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Pumping-induced Well Hydraulics and Groundwater Budget in a Leaky Aquifer System with Vertical Heterogeneity in Aquitard Hydraulic Properties
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作者 ZHUANG Chao LÜChenyang +5 位作者 YAN Long LI Yabing ZHOU Zhifang WANG Jinguo DOU Zhi Walter A.ILLMAN 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2024年第2期477-490,共14页
In groundwater hydrology,aquitard heterogeneity is often less considered compared to aquifers,despite its significant impact on groundwater hydraulics and groundwater resources evaluation.A semi-analytical solution is... In groundwater hydrology,aquitard heterogeneity is often less considered compared to aquifers,despite its significant impact on groundwater hydraulics and groundwater resources evaluation.A semi-analytical solution is derived for pumping-induced well hydraulics and groundwater budget with consideration of vertical heterogeneity in aquitard hydraulic conductivity(K)and specific storage(S_(s)).The proposed new solution is innovative in its partitioning of the aquitard into multiple homogeneous sub-layers to enable consideration of various forms of vertically heterogeneous K or S_(s).Two scenarios of analytical investigations are explored:one is the presence of aquitard interlayers with distinct K or S_(s) values,a common field-scale occurrence;another is an exponentially depth-decaying aquitard S_(s),a regional-scale phenomenon supported by statistical analysis.Analytical investigations reveal that a low-K interlayer can significantly increase aquifer drawdown and enhance aquifer/aquitard depletion;a high-S_(s) interlayer can noticeably reduce aquifer drawdown and increase aquitard depletion.Locations of low-K or high-S_(s) interlayers also significantly impact well hydraulics and groundwater budget.In the context of an exponentially depth-decaying aquitard S_(s),a larger decay exponent can enhance aquifer drawdown.When using current models with a vertically homogeneous aquitard,half the sum of the geometric and harmonic means of exponentially depth-decaying aquitard S_(s) should be used to calculate aquitard depletion and unconfined aquifer leakage. 展开更多
关键词 HYDROGEOLOGY AQUITARD vertical heterogeneity semi-analytical solution well hydraulics groundwater budget
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Adaptive Robust Servo Control for Vertical Electric Stabilization System of Tank and Experimental Validation 被引量:1
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作者 Darui Lin Xiuye Wang +1 位作者 Yimin Wang Guolai Yang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第1期326-342,共17页
A tracking stability control problem for the vertical electric stabilization system of moving tank based on adaptive robust servo control is addressed.This paper mainly focuses on two types of possibly fast timevaryin... A tracking stability control problem for the vertical electric stabilization system of moving tank based on adaptive robust servo control is addressed.This paper mainly focuses on two types of possibly fast timevarying but bounded uncertainty within the vertical electric stabilization system:model parameter uncertainty and uncertain nonlinearity.First,the vertical electric stabilization system is constructed as an uncertain nonlinear dynamic system that can reflect the practical mechanics transfer process of the system.Second,the dynamical equation in the form of state space is established by designing the angular tracking error.Third,the comprehensive parameter of system uncertainty is designed to estimate the most conservative effects of uncertainty.Finally,an adaptive robust servo control which can effectively handle the combined effects of complex nonlinearity and uncertainty is proposed.The feasibility of the proposed control strategy under the practical physical condition is validated through the tests on the experimental platform.This paper pioneers the introduction of the internal nonlinearity and uncertainty of the vertical electric stabilization system into the settlement of the tracking stability control problem,and validates the advanced servo control strategy through experiment for the first time. 展开更多
关键词 Adaptive robust servo control Experimental validation Nonlinearity compensation system uncertainty vertical electric stabilization system
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SensFL:Privacy-Preserving Vertical Federated Learning with Sensitive Regularization
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作者 Chongzhen Zhang Zhichen Liu +4 位作者 Xiangrui Xu Fuqiang Hu Jiao Dai Baigen Cai Wei Wang 《Computer Modeling in Engineering & Sciences》 SCIE EI 2025年第1期385-404,共20页
