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Dynamic impact properties of deep sandstone under thermal-hydraulicmechanical coupling loads

Journal of Mountain Science 2024年第6期21卷 2113-2129页

作者： CAO Chunhui DING Haonan zou Baoping School of Civil Engineering and Architecture Zhejiang University of Science and TechnologyHangzhou 310023China Zhejiang-Singapore Joint Laboratory for Urban Renewal and Future City Hangzhou 310023China

The deep rock mass within coal mines situated in a challenging environment are characterized by high ground stress,high geotemperature,high osmotic water pressure,and dynamic disturbances from mechanical *** investigate the impact of this complex mechanical environment on the dynamic characteristics of roof sandstone in self-formed roadways without coal pillars,standard specimens of deep sandstone from the 2611 upper tunnel working face of the Yongmei Company within the Henan Coal Chemical Industry Group in Henan,China were prepared,and an orthogonal test was *** a self-developed geotechnical dynamic impact mechanics test system,triaxial dynamic impact tests under thermal-hydraulicmechanical coupling conditions were conducted on deep *** results indicate that under high confining pressure,deep sandstone exhibits pronounced brittle failure at low temperatures,with peak strength gradually decreasing as temperature and osmotic water pressure ***,under low confining pressure and low temperature,the brittleness of deep sandstone weakens gradually,while ductility ***,sandstone demonstrates higher peak strength at low temperatures under high axial pressure conditions,lower peak strength at high temperatures,and greater strain under low axial pressure and high osmotic water *** in impact air pressure and osmotic water pressure have proportionally greater effects on peak stress and peak *** 50%of the input strain energy is utilized as effective energy driving the sandstone fracture *** analysis identifies the optimal combination of factors affecting the peak stress and peak strain of *** the coupling effect,intergranular and transgranular fractures occur within the *** images illustrate that the damage forms range from minor damage with multiple fissures to extensive fractures and severe *** study elucidates the varied dynamic impact me

关键词： Deep sandstone Thermal-hydraulicmechanical coupling Dynamic impact Stress-strain Failure Modes Polar analysis

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Vertical two-dimensional WS_(2)flakes grown on flexible CNT film for excellent electrochemical performance

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Rare Metals 2024年第1期43卷 164-174页

作者： Qian Gong Jing-Yun zou Ming Ren Si-Qi Zhu Yu-Rong Zhou Li-Ming Zhao Jian Chen Yu-Long Wu Jiang-Tao Di Li-Xing Kang qing-Wen Li School of Nano-Tech and Nano-Bionics University of Science and Technology of ChinaHefei 230026China Key Laboratory of Multifunctional Nanomaterials and Smart Systems Division of Advanced MaterialsSuzhou Institute of Nano-Tech and Nano-BionicsChinese Academy of SciencesSuzhou 215123China Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application School of Physical Science and TechnologySuzhou University of Science and TechnologySuzhou 215009China

Soft electrochemical actuators that can generate mechanical motions in response to electrical stimuli can be used as artificial muscles in microscale *** electrode materials are the key component of the electrochemical actuator because they limit the ion diffusion and accumulation processes and thus affect the deformation in fast response-time and potential engineering ***-dimensional materials,such as one-dimensional(1D)CNT and two-dimensional(2D)vertically stood WS_(2),are great electrode due to their good electrochemical stability and high surface-to-volume ratios,but show limited performances when being used on their own in the actuators because of low reconstruction or low conductivity.A combination of 1D CNT and 2D WS_(2)could form a heterojunction with both high electrochemical activity and great mechanical ***,by depositing highly disordered graphene nanosheets(HDGNs)on CNT films and then WS_(2)on the formed low-dimensional nanocarbon film,a hybrid WS_(2)/HDGN/CNT film was synthesized through a multistep CVD *** grown WS_(2)nanosheets were achieved by taking advantage of HDGNs which limits CNTs ***,the volume expansion caused by the transition from WO_(3)to WS-2can force the vertical growth of WS_(2).This hybrid film shows excellent electrochemical properties,such as high specific capacitance and high rate *** actuators based on the WS_(2)/HDGN/CNT films show good actuating performance,including stability and reconfigurability.

