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Numerical simulation and analysis of drill rods vibration during roof bolt hole drilling in underground mines

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International Journal of Mining Science and Technology 2018年第6期28卷 877-884页

作者： Shaowei Liu Mengxiong Fu Housheng jia Wenbin Li Yafei luo School of Energy Science and Engineering Henan Polytechnic UniversityJiaozuo 454000China The Safety of Coal Production Collaborative Innovation Center Jiaozuo 454000China

Structural deterioration in the roof in an underground mine can easily cause roof fall, and deterioration is difficult to detect. When drilling holes for roof bolts, there is a relationship between the vibration of the drill rod and the properties of the rock being drilled. This paper analyzes transverse, longitudinal, and torsional vibrations in the drill rod by using vibration theory. Characteristic indexes for three kinds of vibration are determined. Using the finite element analysis software ABAQUS, a model for drill rod vibration during the drilling of roof bolt holes was established based on the geological and mining conditions in the Guyuan Coal Mine, northern China. Results from the model determined that the transverse and the longitudinal vibration decrease as the rock hardness decreases. In descending order, sandstone,sandy mudstone, mudstone, and weak interbeds cause progressively less vibration when being *** ranking for strata that cause decreasing torsional vibration is slightly different, being, in descending order, mudstone, sandstone, sandy mudstone, and weak interbeds. These results provide a theoretical basis for predicting dangerous roof conditions and the presence of weak interbeds to allow for adjusting bolt support schemes.

关键词： Roof bolt holedrilling Drill rod vibration Vibration radius Vibration point amplitude Negative angular acceleration

Simulation and Analysis of Crashworthiness of Fuel Tank for Helicopters

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Chinese Journal of Aeronautics 2007年第3期20卷 230-235页

作者： luo Cheng LIU Hua YANG jia-ling LIU Kai-xin Institute of Solid Mechanics Beijing University of Aeronautics and Astronautics Beijing 100083 China Department of Mechanics and Engineering Peking University Beijing 100871 China

Crashworthiness requirement of fuel tanks is one of the important requirements in helicopter designs. The relations among the protection frame, textile layer and rubber layer of the fuel tank are introduced. Two appropriate FE models are established, one is for an uncovered helicopter fuel tank without protection frame, and the other is for fuel tank with protection frame. The dynamic responses of the two types of fuel tanks impinging on the ground with velocities of 17.3 m/s are numerically simulated for the purpose of analyzing energy-absorbing capabilities of the textile layer and protection frame. The feasibility of the current crashworthiness design of the fuel tank is examined though comparing the dynamic response behaviors of the two fuel tanks.

关键词： fuel tank crashworthiness helicopter FEM

The Forecast Skills and Predictability Sources of Marine Heatwaves in the NUIST-CFS1.0 Hindcasts

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Advances in Atmospheric Sciences 2024年第8期41卷 1589-1600页

作者： Jing MA Haiming XU Changming DONG Jing-jia luo Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters/KLME/ILCEC/Institute of Climate and Application Research(ICAR) Nanjing University of Information Science and TechnologyNanjingJiangsu 210044China

Using monthly observations and ensemble hindcasts of the Nanjing University of Information Science and Technology Climate Forecast System(NUIST-CFS1.0) for the period 1983–2020, this study investigates the forecast skill of marine heatwaves(MHWs) over the globe and the predictability sources of the MHWs over the tropical oceans. The MHW forecasts are demonstrated to be skillful on seasonal-annual time scales, particularly in tropical oceans. The forecast skill of the MHWs over the tropical Pacific Ocean(TPO) remains high at lead times of 1–24 months, indicating a forecast better than random chance for up to two years. The forecast skill is subject to the spring predictability barrier of El Nino-Southern Oscillation(ENSO). The forecast skills for the MHWs over the tropical Indian Ocean(TIO), tropical Atlantic Ocean(TAO), and tropical Northwest Pacific(NWP) are lower than that in the TPO. A reliable forecast at lead times of up to two years is shown over the TIO, while a shorter reliable forecast window(less than 17 months) occurs for the TAO and ***, the forecast skills for the TIO, TAO, and NWP are seasonally dependent. Higher skills for the TIO and TAO appear in boreal spring, while a greater skill for the NWP emerges in late summer-early autumn. Further analyses suggest that ENSO serves as a critical source of predictability for MHWs over the TIO and TAO in spring and MHWs over the NWP in summer.

