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Study on the pullout bearing characteristics of bio-inspired root piles in coral sand foundation under different root buried depths 认领 引用
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作者 Xiangwei Fang Yaoyi Zhang +4 位作者 Zhiqiang Wang Peixi Xiong Fenghui Hu Ganggang Zhou Chunyan Wang 《Biogeotechnics》 2026年第2期75-84,共10页
Bio-inspired root pile(abbreviated as root pile)is a new type of bio-inspired foundation,which has a broad application prospect in the development and construction of China's South China Sea area due to its good b... Bio-inspired root pile(abbreviated as root pile)is a new type of bio-inspired foundation,which has a broad application prospect in the development and construction of China's South China Sea area due to its good bearing characteristics such as pullout bearing capacity.The effect of root buried depth on the uplift bearing characteristics of root piles is analyzed through the model test of uplift bearing of root piles with different root buried depths in coral sand foundation.The results show that increasing the root buried depth can improve the ability of the root pile to control the uplift displacement,and there exists an optimal buried depth or range of buried depths that can effectively improve the pile foundation's uplift bearing capacity and control the ultimate displacement.The attenuation of axial force at the root is in the form of a step;with the increase of root buried depth,the maximum value of lateral friction resistance develops from the lower part of the pile body without root to the upper part of the pile body without root.The range of the bearing ratio of the root section of the pile with root buried depth of 260 mm,340mm and 420mm is 12.33%–15.68%,9.98%–17.82%and 7.61%–21.65%,respectively;the smaller the root buried depth is,the higher is the ratio of the bearing ratio of the root section at the beginning of loading,and the bigger the root buried depth is,the bigger is the ratio of the root's final bearing ratio.The change of soil pressure around the pile increases and then decreases,and the densest point of soil compacting moves upward with the increase of root buried depth.The research results provide scientific basis for the design of root pile buried depth and root arrangement in actual projects. 展开更多
关键词 Bio-inspired root piles (Root pile) Coral sand Pullout resistance Root buried depth Bearing characteristic
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Determination of focal depths for the 2024 M 7.3 Hualien offshore and 2025 M 6.2 Tainan earthquakes in Taiwan,China:An enhanced method based on sPn phase and waveform cross-correlation techniques 认领 引用
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作者 Huifang Chen Binhua Lin +2 位作者 Tairan Xu Yanming Zhang Yuanhong Yang 《Earthquake Research Advances》 CAS CSCD 2026年第1期17-24,共8页
This study proposes a method for determining earthquake focal depths by combining the sPn phase with the waveform cross-correlation technique,based on waveform data recorded by the Fujian Seismic Network from the 2024... This study proposes a method for determining earthquake focal depths by combining the sPn phase with the waveform cross-correlation technique,based on waveform data recorded by the Fujian Seismic Network from the 2024 M 7.3 Hualien offshore earthquake and the 2025 M 6.2 Tainan earthquake.The Pn phase onset was precisely aligned using waveform cross-correlation,and the arrival time difference(Δt)between the sPn and Pn phases was extracted via a sliding time-window correlation method.The focal depths were derived using a layered velocity model for the Taiwan region.Results show that the calculated focal depth for the Hualien earthquake is 23.1 km(Δt=6.9 s),with a relative error of 2.7%compared to the official result(22.5 km)from the Central Weather Administration of Taiwan.For the Tainan earthquake,the depth is 17.9 km(Δt=6.1 s),with a relative error of 13.3%.In this study,we show that a cross-correlation threshold of 0.8 and a bandpass filtering of 0.1–0.3 Hz are efficient to suppress noise and significantly improve depth accuracy for shallow earthquakes with depth<30 km.Compared to traditional travel-time location methods,this approach exhibits superior noise resistance and computational efficiency.Future work will focus on optimizing 3D velocity structures,integrating multiple phases,and applying deep learning techniques such as convolutional neural networks,aiming to improve the results in a more reliable and automatic way,and to provide efficient support on earthquake emergency response. 展开更多
关键词 M 7.3 Hualien earthquake M 6.2 Tainan earthquake sPn phase Focal depth Waveform cross-correlation Sliding time-window correlation method
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Spatial heterogeneity of groundwater depths in coastal cities and their responses to multiple factors interactions by interpretable machine learning models 认领 引用 被引量：2
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作者 Yuming Mo Jing Xu +5 位作者 Senlin Zhu Beibei Xu Jinran Wu Guangqiu Jin You-Gan Wang Ling Li 《Geoscience Frontiers》 SCIE CAS CSCD 2025年第3期223-241,共19页