In the realm of Intelligent Railway Transportation Systems,effective multi-party collaboration is crucial due to concerns over privacy and data silos.Vertical Federated Learning(VFL)has emerged as a promising approach... In the realm of Intelligent Railway Transportation Systems,effective multi-party collaboration is crucial due to concerns over privacy and data silos.Vertical Federated Learning(VFL)has emerged as a promising approach to facilitate such collaboration,allowing diverse entities to collectively enhance machine learning models without the need to share sensitive training data.However,existing works have highlighted VFL’s susceptibility to privacy inference attacks,where an honest but curious server could potentially reconstruct a client’s raw data from embeddings uploaded by the client.This vulnerability poses a significant threat to VFL-based intelligent railway transportation systems.In this paper,we introduce SensFL,a novel privacy-enhancing method to against privacy inference attacks in VFL.Specifically,SensFL integrates regularization of the sensitivity of embeddings to the original data into the model training process,effectively limiting the information contained in shared embeddings.By reducing the sensitivity of embeddings to the original data,SensFL can effectively resist reverse privacy attacks and prevent the reconstruction of the original data from the embeddings.Extensive experiments were conducted on four distinct datasets and three different models to demonstrate the efficacy of SensFL.Experiment results show that SensFL can effectively mitigate privacy inference attacks while maintaining the accuracy of the primary learning task.These results underscore SensFL’s potential to advance privacy protection technologies within VFL-based intelligent railway systems,addressing critical security concerns in collaborative learning environments. 展开更多
关键词 vertical federated learning PRIVACY DEFENSES
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Vertical Distribution of Soil Carbon, Nitrogen, and Phosphorus in Typical Chinese Terrestrial Ecosystems 被引量:9
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作者 CHAI Hua YU Guirui +3 位作者 HE Nianpeng WEN Ding LI Jie FANG Jiangping 《Chinese Geographical Science》 SCIE CSCD 2015年第5期549-560,共12页
Characterization of the vertical distribution of soil organic carbon(C), nitrogen(N), and phosphorus(P) may improve our ability to accurately estimate soil C, N, and P storage. Based on a database of 21 354 records in... Characterization of the vertical distribution of soil organic carbon(C), nitrogen(N), and phosphorus(P) may improve our ability to accurately estimate soil C, N, and P storage. Based on a database of 21 354 records in 74 long-term monitoring plots from 2004 to 2013 in the Chinese Ecosystem Research Network(CERN), we built fitting functions to quantify the vertical distribution of soil C, N, and P(up to 100 cm depth) in the typical Chinese terrestrial ecosystems. The decrease of soil C, N, and P content with depth can be well fitted with various mathematical functions. The fitting functions differed greatly between artificial(agriculture) and natural(desert, forest, and grassland) ecosystems, and also differed with respect to soil C, N, and P content. In both the artificial and natural ecosystems, the best fitting functions were exponential functions for C, quadratic functions for N, and quadratic functions for P. Furthermore, the stoichiometric ratios of soil C, N, and P were ranked in descending order: grassland > forest > agriculture > desert, and were also associated with climate. This study is the first to build the fitting functions for the profile distribution of soil C, N, and P in China at a national scale. Our findings provide a scientific basis to accurately assess the storage of C, N, and P in soils at a large scale, especially for the integrative analysis of historical data. 展开更多
关键词 soil profile STORAGE STOICHIOMETRY vertical distribution China
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Active Low-frequency Vertical Vibration Isolation System for Precision Measurements 被引量:6
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作者 WU Kang LI Gang +1 位作者 HU Hua WANG Lijun 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2017年第1期164-169,共6页
