihao cheng Ying shan ARC Lab TencentShenzhen 518057China

The emergence of the metaverse has ledto the rapidly increasing demand for the generation ofextensive 3D worlds. We consider that an engagingworld is built upon a rational layout of multiple landuse areas (e.g., forest, meadow, and farmland). Tothis end, we propose a generative model of landuse distribution that learns from geographic *** model is based on a transformer architecturethat generates a 2D map of the land-use layout,which can be conditioned on spatial and semanticcontrols, depending on whether either one or bothare provided. This model enables diverse layoutgeneration with user control and layout expansion byextending borders with partial inputs. To generatehigh-quality and satisfactory layouts, we devise ageometric objective function that supervises the modelto perceive layout shapes and regularize generationsusing geometric priors. Additionally, we devise aplanning objective function that supervises the modelto perceive progressive composition demands andsuppress generations deviating from controls. Toevaluate the spatial distribution of the generations, wetrain an autoencoder to embed land-use layouts intovectors to enable comparison between the real andgenerated data using the Wasserstein metric, which isinspired by the Fr´echet inception distance.

关键词： layout generation virtual worlds Transformer land-use

Ternary superhydrides for high-temperature superconductivity at low pressures

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National Science Review 2024年第7期11卷 12-14页

作者： Pengfei shan Liang Ma Jinguang cheng Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences School of Physical Sciences University of Chinese Academy of Sciences Key Laboratory of Materials Physics Ministry of Education School of Physics and Microelectronics Zhengzhou University

The quest for room-temperature superconductivity(RTSC) has been a longstanding pursuit in physics since the discovery of superconductivity in *** to the conventional Bardeen-Cooper-Schrieffer theory, atomic metallic hydrogen holds great promise for achieving this goal due to its high Debye temperature and strong electron-phonon coupling.

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Self-initiated static-dynamic state transition behavior and triggering mechanism of strain rockburst using three-dimensional discrete element method

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Underground Space 2024年第3期16卷 143-163页

作者： Yuan Qian cheng Zhao rui Wei rui Zhang Lin Huang Huiguan Chen Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education Tongji UniversityShanghai 200092China School of Engineering Tibet UniversityLhasaTibet850000China

The accurate understanding of rockburst mechanism poses a global challenge in the field of rock *** for strain rockburst,achieving self-initiated static-dynamic state transition is a crucial step in the formation of catastrophic ***,the state transition behavior and its impact on rockburst have not received sufficient attention,and are still poorly ***,this study specifically focuses on the state transition behavior,aiming to investigate its abrupt transition process and formation mechanism,and triggering effects on *** facilitate the study,a novel burst rock-surrounding rock combined laboratory test model is proposed and its effectiveness is validated through experiment ***,corresponding numerical models are established using the three-dimensional(3D)discrete element method(DEM),enabling successful simulation of static brittle failure and rockbursts of varying intensities under quasi-static displacement loading ***,through secondary development,comprehensive recording of the mechanical and energy information pertaining to the combined specimen system and its subsystems is *** a result of numerical investigation studies,the elastic rebound dynamic behavior of the surrounding rock was discovered and identified as the key factor triggering rockburst and controlling its *** impact loading on the burst rock,induced by elastic rebound,directly initiates the dynamic processes of rockburst,serving as the direct ***,the transient work and energy convergence towards the burst rock resulting from elastic rebound are recognized as the inherent cause of ***,it has been observed that a larger extent of surrounding rock leads to a stronger elastic rebound,thereby directly contributing to a more intense *** findings can provide novel theoretical insights for the exploring of rockburst mechanism and the development of monitoring and

关键词： Strain rockburst Static-dynamic state transition Self-initiation Triggering mechanism Elastic rebound Discrete element method

Thyristor-inserted MMC Sub-module Topology with DC Fault Blocking Capability

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CSEE Journal of Power and Energy Systems 2024年第5期10卷 2221-2229页

作者： cheng Peng rui Li Xu Cai Key Laboratory of Control of Power Transmission and Conversion Shanghai Jiao Tong UniversityMinistry of EducationShanghai Jiao Tong UniversityShanghai 200240China.

Modular multilevel converter(MMC)is increasingly being applied to high voltage direct current(HVDC)***,dc short circuit situations restrain the application of a conventional half bridge MMC *** this paper,a new sub-module topology with inserted thyristor can help the MMC system clear a dc side *** states and devices voltage stress of the proposed topology are analyzed and the conduction loss comparison between the proposed topology with several existing topologies with dc fault blocking capability is carried *** show the proposed topology is superior to other topologies in terms of conduction loss while using the same voltage rating ***,compared with traditional half bridge topology,only thyristors and diodes are added in the proposed ***,cost of the proposed topology can be lower than conventional hybrid MMC *** last,the fault blocking capability of the proposed topology is verified in the simulation.