Understanding spatial heterogeneity in groundwater responses to multiple factors is critical for water resource management in coastal cities.Daily groundwater depth(GWD)data from 43 wells(2018-2022)were collected in t... Understanding spatial heterogeneity in groundwater responses to multiple factors is critical for water resource management in coastal cities.Daily groundwater depth(GWD)data from 43 wells(2018-2022)were collected in three coastal cities in Jiangsu Province,China.Seasonal and Trend decomposition using Loess(STL)together with wavelet analysis and empirical mode decomposition were applied to identify tide-influenced wells while remaining wells were grouped by hierarchical clustering analysis(HCA).Machine learning models were developed to predict GWD,then their response to natural conditions and human activities was assessed by the Shapley Additive exPlanations(SHAP)method.Results showed that eXtreme Gradient Boosting(XGB)was superior to other models in terms of prediction performance and computational efficiency(R2>0.95).GWD in Yancheng and southern Lianyungang were greater than those in Nantong,exhibiting larger fluctuations.Groundwater within 5 km of the coastline was affected by tides,with more pronounced effects in agricultural areas compared to urban areas.Shallow groundwater(3-7 m depth)responded immediately(0-1 day)to rainfall,primarily influenced by farmland and topography(slope and distance from rivers).Rainfall recharge to groundwater peaked at 50%farmland coverage,but this effect was suppressed by high temperatures(>30℃)which intensified as distance from rivers increased,especially in forest and grassland.Deep groundwater(>10 m)showed delayed responses to rainfall(1-4 days)and temperature(10-15 days),with GDP as the primary influence,followed by agricultural irrigation and population density.Farmland helped to maintain stable GWD in low population density regions,while excessive farmland coverage(>90%)led to overexploitation.In the early stages of GDP development,increased industrial and agricultural water demand led to GWD decline,but as GDP levels significantly improved,groundwater consumption pressure gradually eased.This methodological framework is applicable not only to coastal cities in China but also could be extended to coastal regions worldwide. 展开更多
关键词 Groundwater depth Spatial heterogeneity Multiple influence factorsCoastal cities Machine Learning models SHAP values
A dual-attention embedded CNN model for estimating mixed layer depths in the Bay of Bengal 认领 引用
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作者 Wentao JIA Xun GONG +5 位作者 Shanliang ZHU Jifeng QI Xianmei ZHOU Hengkai YAO Xiang GONG Wenwu WANG 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2025年第4期1075-1092,共18页
Variations in ocean mixed layer depth(MLD)show a significant impact on energy balance in the global climate systems and marine ecosystems.At present,the accuracy of modeling MLD,especially in the region with complex o... Variations in ocean mixed layer depth(MLD)show a significant impact on energy balance in the global climate systems and marine ecosystems.At present,the accuracy of modeling MLD,especially in the region with complex ocean dynamics,remains a challenge,thus calling for an emergency using artificial intelligence approach to improve the assessment of the MLD.A novel convolutional neural network model was developed based on a dual-attention module(DA-CNN)to estimate the MLD in the Bay of Bengal(BoB)by integrating multi-source remote sensing data and Argo gridded data.Compared with the original CNN model,the DA-CNN model exhibits superior performance with notable improvements in the annual average root mean square error(RMSE)and R2 values by 13.0%and 8.4%,respectively,while more accurately capturing the seasonal variations in MLD.Moreover,the results using the DA-CNN model show minimum RMSE and maximum R2 values,in comparison to the calculation by the random forest,artificial neural network model,and the hybrid coordinate ocean model.Accordingly,our findings suggest that the newly developed DA-CNN model provides an effective advantage in studying the MLD and the associated ocean processes. 展开更多
关键词 mixed layer depth(MLD) remote sensing observation dual-attention module(DA-CNN) Bay of Bengal
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A Mooring System Deployment Design Methodology for Vessels at Varying Water Depths 认领 引用 被引量：3
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作者 XU Sheng-wen LIANG Ming-xiao +1 位作者 WANG Xue-feng DING Ai-bing 《China Ocean Engineering》 SCIE EI CSCD 2020年第2期185-197,共13页
In this paper,a methodology for designing mooring system deployment for vessels at varying water depths is proposed.The Non-dominated Sorting Genetic Algorithm-II(NSGA-II)is combined with a self-dependently developed ... In this paper,a methodology for designing mooring system deployment for vessels at varying water depths is proposed.The Non-dominated Sorting Genetic Algorithm-II(NSGA-II)is combined with a self-dependently developed vessel-mooring coupled program to find the optimal mooring system deployment considering both station-keeping requirements and the safety of the mooring system.Two case studies are presented to demonstrate the methodology by designing the mooring system deployments for a very large floating structure(VLFS)module and a semi-submersible platform respectively at three different water depths.It can be concluded from the obtained results that the mooring system can achieve a better station-keeping ability with relatively shorter mooring line when deployed in the shallow water.The safety factor of mooring line is mainly dominated by the maximum instantaneous tension increment in the shallow water,while the pre-tension has a decisive influence on the safety factor of the mooring line in the deep water. 展开更多