关键词： CNT Graphene Vertically growth WS_(2) Electrochemical actuators

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Highly Efficient Aligned Ion‑Conducting Network and Interface Chemistries for Depolarized All‑Solid‑State Lithium Metal Batteries

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Nano-Micro Letters 2024年第5期16卷 102-119页

作者： Yongbiao Mu Shixiang Yu Yuzhu Chen Youqi Chu Buke Wu qing Zhang Binbin Guo Lingfeng zou Ruijie Zhang Fenghua Yu Meisheng Han Meng Lin Jinglei Yang Jiaming Bai Lin Zeng Shenzhen Key Laboratory of Advanced Energy Storage Southern University of Science and TechnologyShenzhen 518055People’s Republic of China Department of Mechanical and Energy Engineering Southern University of Science and TechnologyShenzhen 518055People’s Republic of China SUSTech Energy Institute for Carbon Neutrality Southern University of Science and TechnologyShenzhen 518055People’s Republic of China Department of Mechanical and Aerospace Engineering Hong Kong University of Science and TechnologyKowloon 997077Hong Kong Special Administrative Region of ChinaPeople’s Republic of China HKUST Shenzhen-Hong Kong Collaborative Innovation Research Institute FutianShenzhenPeople’s Republic of China

Improving the long-term cycling stability and energy density of all-solid-state lithium(Li)-metal batteries(ASSLMBs)at room temperature is a severe challenge because of the notorious solid–solid interfacial contact loss and sluggish ion *** electrolytes are generally studied as two-dimensional(2D)structures with planar interfaces,showing limited interfacial contact and further resulting in unstable Li/electrolyte and cathode/electrolyte ***,three-dimensional(3D)architecturally designed composite solid electrolytes are developed with independently controlled structural factors using 3D printing processing and post-curing ***-type electrolyte films with vertical-aligned micro-pillar(p-3DSE)and spiral(s-3DSE)structures are rationally designed and developed,which can be employed for both Li metal anode and cathode in terms of accelerating the Li+transport within electrodes and reinforcing the interfacial *** printed p-3DSE delivers robust long-term cycle life of up to 2600 cycles and a high critical current density of 1.92 mA cm^(−2).The optimized electrolyte structure could lead to ASSLMBs with a superior full-cell areal capacity of 2.75 mAh cm^(−2)(LFP)and 3.92 mAh cm^(−2)(NCM811).This unique design provides enhancements for both anode and cathode electrodes,thereby alleviating interfacial degradation induced by dendrite growth and contact *** approach in this study opens a new design strategy for advanced composite solid polymer electrolytes in ASSLMBs operating under high rates/capacities and room temperature.

关键词： All-solid-state lithium metal batteries Composite solid electrolyte 3D printing Areal capacity Interfacial degradation

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Jackknife Model Averaging for Composite Quantile Regression

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Journal of Systems Science & Complexity 2024年第4期37卷 1604-1637页

作者： YOU Kang WANG Miaomiao zou Guohua School of Mathematical Sciences Capital Normal UniversityBeijing 100089China School of Chinese Materia Medica Beijing University of Chinese MedicineBeijing 100105China

In this paper,the authors propose a frequentist model averaging method for composite quantile regression with diverging number of *** from the traditional model averaging for quantile regression which considers only a single quantile,the proposed model averaging estimator is based on multiple *** well-known delete-one cross-validation or jackknife approach is applied to estimate the model *** resultant jackknife model averaging estimator is shown to be asymptotically optimal in terms of minimizing the out-of-sample composite final prediction *** studies are conducted to demonstrate the finite sample performance of the new model averaging *** proposed method is also applied to the analysis of the stock returns data and the wage data.

关键词： Asymptotic optimality composite quantile regression cross-validation model averaging

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On-Chip Sub-Picometer Continuous Wavelength Fiber-Bragg-Grating Interrogator

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Photonic Sensors 2024年第1期14卷 73-84页

作者： Yuan ZHUANG Jun zou Jiqiang ZHANG Lu ZHANG Jiahe ZHANG Leixin MENG qing YANG Research Center for Humanoid Sensing Zhejiang LabHangzhou 311121China ZJU-Hangzhou Global Scientific and Technological Innovation Center Hangzhou 310014China State Key Laboratory of Modern Optical Instrumentation College of Optical Science and EngineeringInternational Research Center for Advanced PhotonicsZhejiang UniversityHangzhou 310058China

Miniaturized fiber-Bragg-grating(FBG)interrogators are of interest for applications in the areas where weight and size controlling is important,e.g.,airplanes and aerospace or in-situ *** ultra-compact high-precision on-chip interrogator is proposed based on a tailored arrayed waveguide grating(AWG)on a silicon-on-insulator(SOI)*** on-chip interrogator enables continuous wavelength interrogation from 1544 nm to 1568 nm with the wavelength accuracy of less than 1 pm[the root-mean-square error(RMSE)is 0.73 pm]over the whole wavelength *** chip loss is less than 5 *** 1×16 AWG is optimized to achieve a large bandwidth and a low noise level at each channel,and the FBG reflection peaks can be detected by multiple output channels of the *** fabricated AWG is utilized to interrogate FBG sensors through the center of gravity(CoG)*** validation of an on-chip FBG interrogator that works with sub-picometer wavelength accuracy in a broad wavelength range shows large potential for applications in miniaturized fiber optic sensing systems.