关键词： marine heatwaves NUIST-CFS1.0 hindcasts forecast skill predictability source ENSO

Distinct Evolution of the SST Anomalies in the Far Eastern Pacific between the 1997/98 and 2015/16 Extreme El Niños

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Advances in Atmospheric Sciences 2022年第6期39卷 927-942页

作者： Shaolei TANG Jing-jia luo Lin CHEN Yongqiang YU Institute for Climate and Application Research(ICAR) Nanjing University of Information Science and TechnologyNanjing 210044China Key Laboratory of Meteorological Disaster Ministry of Education(KLME)/ILCEC/CIC-FEMDNanjing University of Information Science and TechnologyNanjing 210044China State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics(LASG) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China Center for Ocean Mega-Science Chinese Academy of SciencesQingdao 266071China

The 2015/16 El Niño displayed a distinct feature in the SST anomalies over the far eastern Pacific(FEP)compared to the 1997/98 extreme *** contrast to the strong warm SST anomalies in the FEP in the 1997/98 event,the FEP warm SST anomalies in the 2015/16 El Niño were modest and accompanied by strong southeasterly wind anomalies in the southeastern *** possible underlying causes of this distinct difference in the FEP may improve understanding of the diversity of extreme El Niñ***,we employ observational analyses and numerical model experiments to tackle this ***-layer heat budget analysis suggests that compared to the 1997/98 event,the modest FEP SST warming in the 2015/16 event was closely related to strong vertical upwelling,strong westward current,and enhanced surface evaporation,which were caused by the strong southeasterly wind anomalies in the southeastern *** strong southeasterly wind anomalies were initially triggered by the combined effects of warm SST anomalies in the equatorial central and eastern Pacific(CEP)and cold SST anomalies in the southeastern subtropical Pacific in the antecedent winter,and then sustained by the warm SST anomalies over the northeastern subtropical Pacific and *** contrast,southeasterly wind anomalies in the 1997/98 El Niño were partly restrained by strong anomalously negative sea level pressure and northwesterlies in the northeast flank of the related anomalous cyclone in the subtropical South *** addition,the strong southeasterly wind and modest SST anomalies in the 2015/16 El Niño may also have been partly related to decadal climate variability.

关键词： El Nño-Southern Oscillation extreme El Niño El Niño diversity far eastern Pacific decadal climate variability

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Journal of Integrative Plant Biology 2012年第10期54卷 814-827页

作者： Guo luo Hongya Gu Jingjing Liu Li-jia Qu State Key Laboratory for Protein and Plant Gene Research College of Life SciencesPeking-Tsinghua Center of Life SciencesPeking UniversityBeijing 100871China The National Plant Gene Research Center Beijing 100101China

Ubiquitination of proteins is one of the critical regulatory mechanisms in eukaryotes. In higher plants, protein ubiquitination plays an essential role in many biological processes, including hormone signaling, photomorphogenesis, and pathogen defense. However, the roles of protein ubiquitination in the repro- ductive process are not clear. In this study, we identified four plant-specific RING-finger genes designated Aberrant_Pollen Development 1_ （APD1） to APD4, as regulators of pollen mitosis II （PMII） in Arabidopsis thaliana （L.）. The apdl apd2 double mutant showed a significantly increased percentage of bicellular-like pollen at the mature pollen stage. Further downregulation of the APD3 and APD4 transcripts in apdl apd2 by RNA interference （RNAi） resulted in more severe abnormal bicellular-like pollen phenotypes than in apdl apd2, suggesting that cell division was defective in male gametogenesis. All of the four genes were expressed in multiple stages at different levels during male gametophyte development. Confocal analysis using green florescence fusion proteins （GFP） GFP-APD1 and GFP-APD2 showed that APDs are associated with intracellular membranes. Furthermore, APD2 had E2-dependent E3 ligase activity in vitro, and five APD2-interacting proteins were identified. Our results suggest that these four genes may be involved, redundantly, in regulating the PMII process during male gametogenesis.

关键词： Male gametogenesis pollen mitosis II RING-finger E3 ligase Arabidopsis.

Glutamate oxidase-integrated biomimetic Fe_(3)O_(4) hybrids as cascade nanozymes for glutamate detection

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Particuology 2024年第5期88卷 192-200页

作者： Peikun Li Yanchao Wang Xiuyan luo Zixin Geng jiahui jia Ruirui Wang jiandong Cui Hongjie Bian Shiru jia State Key Laboratory of Food Nutrition and Safety Laboratory of Industrial Fermentation MicrobiologyMinistry of EducationTianjin University of Science and TechnologyTianjin300457China Sports Department Hebei University of Science and TechnologyShijiazhang050000China Research Center for Fermentation Engineering of Hebei College of Bioscience and BioengineeringHebei University of Science and TechnologyShijiazhang050000China

Herein,a new nanozyme/natural enzyme hybrid biosensor was established for ultrasensitive l-glutamic acid(L-Glu)*** Fe_(3)O_(4) nanoparticles with peroxidase-like activity and stability was used as a nanozyme and carrier for immobilizing l-Glutamate oxidase(GLOD)through Schiffff base reaction to construct a chem-enzyme cascade *** resultant Fe_(3)O_(4)-GOLD exhibited a wide linear range(10−500μM)and a low detection limit of 6.03μM for L-Glu ***,the Fe_(3)O_(4)-GOLD exhibited excellent pH stability,thermal stability,reusability and storage *** repeated nine cycles,Fe_(3)O_(4)-GOLD still retained 70%of its initial ***,Fe_(3)O_(4)-GOLD maintained 50%of its initial activity after storage for 20 days,while free GLOD only retained 20%of its initial *** strategy of integrating biomimetic Fe 3 O4 and natural enzymes for cascade catalysis makes it possible to design an efficient and stable chemo-enzyme composite catalysts,which are promising for applications in biosensing and biomimetic catalysis.