关键词 mooring system deployment design methodology NSGA-II varying water depths
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Focal depths and mechanisms of Tohoku-Oki aftershocks from teleseismic P wave modeling 认领 引用
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作者 Ling Bai Lorena Medina Luna +1 位作者 Eric A.Hetland Jeroen Ritsema 《Earthquake Science》 2014年第1期1-13,共13页
Aftershocks of the 2011 Tohoku-Oki great earthquake have a wide range of focal depths and fault plane mechanisms. We constrain the focal depths and focal mechanisms of 69 aftershocks with Mw 〉 5.4 by modeling the wav... Aftershocks of the 2011 Tohoku-Oki great earthquake have a wide range of focal depths and fault plane mechanisms. We constrain the focal depths and focal mechanisms of 69 aftershocks with Mw 〉 5.4 by modeling the waveforms of teleseismic P and its trailing near-surface reflections pP and sP. We find that the ＂thrust events＂ are within 10 krn from the plate interface. The dip angles of these thrust events increase with depth from ~ 5~ to ~ 25~. The ＂non-thrust events＂ vary from 60 km above to 40 km below the plate interface. Normal and strike-slip events within the overriding plate point to redistribution of stress following the primary great earthquake; however, due to the spatially variable stress change in the Tohoku-Oki earthquake, an understanding of how the mainshock affected the stresses that led to the aftershocks requires accurate knowledge of the aftershock location. 展开更多
关键词 Tohoku-Oki aftershocks Focal depths Focal mechanisms Coseismic stress change
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Nitrogen and Phosphorus Runoff Losses from Orchard Soils in South China as Affected by Fertilization Depths and Rates 认领 引用 被引量：27
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作者 ZENG Shu-Cai SU Zhi-Yao +2 位作者 CHEN Bei-Guang WU Qi-Tang OUYANG Ying 《Pedosphere》 SCIE CAS 2008年第1期45-53,共9页
Fertilizers are heavily applied in orchards of the hilly and mountainous topography of South China and may increase nutrient loadings to receiving waters.A simple runoff collecting system was used to measure the effec... Fertilizers are heavily applied in orchards of the hilly and mountainous topography of South China and may increase nutrient loadings to receiving waters.A simple runoff collecting system was used to measure the effects of different fertilization treatments on total N and P concentrations of surface runoff in a Chinese chestnut (Castanea mollissima Blume) orchard in Dongyuan County,Guangdong Province,China.In such orchards,fertilizer was typically applied in two short furrows or pits on either side of each tree.Treatments included three application depths (surface,10cm and 20 cm),and three application rates (low,median and high).Results showed that 90.5% of the runoff water samples had a total N concentration higher than 0.35 mgL-1 and 54.2% had a total P concentration higher than 0.1 mgL-1.Fertilizer application at all depths and at all but the lowest rate significantly increased total N and P concentrations in runoff water.Fertilization with chemical compound fertilizer at a soil depth of 20cm produced significantly lower (P<0.05) total N concentration in runoff than both surface and 10-cm depth fertilization,and significantly lower (P<0.05) total P concentration in runoff than surface fertilization.Total N and P concentrations in runoff significantly increased with the application rate of organic fertilizers.With the exception of total P concentrations,which were not significantly different between the control and fertilization at a rate of 119 kg P ha-1 in organic form,all the other fertilization treatments produced significantly higher total N and total P concentrations in runoff than the control.A fertilization depth≥20cm and an application rate≤72 kg N ha-1 or 119 kg P ha-1 for compound organic fertilizer was suggested to substantially reduce N and P runoff losses from hillslope orchards and to protect receiving waters in South China. 展开更多
关键词 fertilization depth fertilization rate runoff total N total P
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Responses of root growth of Alhagi sparsifolia Shap. (Fabaceae) to different simulated groundwater depths in the southern fringe of the Taklimakan Desert, China 认领 引用 被引量：18
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作者 FanJiang ZENG Cong SONG +5 位作者 HaiFeng GUO Bo LIU WeiCheng LUO DongWei GUI Stefan ARNDT DaLi GUO 《Journal of Arid Land》 SCIE CSCD 2013年第2期220-232,共13页
