The near-seabed multichannel seismic exploration systems have yielded remarkable successes in marine geological disaster assessment,marine gas hydrate investigation,and deep-sea mineral exploration owing to their high...The near-seabed multichannel seismic exploration systems have yielded remarkable successes in marine geological disaster assessment,marine gas hydrate investigation,and deep-sea mineral exploration owing to their high vertical and horizontal resolution.However,the quality of deep-towed seismic imaging hinges on accurate source-receiver positioning information.In light of existing technical problems,we propose a novel array geometry inversion method tailored for high-resolution deep-towed multichannel seismic exploration systems.This method is independent of the attitude and depth sensors along a deep-towed seismic streamer,accounting for variations in seawater velocity and seabed slope angle.Our approach decomposes the towed line array into multiline segments and characterizes its geometric shape using the line segment distance and pitch angle.Introducing optimization parameters for seawater velocity and seabed slope angle,we establish an objective function based on the model,yielding results that align with objective reality.Employing the particle swarm optimization algorithm enables synchronous acquisition of optimized inversion results for array geometry and seawater velocity.Experimental validation using theoretical models and practical data verifies that our approach effectively enhances source and receiver positioning inversion accuracy.The algorithm exhibits robust stability and reliability,addressing uncertainties in seismic traveltime picking and complex seabed topography conditions.展开更多
Graphene oxide(GO) channels exhibit unique mass transport behaviors due to their flexibility, controllable thinness and extraordinary physicochemical properties, enabling them to be widely used for adsorption and memb...Graphene oxide(GO) channels exhibit unique mass transport behaviors due to their flexibility, controllable thinness and extraordinary physicochemical properties, enabling them to be widely used for adsorption and membrane separation. Nevertheless, the adsorption behavior of nanosized contaminants within the channels of GO membrane has not been fully discussed. In this study, we fabricated a GO membrane(PGn, where n represents the deposition cycles of GO) with multi channels via the crosslinking of GO and multibranched poly(ethyleneimine)(PEI). Phenol was used as molecular probe to determine the correlations between dynamic adsorption behavior and structural parameters of the multilevel GO/PEI membrane. PG8 shows higher adsorption capacities and affinity, which is predominantly attributed to the multichannel structure providing a large specific surface for phenol adsorption, enhancing the accessibility of active sites for phenol molecules and the transport of phenol. Density functional theory calculations demonstrate that the adsorption mechanism of phenol within GO channel is energetically oriented by hydrogen bonds, which is dominated by oxygen-containing groups compared to amino groups. Particularly, the interfaces which facilitate strong π-π interaction and hydrogen bonds maybe the most active regions. Moreover, the as-prepared PG8 membrane showed outstanding performance for other contaminants such as methyl orange and Cr(VI). It is anticipated that this study will have implications for design of GO-related environmental materials with enhanced efficiency.展开更多
Three-dimensional(3D)printing technology is expected to solve the organ shortage problem.However,owing to the accuracy limitations,it is difficult for the current bioprinting technology to achieve an accurate control ...Three-dimensional(3D)printing technology is expected to solve the organ shortage problem.However,owing to the accuracy limitations,it is difficult for the current bioprinting technology to achieve an accurate control of the spatial position and distribution of a single cell or single component droplet.In this study,to accurately achieve the directional deposition of different cells and biological materials in the spatial position for the construction of large transplantable tissues and organs,a high-precision multichannel 3D bioprinter with submicron-level motion accuracy is designed,and concurrent and synergistic printing methods are proposed.Based on the high-precision motion characteristics of the gantry structure and the requirements of