关键词： Fe_(3)O_(4) nanozyme GLOD Chemo-enzymes Glutamate detection

A review on SnFe2O4 and their composites: Synthesis, properties, and emerging applications

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Progress in Natural Science:Materials International 2022年第5期32卷 517-527页

作者： Hongru Han Yi luo Yuefa jia N.Hasan Chunli Liu School of Water and Environment Chang'an University Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region (Chang'an University) Department of Physics and Oxide Research Center Hankuk University of Foreign Studies

Tin ferrite(SnFe2O4) and their composites have been extensively studied due to their unique functional properties including appealing electronic band structure, good chemical stability, high magnetization, excellent biocompatible and earth-abundant nature. Over the past few years, SnFe2O4and their composites have been well designed and investigated for various kind of applications. In this review, the most important methods for SnFe2O4and their composites synthesis, such as co-precipitation, hydrothermal, solvothermal and sol-gel techniques are summarized. It is important to emphasize that this review mainly focuses on the application of SnFe2O4and their composites for environmental remediation, lithium-ion batteries and hydrogen peroxide sensors, which are discussed in detail for the first time. Apart from that, the key factors and essential means to improve their performance and functionality are systematically reported. Finally, the development prospect and challenge of SnFe2O4and their composites are introduced. It is anticipated that this review will be helpful in development of SnFe2O4and their composites with ameliorated performances for practical application in various fields.

关键词： SnFe 2 O 4 Synthesis Environmental remediation Lithium-ion batteries Hydrogen peroxide sensors

A robust vector tracking loop structure based on potential bias analysis

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Chinese Journal of Aeronautics 2024年第4期37卷 405-420页

作者： Qiongqiong jia Yiran luo Bing XU Li-Ta HSU Renbiao WU Tianjin Key Lab for Advanced Signal Processing Civil Aviation University of ChinaTianjin 300300China Interdisciplinary Division of Aeronautical and Aviation Engineering The Hong Kong Polytechnic University999077Hong KongChina Department of Geomatics Engineering University of CalgaryCalgary T2N1N4Canada

This paper proposes a robust vector tracking loop structure based on potential bias analysis. The influence of four kinds of biases on the existing two implementations of Vector Tracking Loops(VTLs) is illustrated by theoretical analysis and numerical simulations, and the following findings are obtained. Firstly, the initial user state bias leads to steady navigation solution bias in the relative VTL, while new measurements can eliminate it in the absolute VTL. Secondly, the initial code phase bias is transferred to the following navigation solutions in the relative VTL, while new measurements can eliminate it in the absolute VTL. Thirdly, the user state bias induced by erroneous navigation solution of VTLs can be eliminated by both of the two VTLs. Fourthly,the multipath/NLOS likely affects the two VTLs, and the induced tracking bias in the duration of the multipath/NLOS would decrease the performance of VTLs. Based on the above analysis,a robust VTL structure is proposed, where the absolute VTL is selected for its robustness to the two kinds of initialization biases;meanwhile, the instant bias detection and correction method is used to improve the performance of VTLs in the duration of the multipath/NLOS. Numerical simulations and experimental results verify the effectiveness of the proposed robust VTL structure.

关键词： Global Navigation Satellite System(GNSS) Vector Tracking Loop(VTL) Multipath Non-Line-of-Sight(NLOS) Tracking bias propagation Least Absolute Shrinkage and Selection Operator(LASSO)

Simulation of the Impacts of Single LEO Satellite Orbit Parameters on the Distribution and Number of Occultation Events

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Geo-Spatial Information Science 2006年第1期9卷 13-17页

作者： XU Xiaohua LI Zhenghang luo jia Institute of Satellite Application School of Geodesy and Geomatics Wuhan University 129 Luoyu Road Wuhan 430079 China

Focusing on carrying out GPS occultation observat io ns with a receiver set on LEO satellite, this paper develops the LEO orbit simul ation system based on which the occultation events can be simulated taking into account the geometric relationship of the satellites and the field of view of th e receiver antenna. In this paper, the impacts of 4 types of LEO orbit parameter s including argument of latitude (AOL), right ascension of ascending node (RAAN) , orbit height and orbit inclination on the distribution and number of occultati on events observed with a single LEO satellite are discussed through simulat ion and some conclusions are drawn.

关键词： LEO satellite GPS occultation orbit parameters