Alhagi sparsifolia Shap. （Fabaceae） is a spiny, perennial herb. The species grows in the salinized, arid regions in North China. This study investigated the response characteristics of the root growth and the dis- t... Alhagi sparsifolia Shap. （Fabaceae） is a spiny, perennial herb. The species grows in the salinized, arid regions in North China. This study investigated the response characteristics of the root growth and the dis- tribution of one-year-old A. sparsifolia seedlings to different groundwater depths in controlled plots. The eco- logical adaptability of the root systems of A. sparsifolia seedlings was examined using the artificial digging method. Results showed that： （1） A. sparsifolia seedlings adapted to an increase in groundwater depth mainly through increasing the penetration depth and growth rate of vertical roots. The vertical roots grew rapidly when soil moisture content reached 3%-9%, but slowly when soil moisture content was 13%-20%. The vertical roots stopped growing when soil moisture content reached 30% （the critical soil moisture point）. （2） The morphological plasticity of roots is an important strategy used by A. sparsifolia seedlings to obtain water and adapt to dry soil conditions. When the groundwater table was shallow, horizontal roots quickly expanded and tillering increased in order to compete for light resources, whereas when the groundwater table was deeper, vertical roots developed quickly to exploit space in the deeper soil layers. （3） The decrease in groundwater depth was probably respon- sible for the root distribution in the shallow soil layers. Root biomass and surface area both decreased with soil depth. One strategy of A. sparsifolia seedlings in dealing with the increase in groundwater depth is to increase root biomass in the deep soil layers. The relationship between the root growth/distribution of A. sparsifolia and the depth of groundwater table can be used as guidance for harvesting A. sparsifolia biomass and managing water resources for forage grasses. It is also of ecological significance as it reveals how desert plants adapt to arid environments. 展开更多
关键词 Alhagi sparsifolia Shap. simulated groundwater depth root system growth and distribution ecological adaptability root morphological plasticity
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Estimating distribution of water uptake with depth of winter wheat by hydrogen and oxygen stable isotopes under different irrigation depths 认领 引用 被引量：15
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作者 GUO Fei MA Juan-juan +3 位作者 ZHENG Li-jian SUN Xi-huan GUO Xiang-hong ZHANG Xue-lan 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2016年第4期891-906,共16页
Crop root system plays an important role in the water cycle of the soil-plant-atmosphere continuum. In this study, com- bined isotope techniques, root length density and root cell activity analysis were used to invest... Crop root system plays an important role in the water cycle of the soil-plant-atmosphere continuum. In this study, com- bined isotope techniques, root length density and root cell activity analysis were used to investigate the root water uptake mechanisms of winter wheat （Triticum aesfivum L.） under different irrigation depths in the North China Plain. Both direct inference approach and multisource linear mixing model were applied to estimate the distribution of water uptake with depth in six growing stages. Results showed that winter wheat under land surface irrigation treatment （Ts） mainly absorbed water from 10-20 cm soil layers in the wintering and green stages （66.9 and 72.0%, respectively）; 0-20 cm （57.0%） in the jointing stage; 0-40 （15.3%） and 80-180 cm （58.1%） in the heading stage; 60-80 （13.2%） and 180-220 cm （35.5%） in the filling stage; and 0-40 （46.8%） and 80-100 cm （31.0%） in the ripening stage. Winter wheat under whole soil layers irrigation treatment （Tw） absorbed more water from deep soil layer than Ts in heading, filling and ripening stages. Moreover, root cell activity and root length density of winter wheat under TW were significantly greater than that of Ts in the three stages. We concluded that distribution of water uptake with depth was affected by the availability of water sources, the root length density and root cell activity. Implementation of the whole soil layers irrigation method can affect root system distribution and thereby increase water use from deeper soil and enhance water use efficiency. 展开更多
关键词 hydrogen and oxygen stable isotopes multisource linear mixing model winter wheat distribution of wateruptake with depth
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Predicting excavation damage zone depths in brittle rocks 认领 引用 被引量：33
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作者 Matthew A.Perras Mark S.Diederichs 《Journal of Rock Mechanics and Geotechnical Engineering》 CSCD 2016年第1期60-74,共15页
During the construction of an underground excavation, damage occurs in the surrounding rock mass due in large part to stress changes. While the predicted damage extent impacts profile selection and support design, the... During the construction of an underground excavation, damage occurs in the surrounding rock mass due in large part to stress changes. While the predicted damage extent impacts profile selection and support design, the depth of damage is a critical aspect for the design of permeability sensitive excavations, such as a deep geological repository(DGR) for nuclear waste. Review of literature regarding the depth of excavation damage zones(EDZs) indicates three zones are common and typically related to stress induced damage. Based on past developments related to brittle damage prediction using continuum modelling, the depth of the EDZs has been examined numerically. One method to capture stress induced damage in conventional engineering software is the damage initiation and spalling limit(DISL) approach. The variability of depths predicted using the DISL approach has been