关键词： Fiber optic sensing on-chip interrogator arrayed waveguide grating center of gravity

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Explaining the dynamics of the sub-relativistic electron third belt in the Earth's radiation belts by using medium Earth orbit satellite observations

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Earth and Planetary Physics 2024年第5期8卷 762-775页

作者： JiaLi Chen Hong zou YuGuang Ye Institute of Space Physics and Applied Technology Peking University

The Earth's electron radiation belts typically exhibit a two-belt structure. However, observations from the Van Allen Probes revealed the existence of a three-belt structure. This structure consists of an inner belt, a slot region, a remnant belt, a “second slot,” and a new outer belt(or the “third belt”). The formation of the structure involves both the partial loss of the original outer belts and the formation of the third belts. These processes are likely associated with radial diffusion induced by ultra-low-frequency(ULF) waves. In this study, we mainly analyzed electron flux data from medium Earth orbit(MEO) navigation satellites M17–M19 to supplement the observational evidence for the sub-relativistic electron(～100–500 keV) three-belt structure. Evidence of substorm injections and ULF waves during the three-belt event was identified, suggesting they played significant roles in the formation and evolution of the third *** injections may introduce new electron populations to the third belt, whereas ULF waves may influence the evolution of the third belt through radial diffusion. Toward the end of the three-belt event, the compression of the magnetosphere by shocks may lead to the dropout of the third belt because of the magnetopause shadowing effect and outward radial diffusion, ultimately disrupting the three-belt structure. This study provides more evidence for the presence of a sub-relativistic electron three-belt structure and offers an analysis of the evolutionary mechanisms of the third belt, which may contribute to a comprehensive understanding of the electron three-belt structure in the radiation belts.

关键词： third belt sub-relativistic electrons three-belt structure radiation belts magnetic storms and substorms wave–particle interactions

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Nonlinear uncertainty impact of geometric variations on aerodynamic performance of low-pressure turbine blades with ultra-high loading under extreme operational conditions

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Chinese Journal of Aeronautics 2024年第5期37卷 281-300页

作者： Xiaojing WANG Zhengping zou Chao FU Pengcheng DU School of Energy and Power Engineering Beihang UniversityBeijing 100191China National Key Laboratory of Science and Technology on Aero-Engine Aero-Thermodynamics Beihang UniversityBeijing 100191China Research Institute of Aero-Engine Beihang UniversityBeijing 100191China

Uncertainty impact of random geometric variations on the aerodynamic performance of low-pressure turbine blades is considerable,which is further amplified by the current ultra-high-lift design trend for weight ***,this uncertainty impact on ultra-highly loaded blades under extreme operational conditions near the margins with potential large-scale open separation is focused on in this *** is demonstrated that this impact is significant,unfavourable,and nonlinear,which is clearly severer under extreme *** addition to the overall attenuation and notable scattering of specific performance,the operational margins with open separation are also notably scattered with great risk of significant *** scattering and nonlinearity are dominated by the variations in leading-edge *** thinning of leading edge triggers local transition,enhancing downstream friction and reducing resistance to open separation,which is further exacerbated by operational ***,the opposite thickening yields less benefit,implying *** unfavourable impact highlights the need for robust aerodynamic design,where both a safer operational condition and a more robust blade are indispensable,i.e.,a compromise among performance,weight,and *** the necessary limitation of loading levels,a mid-loaded design is recommended to reduce adverse pressure gradients in both the leading edge and rear region of the suction side,which helps to decrease the susceptibility of the transition and open separation to random *** improvements can also be achieved by appropriately thickening the leading edge.