关键词： Fault current limiting high voltage direct current(HVDC)transmission modular multilevel converter(MMC)

Facet effects on bimetallic ZnSn hydroxide microcrystals for selective electrochemical CO2 reduction

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Green Energy & Environment 2024年第8期9卷 1314-1320页

作者： Liu Han cheng-wei Wang shan-shan Luo Ying-tang Zhou Bing Li Ming Liu School of Chemistry and Chemical Engineering Harbin Institute of Technology National Engineering Research Center for Marine Aquaculture Marine Science and Technology CollegeZhejiang Ocean University

Employing crystal facets to regulate the catalytic properties in electrocatalytic carbon dioxide reduction reaction（eCO2RR） has been well demonstrated on electrocatalysts containing single metals but rarely explored for bimetallic systems. Here, we synthesize Zn Sn（OH）6（ZSO）microcrystals（MCs） with distinct facets and investigate the facet effects in eCO2RR. Electrochemical studies and in situ Fourier Transform Infrared Spectroscopy（in situ-FTIR） reveal that ZSO MCs produce mainly C1 products of HCOOH and CO. The {111} facet of the ZSO MCS exhibits higher selectivity and faradaic efficiency（FE） than that of the {100} facet over a wide range of potentials（-0.9 V ～-1.3 V versus RHE）. Density Functional Theory（DFT） calculations elucidate that the {111} facet is favorable to the adsorption/activation of CO2molecules,the formation of intermediate in the rate-determining step, and the desorption of C1 products of CO and HCOOH molecules.

关键词： ZnSn(OH) 6 Crystal facets Electrochemical carbon dioxide reduction C1 product Density functional theory

An improved joint method for onset picking of acoustic emission signals with noise

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Journal of Central South University 2019年第10期26卷 2878-2890页

作者： ZHOU Zi-long cheng rui-shan CHEN Lian-jun ZHOU Jing CAI Xin Faculty of Mining Engineering School of Resources and Safety EngineeringCentral South UniversityChangsha 410083China State Key Laboratory of Mining Disaster Prevention and Control Shandong University of Science and TechnologyQingdao 266590China

The onset times of acoustic signals with spikes,heavy bodies and unclear takeoffs are difficult to be picked accurately by the automatic method at *** deal with this problem,an improved joint method based on the discrete wavelet transform(DWT),modified energy ratio(MER)and Akaike information criterion(AIC)pickers,has been proposed in this ***,the DWT is used to decompose the signal into various ***,the joint application of MER and AIC pickers is carried out to pick the initial onset times of all selected components,where the minimum AIC position ahead of MER onset time is regarded as the initial onset ***,the average for initial onset times of all selected components is calculated as the final onset time of this *** improved joint method is tested and validated by the acoustic signals with different signal to noise ratios(SNRs)and *** results show that the improved joint method is not affected by the variations of SNR,and the onset times picked by this method are always accurate in different ***,the onset times of all acoustic signals with spikes,heavy bodies and unclear takeoffs can be accurately picked by the improved joint *** to some other methods including MER,AIC,DWT-MER and DWT-AIC,the improved joint method has better SNR stabilities and waveform adaptabilities.

关键词： Akaike information criterion(AIC) modified energy ratio(MER) discrete wavelet transform(DWT) acoustic signals with noise

Facile synthesis of high-brightness green-emitting carbon dots with narrow bandwidth towards backlight display

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Chinese Chemical Letters 2024年第5期35卷 277-282页

作者： rui cheng Tingting Zhang Xin Huang Jian Yu State Key Laboratory of Materials-Oriented Chemical Engineering College of Chemical EngineeringNanjing Tech UniversityNanjing 210009China

High-performance carbon dots(CDs)allowing the application in high-end display devices are highly desirable and usually limited by the absence of simple and easy synthesis *** this work,we exploited an easy-to-implement strategy for the one-step synthesis of green-emitting CDs(G-CDs)with superb optical *** G-CDs were synthesized using m-phenylenediamine(m-PD)as a single precursor,and the reaction reacted at 180℃for 12 h The resultant G-CDs exhibit high-purity and excitationindependent green fluorescence with the photoluminescence(PL)peak located at 516 nm,full width at half maximum(FWHM)of 46 nm,and PL quantum yield(QY)of∼80%under the 470nm excitation *** G-CDs and corresponding composite film prepared with polyvinyl butyral(G-CDs@PVB)exhibit good PL stability after undergoing long-time storage for one year and 360 h exposure under 460nm blue *** G-CDs@PVB film was used as color-conversion materials in green-emitting light-emitting diode(LED)application,exhibiting a Commission internationale de l’Eclairage(CIE)chromaticity coordinate of(0.21,0.44).The film was also used in CD-based liquid crystal display(CD-LCD)application,achieving a color gamut value of 85%.This work will offer a working basis for the synthesis of high-performance CDs as well as their application in displays.

关键词： Carbon dots One-step synthesis Narrow bandwidth High quantum yield Display

Evolving molecular subtyping of breast cancer advances precision treatment

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Cancer Biology & Medicine 2024年第9期21卷 731-739页

作者： rui shan Lei-Jie Dai Zhi-Ming Shao Yi-Zhou Jiang Department of Breast Surgery Fudan University Shanghai Cancer CenterShanghai 200032China Department of Oncology Shanghai Medical CollegeFudan UniversityShanghai 200032China

Breast cancer is the second most prevalent cancer *** 2022,approximately 2.3 million newly diagnosed cases of female breast cancer occurred worldwide,and more than 665 thousand people lost their lives to this disease^... 详细信息

关键词： breast cancer Breast