evaluated and guidelines are suggested for determining the depth of the EDZs around circular excavations in brittle rock masses. Of the inputs evaluated, it was found that the tensile strength produces the greatest variation in the depth of the EDZs. The results were evaluated statistically to determine the best fit relation between the model inputs and the depth of the EDZs. The best correlation and least variation were found for the outer EDZ and the highly damaged zone(HDZ) showed the greatest variation. Predictive equations for different EDZs have been suggested and the maximum numerical EDZ depths, represented by the 68% prediction interval, agreed well with the empirical evidence. This suggests that the numerical limits can be used for preliminary depth prediction of the EDZs in brittle rock for circular excavations. 展开更多
关键词 Excavation damage zones(EDZs) Deep geological repository(DGR) Empirical depth prediction Numerical depth prediction Damage depth sensitivity Damage initiation and spalling limit(DISL)
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Characteristic strength and acoustic emission properties of weakly cemented sandstone at different depths under uniaxial compression 认领 引用 被引量：5
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作者 Bin Liu Yixin Zhao +3 位作者 Cun Zhang Jinlong Zhou Yutao Li Zhuang Sun 《International Journal of Coal Science & Technology》 EI CAS CSCD 2021年第6期1288-1301,共14页
As coal mining is extended from shallow to deep areas along the western coalfield,it is of great significance to study weakly cemented sandstone at different depths for underground mining engineering.Sandstones from d... As coal mining is extended from shallow to deep areas along the western coalfield,it is of great significance to study weakly cemented sandstone at different depths for underground mining engineering.Sandstones from depths of 101.5,203.2,317.3,406.9,509.9 and 589.8 m at the Buertai Coal Mine were collected.The characteristic strength,acoustic emission(AE),and energy evolution of sandstone during uniaxial compression tests were analyzed.The results show that the intermediate frequency(125-275 kHz)of shallow rock mainly occurs in the postpeak stage,while deep rock occurs in the prepeak stage.The initiation strength and damage strength of the sandstone at different depths range from 0.23 to 0.50 and 0.63 to 0.84 of peak strength(σc),respectively,decrease exponentially and are a power function with depth.The precursor strength ranges from 0.88σcto 0.99σc,increases with depth before reaching a depth of 300 m,and tends to stabilize after 300 m.The ratio of the initiation strength to the damage strength(k)ranges from 0.25 to 0.62 and decreases exponentially with depth.The failure modes of sandstone at different depths are tension-dominated mixed tensile-shear failure.Shear failure mainly occurs at the unstable crack propagation stage.The count of the shear failure bands before the peak strength increases gradually,and increases first and then decreases after the peak strength with burial depth.The cumulative input energy,released elastic energy and dissipated energy increase with depth.The elastic release rate ranges from 0.46×10-3to 198.57×10-3J/(cm3s)and increases exponentially with depth. 展开更多
关键词 Burial depth Weakly cemented sandstone Acoustic emission(AE) Characteristic strength Energy evolution Failure mode
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Changes in the depths of seasonal freezing and thawing and their effects on vegetation in the Three-River Headwater Region of the Tibetan Plateau 认领 引用 被引量：6
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作者 WANG Rui DONG Zhi-bao ZHOU Zheng-chao 《Journal of Mountain Science》 SCIE CSCD 2019年第12期2810-2827,共18页
Frozen ground degradation plays an important role in vegetation growth and activity in high-altitude cold regions.This study estimated the spatiotemporal variations in the active layer thickness(ALT)of the permafrost ... Frozen ground degradation plays an important role in vegetation growth and activity in high-altitude cold regions.This study estimated the spatiotemporal variations in the active layer thickness(ALT)of the permafrost region and the soil freeze depth(SFD)in the seasonally frozen ground region across the Three Rivers Source Region(TRSR)from 1980 to 2014 using the Stefan equation,and differentiated the effects of these variations on alpine vegetation in these two regions.The results showed that the average ALT from 1980 to 2014 increased by23.01 cm/10 a,while the average SFD decreased by 3.41 cm/10 a,and both changed intensively in the transitional zone between the seasonally frozen ground and permafrost.From 1982-2014,the increase in the normalized difference vegetation index(NDVI)and the advancement of the start of the vegetation growing season(SOS)in the seasonally frozen ground region(0.0078/10 a,1.83 d/10 a)were greater than those in the permafrost region(0.0057/10 a,0.39 d/10 a).The results of the correlation analysis indicated that increases in the ALT and decreases in the SFD in the TRSR could lead to increases in the NDVI and advancement of the SOS.Surface soil moisture played a critical role in vegetation growth in association with the increasing ALT and decreasing SFD.The NDVI for all vegetation types in the TRSR except for alpine vegetation showed an increasing trend that was significantly related to the SFD and ALT.During the study period,the general frozen ground conditions were favorable to vegetation growth,while the average contributions of ALT and SFD to the interannual variation in the NDVI were greater than that of precipitation but less than that of temperature. 展开更多