关键词： Ultra-highly loaded turbine blade Geometric variations Uncertainty analysis Operational margins Robust aerodynamic design Nonlinearity

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Covariate-Assisted Matrix Completion with Multiple Structural Breaks

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Journal of Systems Science & Complexity 2024年第2期37卷 692-728页

作者： MENG Jing FENG Long zou Changliang WANG Zhaojun School of Statistics and Data Science KLMDASRLEBPSand LPMCNankai UniversityTianjin 300071China

In matrix completion,additional covariates often provide valuable information for completing the unobserved entries of a high-dimensional low-rank matrix *** this paper,the authors consider the matrix recovery problem when there are multiple structural breaks in the coefficient matrix β under the column-space-decomposition model A=Xβ+B.A cumulative sum(CUSUM)statistic is constructed based on the penalized estimation of β.Then the CUSUM is incorporated into the Wild Binary Segmentation(WBS)algorithm to consistently estimate the location of ***,a nearly-optimal recovery of A is *** findings are further corroborated via numerical experiments and a real-data application.

关键词： Additional covariates matrix completion multiple structural breaks wild Binary Segmentation

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Brain Cognition Mechanism-Inspired Hierarchical Navigation Method for Mobile Robots

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Journal of Bionic Engineering 2024年第2期21卷 852-865页

作者： Qiang zou Chengdong Wu Ming Cong Dong Liu Faculty of Robot Science and Engineering Northeastern UniversityShenyang110819China School of Mechanical Engineering Dalian University of TechnologyDalian116024China

Autonomous navigation is a fundamental problem in *** methods generally build point cloud map or dense feature map in perceptual space;due to lack of cognition and memory formation mechanism,traditional methods exist poor robustness and low cognitive *** a new navigation technology that draws inspiration from mammal’s navigation,bionic navigation method can map perceptual information into cognitive space,and have strong autonomy and environment *** improve the robot’s autonomous navigation ability,this paper proposes a cognitive map-based hierarchical navigation ***,the mammals’navigation-related grid cells and head direction cells are modeled to provide the robots with location *** then a global path planning strategy based on cognitive map is proposed,which can anticipate one preferred global path to the target with high efficiency and short ***,a hierarchical motion controlling method is proposed,with which the target navigation can be divided into several sub-target navigation,and the mobile robot can reach to these sub-targets with high confidence ***,some experiments are implemented,the results show that the proposed path planning method can avoid passing through obstacles and obtain one preferred global path to the target with high efficiency,and the time cost does not increase extremely with the increase of experience nodes *** motion controlling results show that the mobile robot can arrive at the target successfully only depending on its self-motion information,which is an effective attempt and reflects strong bionic properties.

关键词： Bionic navigation Spatial localization cells Global path planning Hierarchical motion controlling

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Different concentrations of hyaluronic acid eye drops for dry eye syndrome: a systematic review and Meta-analysis

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International Journal of Ophthalmology(English edition) 2024年第6期17卷 1110-1119页

作者： Xiao-Wei Ouyang Sheng Fang Yun-Min Yi Shi-Peng zou Qi-Yu Hu Zi-Xuan Huang qing-Xia Li Jin-Yan Luo Department of Ophthalmology Nanchang Hongdu Hospital of Traditional Chinese MedicineNanchang 330000Jiangxi ProvinceChina Department of Ophthalmology Jiangxi Hospital of Integrated Traditional Chinese and Western MedicineNanchang 330000Jiangxi ProvinceChina Department of Cataract Nanchang University Affiliated Eye HospitalNanchang 330000Jiangxi ProvinceChina Department of Neuro-ophthalmology Nanchang University Affiliated Eye HospitalNanchang 330000Jiangxi ProvinceChina

AIM:To compare high or low concentration of hyaluronic acid eye drops(HY)for dry eye syndromes(DES).METHODS:Randomized controlled trials(RCTs)comparing various concentrations of HY were searched in PubMed,Embase,Web of Science,Cochrane,SinoMed,CNKI,Wanfang Database,CQVIP,and Chinese journals databases between inception and July *** standardized mean differences(SMD)or weighted mean difference(WMD)with 95%confidence intervals(CI)from RCTs evaluating Schirmer’s I test(SIT),corneal fluorescein staining score(CFS),tear breakup time(TBUT),DES score(DESS),and Ocular Surface Disease Index(OSDI)were *** analysis,Egger’s test and Meta-regression analysis were performed for all ***:We conducted a Meta-analysis of 10 RCTs that met the inclusion criteria,involving 1796 ***-concentrations group significantly improved the outcome of CFS according to random effects modelling(SMD,-3.37;95%CI,-5.25 to-1.48;P=0.0005).The rest of the results were not statistically significant,including indicators such as SIT,TBUT,DESS and ***:For dry eyes with positive corneal staining,a high concentration of HY is recommended,whereas in other cases,a high concentration of HY does not offer a more pronounced advantage over a low concentration of HY in the treatment of dry eyes.

关键词： dry eye hyaluronic acid concentration Meta-analysis

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