concurrent and synergistic printing,a 3D bioprint-ing system with a set of 6 channels is designed to achieve six-in-one printing.Based on the Visual C++environ-ment,a control system software that integrates the programmable multi-axis controller(PMAC)motion,pneumatic,and temperature control subsystems was developed and designed.Finally,based on measurements and experiments,the 3D bioprinter and its control system was verified to fulfil the requirements of multichannel,concurrent,and syn-ergistic printing with submicron-level motion accuracy,significantly shortening the printing time and improving the printing efficiency.This study not only provides an equipment basis for printing complex heterogeneous tissue structures,but also improves the flexibility and functionality of bioprinting,and ultimately makes the construction of complex multicellular tissues or organs possible.展开更多
BACKGROUND Among the various types of aortic dissection,multichanneled aortic dissection(MCAD)differs from classic double-channeled aortic dissection and involves the formation of an additional false lumen in the aort...BACKGROUND Among the various types of aortic dissection,multichanneled aortic dissection(MCAD)differs from classic double-channeled aortic dissection and involves the formation of an additional false lumen in the aortic wall or the flaps.It is considered a relatively rare condition with high perioperative mortality and morbidity.However,the morphological characteristic and the optimal therapeutic strategy for MCAD has not been fully determined.CASE SUMMARY A 64-year-old man presented to our hospital with severe epigastric abdominal pain radiating to the back that was associated with nausea without emesis.A computed tomography angiogram was performed that revealed a type B aortic dissection with multiple channels extending from the level of the left subclavian artery to the bilateral femoral arteries.We used a medical three-dimensional modeling(3D)modeling system to identify the location and extension of multiple lumens from different angles.It also precisely located the two primary entries leading to the false lumens,which helped us to exclude the two false lumens with one stent-graft.CONCLUSION By applying medical 3D modeling system,we discover the fragility of aortic wall and the collapse of true lumen caused by the multiple false lumens are the two morphological features of MCAD.展开更多
针对大数据环境下并行K-means算法存在的面对高维数据聚类效果差、数据分区不均匀、初始质心敏感等问题,提出了一种基于MapReduce和MSSA的并行K-means算法MR-MSKCA。首先,提出基于肯德尔相关系数和深度稀疏自动编码器的降维策略(dimensi...针对大数据环境下并行K-means算法存在的面对高维数据聚类效果差、数据分区不均匀、初始质心敏感等问题,提出了一种基于MapReduce和MSSA的并行K-means算法MR-MSKCA。首先,提出基于肯德尔相关系数和深度稀疏自动编码器的降维策略(dimensionality reduction strategy based on Kendall correlation coefficient and DSAE,DRKCAE)对高维数据进行特征加权和特征提取,解决了高维数据不相关特征和结构稀疏导致的聚类效果差的问题;其次,提出基于两段映射的广义超平面分区策略(uniform partition strategy based on two-stage mapping,UPS)对数据集进行划分,获取均匀的数据分区;最后提出非均匀变异麻雀搜索算法(non-uniform mutation sparrow search algorithm,MSSA)用于获取并行K-means的聚类质心,解决了算法初始质心敏感的问题。在UCI数据集上进行的实验显示,MR-MSKCA较MR-KNMF、MR-PGDLSH、MR-GAPKCA的运行时间分别降低了45.1%、49.1%、59.8%,聚类效果分别提升了19.2%、22.8%、24%,表明MR-MSKCA对大数据进行聚类时有良好性能,适用于不同场景的大数据聚类分析。展开更多
Earth＇s variable rotation is mainly produced by the variability of the AAM（atmospheric angular momentum）. In particular, the axial AAM component X_3, which undergoes especially strong variations,induces changes in ...Earth＇s variable rotation is mainly produced by the variability of the AAM（atmospheric angular momentum）. In particular, the axial AAM component X_3, which undergoes especially strong variations,induces changes in the Earth＇s rotation rate. In this study we analysed maps of regional input into the effective axial AAM from 1948 through 2011 from NCEP/NCAR reanalysis. Global zonal circulation patterns related to the LOD（length of day） were described. We applied MSSA（Multichannel Singular Spectrum Analysis） jointly to the mass and motion components of AAM, which allowed us to extract annual, semiannual, 4-mo nth, quasi-biennial, 5-year, and low-frequency oscillations. PCs（Principal components） strongly related to ENSO（El Nino southern oscillation） were released. They can be used to study ENSO-induced changes in pressure and wind fields and their coupling to LOD. The PCs describing the trends have captured slow atmospheric circulation changes possibly related to climate variability.展开更多
基金supported by the special funds of Laoshan Laboratory(No.LSKJ202203604)the National Key Research and Development Program of China(No.2016 YFC0303901).