Low-fi'equency vertical vibration isolation systems play important roles in precision measurements to reduce seismic and environmental vibration noise. Several types of active vibration isolation systems have been de... Low-fi'equency vertical vibration isolation systems play important roles in precision measurements to reduce seismic and environmental vibration noise. Several types of active vibration isolation systems have been developed. However, few researches focus on how to optimize the test mass install position in order to improve the vibration transmissibility. An active low-frequency vertical vibration isolation system based on an earlier instrument, the Super Spring, is designed and implemented. The system, which is simple and compact, consists of two stages: a parallelogram-shaped linkage to ensure vertical motion, and a simple spring-mass system. The theoretical analysis of the vibration isolation system is presented, including terms erroneously ignored before. By carefully choosing the mechanical parameters according to the above analysis and using feedback control, the resonance frequency of the system is reduced from 2.3 to 0.03 Hz, a reduction by a factor of more than 75. The vibration isolation system is installed as an inertial reference in an absolute gravimeter, where it improved the scatter of the absolute gravity values by a factor of 5. The experimental results verifies the improved performance of the isolation system, making it particularly suitable for precision experiments. The improved vertical vibration isolation system can be used as a prototype for designing high-performance active vertical isolation systems. An improved theoretical model of this active vibration isolation system with beam-pivot configuration is proposed, providing fundamental guidelines for vibration isolator design and assembling. 展开更多
关键词 vibration isolation vertical low frequency ACTIVE
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Exploitation technology of pressure relief coalbed methane in vertical surface wells in the Huainan coal mining area 被引量:13
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作者 HAN Jia-zhang SANG Shu-xun +1 位作者 CHENG Zhi-zhong HUANG Hua-zhou 《Mining Science and Technology》 EI CAS 2009年第1期25-30,共6页
Exploitation technology of pressure relief coalbed methane in vertical surface wells is a new method for exploration of gas and coalbed methane exploitation in mining areas with high concentrations of gas, where tecto... Exploitation technology of pressure relief coalbed methane in vertical surface wells is a new method for exploration of gas and coalbed methane exploitation in mining areas with high concentrations of gas, where tectonic coal developed. Studies on vertical surface well technology in the Huainan Coal Mining area play a role in demonstration in the use of clean, new energy resources, preventing and reducing coal mine gas accidents and protecting the environment. Based on the practice of gas drainage engineering of pressure relief coalbed methane in vertical surface wells and combined with relative geological and exploration en- gineering theories, the design principles of design and structure of wells of pressure relief coalbed methane in vertical surface wells are studied. The effects of extraction and their causes are discussed and the impact of geological conditions on gas production of the vertical surface wells are analyzed. The results indicate that in mining areas with high concentrations of gas, where tectonic coal developed, a success rate of pressure relief coalbed methane in surface vertical well is high and single well production usually great. But deformation due to coal exploitation could damage boreholes and cause breaks in the connection between aquifers and bore-holes, which could induce a decrease, even a complete halt in gas production of a single well. The design of well site location and wellbore configuration are the key for technology. The development of the geological conditions for coalbed methane have a significant effect on gas production of coalbed methane wells. 展开更多
关键词 pressure relief coalbed methane EXPLOITATION vertical surface well Huainan coal mining area
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A mechanistic model of heat transfer for gas–liquid flow in vertical wellbore annuli 被引量:4
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作者 Bang-Tang Yin Xiang-Fang Li Gang Liu 《Petroleum Science》 SCIE CAS CSCD 2018年第1期135-145,共11页