关键词 Frozen soil depth Active layer thickness Alpine vegetation Climate warming Three Rivers Source Region
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Numerical Simulation and Experimental Research on Hydrodynamic Performance of Propeller with Varying Shaft Depths 认领 引用 被引量：4
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作者 郭春雨 赵大刚 孙瑜 《China Ocean Engineering》 SCIE EI CSCD 2014年第2期271-282,共12页
In order to study hydrodynamic performance of a propeller in the free surface, the numerical simulation and open-water experiments are carried out with varying shaft depths of propeller. The influences of shaft depths... In order to study hydrodynamic performance of a propeller in the free surface, the numerical simulation and open-water experiments are carried out with varying shaft depths of propeller. The influences of shaft depths of a propeller on thrust and torque coefficient in calm water are mainly studied. Meanwhile, this paper also studies the propeller air-ingestion under special working conditions by experiment and theoretical calculation method, and compares the calculation results and experimental results. The results prove that the theoretical calculation model used in this paper can imitate the propeller air-ingestion successfully. The successful phenomenon simulation provides an essential theoretical basis to understand the physical essence of the propeller air-ingestion. 展开更多
关键词 propulsive performance depth of propeller shaft free surface air-ingestion
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Coin-structured tunable beam shaping assembly design for accelerator-based boron neutron capture therapy for tumors at different depths and sizes 认领 引用 被引量：3
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作者 Zhao‑Peng Qiao Yao‑Cheng Hu +5 位作者 Quan‑Xu Jiang Jing‑Jing Fan Isao Murata Rui‑Rui Liu Bo Wang Sheng Wang 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2023年第12期66-76,共11页
In the past decade,boron neutron capture therapy utilizing an accelerator-based neutron source(ABNS)designed primarily for producing epithermal neutrons has been implemented in the treatment of brain tumors and other ... In the past decade,boron neutron capture therapy utilizing an accelerator-based neutron source(ABNS)designed primarily for producing epithermal neutrons has been implemented in the treatment of brain tumors and other cancers.The specifications for designing an epithermal beam are primarily based on the IAEA-TECODC-1223 report,issued in 2001 for reactor neutron sources.Based on this report,the latest perspectives and clinical requirements,we designed an ABNS capable of adjusting the average neutron beam energy.The design was based on a 2.8 MeV,20 mA proton beam bombarding a lithium target to produce neutrons that were subsequently moderated and tuned through a tunable beam shaping assembly(BSA)which can modify the thicknesses and materials of the coin-shaped moderators,back reflectors,filters,and collimators.The simulation results demonstrated that epithermal neutron beams for deep seated tumor treatment,which were generated by utilizing magnesium fluoride with lengths ranging between 28 and 36 cm as the moderator,possessed a treatment depth of 5.6 cm although the neutron flux peak shifts from 4.5 to 1.0 keV.When utilizing a thinner moderator,a less accelerated beam power can meet the treatment requirements.However,higher powers reduced the treatment time.In contrast,employing a thick moderator can reduce the skin dose.In scenarios that required relatively low energy neutron beams,the removal of the thermal neutron filter can raise the thermal neutron flux at the beam port.And the depth of the dose rate peak could be adjusted between 0.25 and 2.20 cm by combining magnesium fluoride and polyethylene coins of different thicknesses.Hence,this device has a better adaptability for the treatment of superficial tumors.Overall,the tunable BSA provides greater flexibility for clinical treatment than common BSA designs that can only adjust the port size. 展开更多
关键词 Boron neutron capture therapy(BNCT) Accelerator-based neutron source(ABNS) Beam shaping assembly(BSA) Treatment depth
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Improved tilt-depth method for fast estimation of top and bottom depths of magnetic bodies 认领 引用 被引量：2
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作者 王彦国 张瑾 +2 位作者 葛坤朋 陈晓 聂逢君 《Applied Geophysics》 SCIE CSCD 2016年第2期249-256,416,共8页