文摘The near-seabed multichannel seismic exploration systems have yielded remarkable successes in marine geological disaster assessment,marine gas hydrate investigation,and deep-sea mineral exploration owing to their high vertical and horizontal resolution.However,the quality of deep-towed seismic imaging hinges on accurate source-receiver positioning information.In light of existing technical problems,we propose a novel array geometry inversion method tailored for high-resolution deep-towed multichannel seismic exploration systems.This method is independent of the attitude and depth sensors along a deep-towed seismic streamer,accounting for variations in seawater velocity and seabed slope angle.Our approach decomposes the towed line array into multiline segments and characterizes its geometric shape using the line segment distance and pitch angle.Introducing optimization parameters for seawater velocity and seabed slope angle,we establish an objective function based on the model,yielding results that align with objective reality.Employing the particle swarm optimization algorithm enables synchronous acquisition of optimized inversion results for array geometry and seawater velocity.Experimental validation using theoretical models and practical data verifies that our approach effectively enhances source and receiver positioning inversion accuracy.The algorithm exhibits robust stability and reliability,addressing uncertainties in seismic traveltime picking and complex seabed topography conditions.
基金supported by the National Natural Science Foundation of China(22078269 and 51708406).
文摘Graphene oxide(GO) channels exhibit unique mass transport behaviors due to their flexibility, controllable thinness and extraordinary physicochemical properties, enabling them to be widely used for adsorption and membrane separation. Nevertheless, the adsorption behavior of nanosized contaminants within the channels of GO membrane has not been fully discussed. In this study, we fabricated a GO membrane(PGn, where n represents the deposition cycles of GO) with multi channels via the crosslinking of GO and multibranched poly(ethyleneimine)(PEI). Phenol was used as molecular probe to determine the correlations between dynamic adsorption behavior and structural parameters of the multilevel GO/PEI membrane. PG8 shows higher adsorption capacities and affinity, which is predominantly attributed to the multichannel structure providing a large specific surface for phenol adsorption, enhancing the accessibility of active sites for phenol molecules and the transport of phenol. Density functional theory calculations demonstrate that the adsorption mechanism of phenol within GO channel is energetically oriented by hydrogen bonds, which is dominated by oxygen-containing groups compared to amino groups. Particularly, the interfaces which facilitate strong π-π interaction and hydrogen bonds maybe the most active regions. Moreover, the as-prepared PG8 membrane showed outstanding performance for other contaminants such as methyl orange and Cr(VI). It is anticipated that this study will have implications for design of GO-related environmental materials with enhanced efficiency.
基金Supported by National Key Research and Development Program of China(Grant No.2018YFA0703000)National Natural Science Foundation of China(Grant No.51875518)Fundamental Research Funds for the Central Universities of China(Grant Nos.2019XZZX003-02,2019FZA4002).
文摘Three-dimensional(3D)printing technology is expected to solve the organ shortage problem.However,owing to the accuracy limitations,it is difficult for the current bioprinting technology to achieve an accurate control of the spatial position and distribution of a single cell or single component droplet.In this study,to accurately achieve the directional deposition of different cells and biological materials in the spatial position for the construction of large transplantable tissues and organs,a high-precision multichannel 3D bioprinter with submicron-level motion accuracy is designed,and concurrent and synergistic printing methods are proposed.Based on the high-precision motion characteristics of the gantry structure and the requirements of concurrent and synergistic printing,a 3D bioprint-ing system with a set of 6 channels is designed to achieve six-in-one printing.Based on the Visual C++environ-ment,a control system software that integrates the programmable multi-axis controller(PMAC)motion,pneumatic,and temperature control subsystems was developed and designed.Finally,based on measurements and experiments,the 3D bioprinter and its control system was verified to fulfil the requirements of multichannel,concurrent,and syn-ergistic printing with submicron-level motion accuracy,significantly shortening the printing time and improving the printing efficiency.This study not only provides an equipment basis for printing complex heterogeneous tissue structures,but also improves the flexibility and functionality of bioprinting,and ultimately makes the construction of complex multicellular tissues or organs possible.