The most prominent aspect of multiphase flow is the variation in the physical distribution of the phases in the flow conduit known as the flow pattern. Several different flow patterns can exist under different flow co... The most prominent aspect of multiphase flow is the variation in the physical distribution of the phases in the flow conduit known as the flow pattern. Several different flow patterns can exist under different flow conditions which have significant effects on liquid holdup, pressure gradient and heat transfer. Gas-liquid two-phase flow in an annulus can be found in a variety of practical situations. In high rate oil and gas production, it may be beneficial to flow fluids vertically through the annulus configuration between well tubing and casing. The flow patterns in annuli are different from pipe flow. There are both casing and tubing liquid films in slug flow and annular flow in the annulus. Multiphase heat transfer depends on the hydrodynamic behavior of the flow. There are very limited research results that can be found in the open literature for multiphase heat transfer in wellbore annuli. A mechanistic model of multiphase heat transfer is developed for different flow patterns of upward gas-liquid flow in vertical annuli. The required local flow parameters are predicted by use of the hydraulic model of steady-state multiphase flow in wellbore annuli recently developed by Yin et al. The modified heat-transfer model for single gas or liquid flow is verified by comparison with Manabe's experimental results. For different flow patterns, it is compared with modified unified Zhang et al. model based on representative diameters. 展开更多
关键词 Gas-liquid flow vertical annuli HEATTRANSFER Tubing liquid film Casing liquid film
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Dynamics of vertical pipe in deep-ocean mining system 被引量:3
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作者 禹宏云 刘少军 《Journal of Central South University of Technology》 EI 2007年第4期552-556,共5页
A 3-D geometrical nonlinear model for the entire lift system of 1000-m sea trial system of China Ocean Mineral Resources R&D Association was established with finite element method.The model was utilized to analyze... A 3-D geometrical nonlinear model for the entire lift system of 1000-m sea trial system of China Ocean Mineral Resources R&D Association was established with finite element method.The model was utilized to analyze the dynamic characteristics of the vertical pipe under the influence of moving velocity,current direction and wave.The simulation results show that the axial stress is dominant on the vertical pipe,its maximum is located at the pipe top,all stresses are much less than the allowable value of the vertical pipe and joint;the heave motion leads to violent fluctuation of the force and stress,but a period of 8 s is not likely to resonate the present pipe;against the current,0.50 m/s is the suggested moving velocity of the ship and miner,while along the current,the moving velocity can be slightly higher than 0.75 m/s. 展开更多
关键词 deep-ocean mining DYNAMICS vertical pipe finite element method geometrical nonlinearity
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Vertical Distribution of Soil Nematode Communities under Different Tillage Systems in Lower Reaches of Liaohe River 被引量:2
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作者 HOU Xuekun HU Ning +2 位作者 ZHANG Xiaoke LIANG Lei ZHAI Ruichang 《Chinese Geographical Science》 SCIE CSCD 2010年第2期106-111,共6页
Vertical distribution of soil nematode communities under conventional tillage (CT),no-tillage (NT) and fallow field (FF) treatments in the Lower Reaches of the Liaohe River was investigated at six soil depths (0-5 cm,... Vertical distribution of soil nematode communities under conventional tillage (CT),no-tillage (NT) and fallow field (FF) treatments in the Lower Reaches of the Liaohe River was investigated at six soil depths (0-5 cm,5-15 cm,15-30 cm,30-50 cm,50-75 cm and 75-100 cm). The results show that total nematode abundance gradually decreases with depth,and the highest number of total nematodes is observed at 0-5 cm depth under NT and FF treatments. The number of fungivores and plant parasites is significantly higher under FF and NT treatments than under CT treatment at the 0-5 cm depth. There is significant soil depth effect on the abundances of bacterivores and omnivores-predators,which exhibits a similar trend to that of total nematodes; whereas,no significant tillage effect is found. Tillage effect on soil nematode communities can be reflected by values of relative tillage response of index V. Results of index V indicate that total nematodes,bacterivores,fungivores and plant parasites are mildly inhibited,and omnivores-predators is moderately inhibited under CT treatment; while,under FF treatment total nematodes is mildly,and fungivores and plant parasites are moderately stimulated,respectively. 展开更多
关键词 soil nematode tillage system vertical distribution tillage response