The tilt-depth method can be used to make fast estimation of the top depth of magnetic bodies. However, it is unable to estimate bottom depths and its every inversion point only has a single solution. In order to reso... The tilt-depth method can be used to make fast estimation of the top depth of magnetic bodies. However, it is unable to estimate bottom depths and its every inversion point only has a single solution. In order to resolve such weaknesses, this paper presents an improved tilt-depth method based on the magnetic anomaly expression of vertical contact with a finite depth extent, which can simultaneously estimate top and bottom depths of magnetic bodies. In addition, multiple characteristic points are selected on the tilt angle map for joint computation to improve reliability of inversion solutions. Two- and three- dimensional model tests show that this improved tilt-depth method is effective in inverting buried depths of top and bottom bodies, and has a higher inversion precision for top depths than the conventional method. The improved method is then used to process aeromagnetic data over the Changling Fault Depression in the Songliao Basin, and inversion results of top depths are found to be more accurate for actual top depths of volcanic rocks in two nearby drilled wells than those using the conventional tilt-depth method. 展开更多
关键词 Tilt-depth method Buried depth Changling Fault Depression Volcanic rocks
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The focusing performance with a horizontal time-reversal array at different depths in shallow water 认领 引用 被引量：3
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作者 张同伟 杨坤德 马远良 《Chinese Physics B》 SCIE EI CAS 2010年第12期347-355,共9页
The performance of time-reversal focusing with a horizontal line array at different depths is investigated by normal mode modeling and computer simulation. It is observed that the focusing performance of a bottom-moun... The performance of time-reversal focusing with a horizontal line array at different depths is investigated by normal mode modeling and computer simulation. It is observed that the focusing performance of a bottom-mounted horizontal time-reversal array is much better than that of a horizontal time-reversal array at other depths in shallow water. The normal mode modeling is used to explain this result. The absolute values of the modes at different depths are compared. It is shown that the number of modes whose absolute values close to zero is smaller at the bottom than that at other depths. It means that the horizontal time-reversal array deployed at the bottom can sample more modes, obtain more information of the probe source and achieve better focusing performance. The numerical simulations of time-reversal focusing performance under various conditions, such as different sound speed profiles, and different bottom parameters, lead to similar results. 展开更多
关键词 time-reversal horizontal line array array depth
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Survival,growth and immune activity of scallop Chlamys farreri cultured at different depths in Haizhou Bay(Yellow Sea,China) during hot season 认领 引用 被引量：2
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作者 于宗赫 杨红生 +3 位作者 刘保忠 邢坤 张立斌 许强 《Chinese Journal of Oceanology and Limnology》 2010年第3期498-507,共10页
Survival, growth and immune response of the scallop, Chlamys farreri, cultured in lantern nets at five different depths (2, 5, 10, 15, and 20 m below the sea surface) were studied in Haizhou Bay during the hot season ... Survival, growth and immune response of the scallop, Chlamys farreri, cultured in lantern nets at five different depths (2, 5, 10, 15, and 20 m below the sea surface) were studied in Haizhou Bay during the hot season (summer and autumn) of 2007. Survival and growth rates were quantified bimonthly. Immune activities in hemolymph (superoxide dismutase (SOD) and acid phosphatase (ACP)) were measured to evaluate the health of scallops at the end of the study. Environmental parameters at the five depths were also monitored during the experiment. Mortalities mainly occurred during summer. Survival of scallops suspended at 15 m (78.0%) and 20 m (86.7%) was significantly higher than at 2 m (62.9%), 5 m (60.8%) or 10 m (66.8%) at the end of the study. Mean shell height grew significantly faster at 10 m (205.0 μm/d) and 20 m (236.9 μm/d) than at 2, 5 or 15 m in summer (July 9 to September 1); however, shell growth rate at 20 m was significantly lower than at the other four depths in autumn (September 2 to November 6). In contrast to summer, scallops at 5 m grew faster (262.9 μm/d) during autumn. The growth of soft tissue at different depths showed a similar trend to the shell. Growth rates of shell height and soft tissue were faster in autumn than in summer, with the exception of shell height at 20 m. SOD activity of scallops increased with depth, and ACP activity was significantly higher at 15 and 20 m than at other depths, which suggests that scallops were healthier near the bottom. Factors explaining the depth-related mortality and growth of scallops are also discussed. We conclude that the mass mortality of scallop, C. farreri, during summer can be prevented by moving the culture area to deeper water and yield can be maximized by suspending the scallops in deep water during summer and then transferring them to shallow water in autumn. 展开更多
关键词 Chlamysfarreri survival growth mortality immune activity hot season water depth
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Measurement of the depths at different regions of the anterior chamber in healthy Chinese adults 认领 引用 被引量：1
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作者 Yuan Zong Qing-Chen Li +3 位作者 Huan Xu Jian Yu Chun-Hui Jiang Xing-Huai Sun 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2020年第1期135-140,共6页