文摘BACKGROUND Among the various types of aortic dissection,multichanneled aortic dissection(MCAD)differs from classic double-channeled aortic dissection and involves the formation of an additional false lumen in the aortic wall or the flaps.It is considered a relatively rare condition with high perioperative mortality and morbidity.However,the morphological characteristic and the optimal therapeutic strategy for MCAD has not been fully determined.CASE SUMMARY A 64-year-old man presented to our hospital with severe epigastric abdominal pain radiating to the back that was associated with nausea without emesis.A computed tomography angiogram was performed that revealed a type B aortic dissection with multiple channels extending from the level of the left subclavian artery to the bilateral femoral arteries.We used a medical three-dimensional modeling(3D)modeling system to identify the location and extension of multiple lumens from different angles.It also precisely located the two primary entries leading to the false lumens,which helped us to exclude the two false lumens with one stent-graft.CONCLUSION By applying medical 3D modeling system,we discover the fragility of aortic wall and the collapse of true lumen caused by the multiple false lumens are the two morphological features of MCAD.
文摘针对大数据环境下并行K-means算法存在的面对高维数据聚类效果差、数据分区不均匀、初始质心敏感等问题,提出了一种基于MapReduce和MSSA的并行K-means算法MR-MSKCA。首先,提出基于肯德尔相关系数和深度稀疏自动编码器的降维策略(dimensionality reduction strategy based on Kendall correlation coefficient and DSAE,DRKCAE)对高维数据进行特征加权和特征提取,解决了高维数据不相关特征和结构稀疏导致的聚类效果差的问题;其次,提出基于两段映射的广义超平面分区策略(uniform partition strategy based on two-stage mapping,UPS)对数据集进行划分,获取均匀的数据分区;最后提出非均匀变异麻雀搜索算法(non-uniform mutation sparrow search algorithm,MSSA)用于获取并行K-means的聚类质心,解决了算法初始质心敏感的问题。在UCI数据集上进行的实验显示,MR-MSKCA较MR-KNMF、MR-PGDLSH、MR-GAPKCA的运行时间分别降低了45.1%、49.1%、59.8%,聚类效果分别提升了19.2%、22.8%、24%,表明MR-MSKCA对大数据进行聚类时有良好性能,适用于不同场景的大数据聚类分析。
基金supported by Russian Foundation for Basic Research grants No. 17-05-00989, No. 16-05-00753,NRU HSE and visiting grants positions at Paris observatory and Wuhan university for the first authorpartially supported by grants by NSF/IGFA Belmont Forum Project (Grant No. ICER-1342644)the Chinese Academy of Sciences/SAFEA International Partnership Program for Creative Research Teams(Grant No. KZZD-EW-TZ-05)
文摘Earth＇s variable rotation is mainly produced by the variability of the AAM（atmospheric angular momentum）. In particular, the axial AAM component X_3, which undergoes especially strong variations,induces changes in the Earth＇s rotation rate. In this study we analysed maps of regional input into the effective axial AAM from 1948 through 2011 from NCEP/NCAR reanalysis. Global zonal circulation patterns related to the LOD（length of day） were described. We applied MSSA（Multichannel Singular Spectrum Analysis） jointly to the mass and motion components of AAM, which allowed us to extract annual, semiannual, 4-mo nth, quasi-biennial, 5-year, and low-frequency oscillations. PCs（Principal components） strongly related to ENSO（El Nino southern oscillation） were released. They can be used to study ENSO-induced changes in pressure and wind fields and their coupling to LOD. The PCs describing the trends have captured slow atmospheric circulation changes possibly related to climate variability.