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Vertical Transport in GaAs/AlAs Superlattice with Weak Coupling Between Wells 被引量:2
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作者 HE Li-xiong SUN Bao-quan WU Jian-qing 《Chinese Physics Letters》 SCIE CAS CSCD 1998年第4期293-295,共3页
Vertical transport I-V relations of type-I GaAs/A1As superlattices with doped wells and weak coupling between wells at 77K were investigated with quasistatic and dynamic method.Spontaneous current oscillations are als... Vertical transport I-V relations of type-I GaAs/A1As superlattices with doped wells and weak coupling between wells at 77K were investigated with quasistatic and dynamic method.Spontaneous current oscillations are also investigated.The domain formation time 70±30 ns is directly measured.By using discrete-tunneling model,the key parameters of the relation between tunneling current and the bias between adjacent wells were quantitatively determined from the experimental data. 展开更多
关键词 vertical TUNNELING COUPLING
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Vegetative Growth Characters of the Young Apple Trees Trained in Vertical Axis System 被引量:2
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作者 LI Shao-hua, LI Ming, LIU Guo-jie and MENG Zhao-qing( Department of Fruit Science, China Agricultural University, Beijing 100094 , P. R. China Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou 450009, P.R. China ) 《Agricultural Sciences in China》 CAS CSCD 2002年第7期752-756,共5页
Vegetative growth of young apple trees trained in vertical axis were studied with ' Red Fuji', 'Jonagold', 'Orin' and ' Starkrimson' on M7, MM106, M26 interstocks in northern China. Abo... Vegetative growth of young apple trees trained in vertical axis were studied with ' Red Fuji', 'Jonagold', 'Orin' and ' Starkrimson' on M7, MM106, M26 interstocks in northern China. About 30 branches sprouted from the central leader of the trees during the 4 years after planting for ' Red Fuji' and 'Jonagold', and 26.7 and 20 branches respectively for 'Orin' and 'Starkrimson'. Moreover the 2-year-old section of the central leader had the strongest capacity to sprout new branches (and sometimes the 1-year-old section too), and sprouted more new shoots than the other section. The total new shoots including spurs on the 4-year-old trees reached 631 per tree for 'Jonagold', about 480 for 'Red Fuji' and 'Orin', and 312 for 'Starkrimson'. Percentage of spurs was about 61% for 'Red Fuji', 73% for 'Jonagold' and 'Orin', and 81% for 'Starkrimson'. Growth vigor of the central leader and limbs of the young apple trees could quickly decline: the growth of the central leader decreased markedly in the fourth year after planting, and branches from the central leader grew vigorously only in the current growth season or in the first two years after branching. 展开更多
关键词 APPLE vertical axis Vegetative growth INTERSTOCK
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PERFORMANCE OF ULTRA-LOW FREQUENCY PASSIVE VERTICAL VIBRATION ISOLATION SYSTEM WITH REVERSE PENDULUM 被引量:2
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作者 Zhao Pengfei Huang Yuying +1 位作者 Tang Mengxi Sun Shijun 《Acta Mechanica Solida Sinica》 SCIE EI 2002年第1期45-48,共4页
A novel long period passive vertical vibration isolatorconstructed by mounting reverse pendu- lums on two pairs of torsionsprings is presented. By theoretical analysis and numericalcalculation, it is shown that the is... A novel long period passive vertical vibration isolatorconstructed by mounting reverse pendu- lums on two pairs of torsionsprings is presented. By theoretical analysis and numericalcalculation, it is shown that the isolator can achieve much longerresonant period due to gravitational positive feedback and is smallerin size than the current torsion spring isolators with the samegeometric parameters. 展开更多
关键词 vertical vibration isolation torsion spring reverse pendulum resonantperiod
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Vertical section phase diagrams of La−Fe−B ternary system 被引量:2
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作者 Qi WEI Zhao LU +4 位作者 Qing-rong YAO Jian-qiu DENG Jiang WANG Huai-ying ZHOU Guang-hui RAO 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2021年第6期1748-1757,共10页