AIM: To measure the depths of different regions of the anterior chamber(AC) in healthy Chinese adults, and to explore possible correlations with age or gender.METHODS: The AC was imaged by swept-source optical coheren... AIM: To measure the depths of different regions of the anterior chamber(AC) in healthy Chinese adults, and to explore possible correlations with age or gender.METHODS: The AC was imaged by swept-source optical coherence tomography in healthy Chinese adults. The horizontal scan of the right eye was used to measure the anterior chamber depth(ACD) at 199 points.RESULTS: A total of 309 images from 309 subjects were analyzed. The ACD values at nearly all locations were negatively correlated with age(all P<0.05), except for ACD1, 2, 198, and 199(correspond to the iris roots). The mean annual decrease 0.013±0.005 mm/y for all ACDs combined, 0.008±0.004 mm/y for the peripheral region, 0.017±0.003 mm/y for the middle peripheral region, and 0.014±0.001 mm/y for the central region. The mean annual decrease was significantly different among these three regions(P<0.001). The ACD was greater in males than in females(P<0.05). The mean difference in ACD between males and females was 0.081±0.025 mm.CONCLUSION: This study showed that optical coherence tomography can be used to measure the ACD of different regions of the AC. We found reductions in ACD with age, although the reduction varied among different points, in healthy Chinese adults. 展开更多
关键词 optical coherence tomography anterior chamber depth age gender anterior chamber
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Experimental Investigation on Vortex-Induced Vibration of Deep-Sea Risers of Different Excitation Water Depths 认领 引用 被引量：1
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作者 LI Peng DONG Zheng-kai +4 位作者 LIU Yu WANG Yu CONG Ai-jun GUO Haiyan FU Qiang 《China Ocean Engineering》 SCIE EI CSCD 2021年第2期215-227,共13页
The vortex-induced vibration test of the deep-sea riser was carried out with different excitation water depths in the wave-current combined water flume.By dimensionally changing the multi-stage water depth and hydrody... The vortex-induced vibration test of the deep-sea riser was carried out with different excitation water depths in the wave-current combined water flume.By dimensionally changing the multi-stage water depth and hydrodynamic parameters such as outflow velocity at various water depths,the dynamic response parameters such as dominant frequency,dimensionless displacement and vibration trajectory evolution process of the riser under different excitation water depths were explored to reveal the sensitive characteristics of the dynamic response of vortexinduced vibration of the risers under different excitation water depths.The results show that different excitation water depths will change the additional mass of the riser and the fluid damping and other parameters,which will affect the spatial correlation and stability of the vortex shedding behind the riser.In the lock-in region,the distribution range of the characteristic frequency becomes narrow and centered on the lock-in frequency.The increase of the excitation water depth gradually advances the starting point of the lock-in region of the riser,and at the same time promotes the excitation of the higher-order vibration frequency of the riser structure.Within the dimensionless excitation water depth,the dominant frequency and dimensionless displacement are highly insensitive to the excitation water depth at high flow velocity.The change of the excitation water depth will interfere with the correlation of the non-linear coupling of the riser.The“8-shaped”gradually becomes irregular,and the vibration trajectories of the riser show“O-shape”,“X-shape”and“Crescent-shape”. 展开更多
关键词 deep-sea riser excitation water depth vortex-induced vibration(VIV) dynamic response coupling effect
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An Efficient Model for Transient Surface Waves in Both Finite and Infinite Water Depths 认领 引用 被引量：1
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作者 宁德志 滕斌 +1 位作者 臧军 柳淑学 《China Ocean Engineering》 SCIE EI 2009年第3期459-472,共14页
A numerical model is developed to simulate fully nonlinear extreme waves in finite and infinite water-depth wave tanks. A semi-mixed Enlerian-Lagrangian formulation is adopted and a higher-order boundary element metho... A numerical model is developed to simulate fully nonlinear extreme waves in finite and infinite water-depth wave tanks. A semi-mixed Enlerian-Lagrangian formulation is adopted and a higher-order boundary element method in conjunction with an image Green function is used for the fluid domain. The botmdary values on the free surface are updated at each time step by a fourth-order Runga-Kutta time-marching scheme at each time step. Input wave characteristics are specified at the upstream boundary by an appropriate wave theory. At the downstream boundary, an artificial damping zone is used to prevent wave reflection back into the computational domain. Using the image Green function in the whole fluid domain, the integrations on the two lateral walls and bottom are excluded. The simulation results on extreme wave elevations in finite and infinite water-depths are compared with experimental results and second-order analytical solutions respectively. The wave kinematics is also discussed in the present study. 展开更多
关键词 focused waves fully nonlinear higher-order boundary element method image Green function infinite water depth
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