The vertical sections of the La−Fe−B system were investigated using electron probe microanalysis and differential thermal analysis.Based on the microstructures and phase compositions of the as-cast and equilibrium all... The vertical sections of the La−Fe−B system were investigated using electron probe microanalysis and differential thermal analysis.Based on the microstructures and phase compositions of the as-cast and equilibrium alloys,together with their heat flow−temperature curves,phase diagrams for three vertical sections were drawn:La_(x)Fe_(82)B_(y)(x+y=18),La_(x)Fe_(70)B_(y)(x+y=30)and La_(x)Fe_(53)B_(y)(x+y=47),where x and y represent mass fraction of La and B,respectively,%.Additionally,according to the phase diagrams,the compound La2Fe14B was identified as a stable phase at high temperatures.It was found to be stable between 926.2 and 792.6℃;at low temperatures,however,it decomposed into α-La,α-Fe and LaFe_(4)B_(4),according to the reaction La_(2)Fe_(14)B→α-Fe+α-La+LaFe_(4)B_(4). 展开更多
关键词 solidification characteristics vertical section phase diagram equilibrium alloy high temperature stable compound
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Vertical handoff algorithm in heterogeneous networks to maximize system benefit 被引量:1
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作者 Xie Shengdong Wu Meng 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2009年第5期1124-1131,共8页
A new vertical handoff decision algorithm is proposed to maximize the system benefit in heterogeneous wireless networks which comprise cellular networks and wireless local area networks (WLANs). Firstly the block pr... A new vertical handoff decision algorithm is proposed to maximize the system benefit in heterogeneous wireless networks which comprise cellular networks and wireless local area networks (WLANs). Firstly the block probability, the drop probability and the number of users in the heterogeneous networks are calculated in the channel-guard call admission method, and a function of the system benefit which is based on the new call arrival rate and the handoff call arrival rate is proposed. Then the optimal radius of WLAN is obtained by using simulation annealing (SA) method to maximize the benefit. All the nodes should handoff from cellular network to WLAN if they enter WLAN's scope and handoff from WLAN to cellular network if they leave the scope. Finally, the algorithm in different new call arrival rates and handoff call arrival rates is analyzed and results show that it can achieve good effects. 展开更多
关键词 heterogeneous wireless networks vertical handoff system benefit simulated annealing optimization.
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Acceleration-Dependent Analysis of Vertical Ball Screw Feed System without Counterweight 被引量:1
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作者 Cunfan Zou Huijie Zhang +3 位作者 Jun Zhang Dongdong Song Hui Liu Wanhua Zhao 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2021年第3期243-255,共13页
The distinguishing feature of a vertical ball screw feed system without counterweight is that the spindle system weight directly acts on the kinematic joints.Research into the dynamic characteristics under acceleratio... The distinguishing feature of a vertical ball screw feed system without counterweight is that the spindle system weight directly acts on the kinematic joints.Research into the dynamic characteristics under acceleration and deceleration is an important step in improving the structural performance of vertical milling machines.The magnitude and direction of the inertial force change significantly when the spindle system accelerates and decelerates.Therefore,the kinematic joint contact stiffness changes under the action of the inertial force and the spindle system weight.Thus,the system transmission stiffness also varies and affects the dynamics.In this study,a variable-coefficient lumped parameter dynamic model that considers the changes in the spindle system weight and the magnitude and direction of the inertial force is established for a ball screw feed system without counterweight.In addition,a calculation method for the system stiffness is provided.Experiments on a vertical ball screw feed system under acceleration and deceleration with different accelerations are also performed to verify the proposed dynamic model.Finally,the influence of the spindle system position,the rated dynamic load of the screw-nut joint,and the screw tension force on the natural frequency of the vertical ball screw feed system under acceleration and deceleration are studied.The results show that the vertical ball screw feed system has obviously different variable dynamics under acceleration and deceleration.The influence of the rated dynamic load and the spindle system position on the natural frequency under acceleration and deceleration is much greater than that of the screw tension force. 展开更多
关键词 vertical ball screw feed system Acceleration and deceleration Joints stiffness Variable-coefficient lumped parameter model Power spectral density Natural frequency
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Hg Vertical Transference in Soil Water System *1 被引量:1
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作者 GUOYIJUN MOUSUSEN 《Pedosphere》 SCIE CAS CSCD 1998年第2期187-191,共5页
Hg vertical transference in soil water system was studied by analyzing Hg vertical distribution in soil column after adding Hg and one of the two leacheates, deionized water or acid rain, into soil column. The result... Hg vertical transference in soil water system was studied by analyzing Hg vertical distribution in soil column after adding Hg and one of the two leacheates, deionized water or acid rain, into soil column. The results indicated that Hg was hardly transferable in purple soil. About 86%~88% of the total soil Hg was distributed in the top layer (0~2 cm) and no Hg was detected in the leakage when the purple soil column was leached by deionized water and simulated acid rain. But Hg was more movable in yellow soil with only about 20%~22% of the total soil Hg distributed in the top layer (0~2 cm), and about 17%~25% washed out from the soil column by deionized water and simulated acid rain. Increment in soil bulk density could reduce Hg leaching, thus the more the Hg kept in soil, the less the Hg leached into underground water. Deionized water and acid rain almost played the same role in leaching Hg. Bentonite was most efficient in preventing Hg from vertical transferring in the soil column. 展开更多
关键词 HG SOIL vertical transference
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Chemical characteristics and estimation on the vertical flux of N,P,Si in upwelling area of Taiwan Strait 被引量:1
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作者 Chen Shuitu and Ruan Wuqi(Fujian Institute of Oceanology, Xiamen 361012, China) 《Acta Oceanologica Sinica》 SCIE CAS CSCD 1995年第3期383-392,共10页
Based on the data obtained from oceanographic surveys at the central and northern parts of the TaiwanStrait during the period from 1983 to 1988, it is showed that the nutrient content in the coastal and bottom waters ... Based on the data obtained from oceanographic surveys at the central and northern parts of the TaiwanStrait during the period from 1983 to 1988, it is showed that the nutrient content in the coastal and bottom waters isrelatively high with an upward and offward decrease, and that the upwelling in the Fujian coastal area controls the distribution of nutrients in summer.The upwelling water is characterized by 2. 29 μmol/dm ̄3 of nitrate; 2. 83 μmol/dm ̄3of silicate; 0. 20 μmol/dm ̄3 of dissolved inorganic phosphate,respectively. Significant correlation between nutrientsand dissolved oxygen content and its degree of saturation, temperature, and salinity, respectively are found in the upweiling area. Average of N/P ratio in the area(15. 9) approaches to Redfield ratio. Their vertical flux is estimated tobe 23. 6 mg/(m ̄2·d) for - P, 223 mg/(m ̄2·d) for NO-N, 302 mg/(m ̄2·d) for SiO-Si, respectively,which is the main source Of nutients in the areas in summer. The mean of the flux of P and NO-N is about86 % and 73% necessary for phytoplankton in the euphotic zone. 展开更多
关键词 UPwellING the Taiwan Strait nutrients distribution vertical flux
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Failure characteristics of surface vertical wells for relieved coal gas and their influencing factors in Huainan mining area 被引量:3
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作者 Xu Honkie Sang Shuxun +2 位作者 Fang Liangcai 6 Huang Huazhou Ren Bo 《Mining Science and Technology》 EI CAS 2011年第1期83-88,共6页
Based on data from through-hole and logging,we studied the failure characteristics of surface drainage wells for relieved coal gas in Huainan mining area and its influencing factors.The results show that the damaged p... Based on data from through-hole and logging,we studied the failure characteristics of surface drainage wells for relieved coal gas in Huainan mining area and its influencing factors.The results show that the damaged positions of drainage wells are mainly located at the thick clay layer in the low alluvium and the lithological interface in the upper section of bedrock in west mining area.The failure depth of casing is 244-670 m and concentrates at about 270-460 m deep.These damaged positions are mainly located in the bending zone according to three zones of rock layers in the vertical section above the roof divided. Generally,the casing begins to deform or damage before the face line about 30-150 m.Special formation structure and rock mass properties are the direct causes of the casing failure,high mining height and fast advancing speed are fundamental reasons for rock mass damage.However,the borehole configuration and spacing to the casing failure are not very clear. 展开更多
关键词 Huainan mining area vertical wells for relieved coal gas Failure characteristics Influencing factors
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Granular behaviour under bi-directional shear with constant vertical stress and constant volume 被引量:1
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作者 Min Zhang Yunming Yang +1 位作者 Hanwen Zhang Qi Li 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第10期4300-4318,共19页
This paper aims to investigate the role of bi-directional shear in the mechanical behaviour of granular materials and macro-micro relations by conducting experiments and discrete element method(DEM)modelling.The bi-di... This paper aims to investigate the role of bi-directional shear in the mechanical behaviour of granular materials and macro-micro relations by conducting experiments and discrete element method(DEM)modelling.The bi-directional shear consists of a static shear consolidation and subsequent shear under constant vertical stress and constant volume conditions.A side wall node loading method is used to exert bi-directional shear of various angles.The results show that bi-directional shear can significantly influence the mechanical behaviour of granular materials.However,the relationship between bidirectional shear and mechanical responses relies on loading conditions,i.e.constant vertical stress or constant volume conditions.The stress states induced by static shear consolidation are affected by loading angles,which are enlarged by subsequent shear,consistent with the relationship between bidirectional shear and principal stresses.It provides evidence for the dissipation of stresses accompanying static liquefaction of granular materials.The presence of bi-directional principal stress rotation(PSR)is demonstrated,which evidences why the bi-directional shear of loading angles with components in two directions results in faster dissipations of stresses with static liquefaction.Contant volume shearing leads to cross-anisotropic stress and fabric at micro-contacts,but constant vertical stress shearing leads to complete anisotropic stress and fabric at micro-contacts.It explains the differentiating relationship between stress-strain responses and fabric anisotropy under these two conditions.Micromechanical signatures such as the slip state of micro-contacts and coordination number are also examined,providing further insights into understanding granular behaviour under bi-directional shear. 展开更多
关键词 Granular material Bi-directional shear Constant vertical stress Constant volume Principal stress rotation(PSR) ANISOTROPY
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A vertical track nonlinear energy sink 被引量:1
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作者 Meng LI Hu DING 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第6期931-946,共16页
Eliminating the effects of gravity and designing nonlinear energy sinks(NESs)that suppress vibration in the vertical direction is a challenging task with numerous damping requirements.In this paper,the dynamic design ... Eliminating the effects of gravity and designing nonlinear energy sinks(NESs)that suppress vibration in the vertical direction is a challenging task with numerous damping requirements.In this paper,the dynamic design of a vertical track nonlinear energy sink(VTNES)with zero linear stiffness in the vertical direction is proposed and realized for the first time.The motion differential equations of the VTNES coupled with a linear oscillator(LO)are established.With the strong nonlinearity considered of the VTNES,the steady-state response of the system is analyzed with the harmonic balance method(HBM),and the accuracy of the HBM is verified numerically.On this basis,the VTNES prototype is manufactured,and its nonlinear stiffness is identified.The damping effect and dynamic characteristics of the VTNES are studied theoretically and experimentally.The results show that the VTNES has better damping effects when strong modulation responses(SMRs)occur.Moreover,even for small-amplitude vibration,the VTNES also has a good vibration suppression effect.To sum up,in order to suppress the vertical vibration,an NES is designed and developed,which can suppress the vertical vibration within certain ranges of the resonance frequency and the vibration intensity. 展开更多
关键词 track nonlinear energy sink(TNES) vertical direction GRAVITY nonlinear stiffness harmonic balance method(HBM) vibration control
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