目的建立基于同位素稀释液相色谱串联质谱技术(liquid phase chromatography tandem mass spectrometry,LC-MS/MS)的血清25羟维生素D3[25-hydroxy vitamin D3,25(OH)D3]的候选参考测量程序。方法采用同位素标准溶液为内标,液液萃取进行...目的建立基于同位素稀释液相色谱串联质谱技术(liquid phase chromatography tandem mass spectrometry,LC-MS/MS)的血清25羟维生素D3[25-hydroxy vitamin D3,25(OH)D3]的候选参考测量程序。方法采用同位素标准溶液为内标,液液萃取进行前处理,正离子电喷雾模式进行监测。参照美国临床实验室标准化协会(Clinical and Laboratory Standards Institute,CLSI)C62-A和EP15-A3等文件,对方法的正确度、精密度、线性范围、定量限、检测下限、相对基质效应等进行验证。采用候选参考测量程序和质谱常规程序检测40份临床血清样本,评价两种方法的一致性。结果候选方法的分析时间为15 min,通过色谱的等度洗脱可有效分离同分异构体3-epi-25(OH)D3,特异度好。测定参考实验室室间比对(RELA)样本,偏倚低于1.5%。批内精密度和批间精密度分别为0.75%~2.31%和1.28%~2.01%。定量限和检测下限分别为0.85 ng/ml和1.84 ng/ml。在2.5~220ng/ml浓度范围内线性良好。无相对基质效应和携带污染。质谱常规程序与候选参考程序的相关性较好(r=0.982),但低浓度样本处的偏差超出卫健委临检中心室间质评的允许总误差±25%。结论成功建立了基于LC-MS/MS技术的血清25(OH)D3的候选参考测量程序,分析性能符合要求,可用于临床常规方法的量值溯源。展开更多
With an extension of the geological entropy concept in porous media,the approach called directional entrogram is applied to link hydraulic behavior to the anisotropy of the 3D fracture networks.A metric called directi...With an extension of the geological entropy concept in porous media,the approach called directional entrogram is applied to link hydraulic behavior to the anisotropy of the 3D fracture networks.A metric called directional entropic scale is used to measure the anisotropy of spatial order in different directions.Compared with the traditional connectivity indexes based on the statistics of fracture geometry,the directional entropic scale is capable to quantify the anisotropy of connectivity and hydraulic conductivity in heterogeneous 3D fracture networks.According to the numerical analysis of directional entrogram and fluid flow in a number of the 3D fracture networks,the hydraulic conductivities and entropic scales in different directions both increase with spatial order(i.e.,trace length decreasing and spacing increasing)and are independent of the dip angle.As a result,the nonlinear correlation between the hydraulic conductivities and entropic scales from different directions can be unified as quadratic polynomial function,which can shed light on the anisotropic effect of spatial order and global entropy on the heterogeneous hydraulic behaviors.展开更多
针对经天路图软件不能对多层状地质体的地基承载力进行快速分析的问题,基于3D WinForms控件Eyeshot,利用C#语言在Visual Studio 2019平台上研发了经天路图与地基承载力分析软件FLAC^(3D)之间的接口程序。研发中采用了三角网算法、多层...针对经天路图软件不能对多层状地质体的地基承载力进行快速分析的问题,基于3D WinForms控件Eyeshot,利用C#语言在Visual Studio 2019平台上研发了经天路图与地基承载力分析软件FLAC^(3D)之间的接口程序。研发中采用了三角网算法、多层状地质体可视化算法和网格优化算法等。所研发的接口程序具有图形化显示界面,能够从经天路图读取多层状地质体地形数据,并根据地质勘探数据对地质体分层,能够在ANSYS中自动建立有限元网格模型,基于FLAC^(3D)命令流自动完成网格模型读入与转换、材料属性和边界条件的定义等前处理工作并执行求解,能够自动导出常用分析结果并回传至经天路图。算例验证表明,采用接口程序对多层状地质体进行地基承载力分析,极大地提升了设计人员的工作效率。展开更多
Direct air capture(DAC)of CO_(2)plays an indispensable role in achieving carbon-neutral goals as one of the key negative emission technologies.Since large air flows are required to capture the ultradilute CO_(2)from t...Direct air capture(DAC)of CO_(2)plays an indispensable role in achieving carbon-neutral goals as one of the key negative emission technologies.Since large air flows are required to capture the ultradilute CO_(2)from the air,lab-synthesized adsorbents in powder form may cause unacceptable gas pressure drops and poor heat and mass transfer efficiencies.A structured adsorbent is essential for the implementation of gas-solid contactors for cost-and energy-efficient DAC systems.In this study,efficient adsorbent poly(ethyleneimine)(PEI)-functionalized Mg-Al-CO_(3)layered double hydroxide(LDH)-derived mixed metal oxides(MMOs)are three-dimensional(3D)printed into monoliths for the first time with more than 90%adsorbent loadings.The printing process has been optimized by initially printing the LDH powder into monoliths followed by calcination into MMO monoliths.This structure exhibits a 32.7%higher specific surface area and a 46.1%higher pore volume,as compared to the direct printing of the MMO powder into a monolith.After impregnation of PEI,the monolith demonstrates a large adsorption capacity(1.82 mmol/g)and fast kinetics(0.7 mmol/g/h)using a CO_(2)feed gas at 400 ppm at 25℃,one of the highest values among the shaped DAC adsorbents.Smearing of the amino-polymers during the post-printing process affects the diffusion of CO_(2),resulting in slower adsorption kinetics of pre-impregnation monoliths compared to post-impregnation monoliths.The optimal PEI/MeOH ratio for the post-impregnation solution prevents pores clogging that would affect both adsorption capacity and kinetics.展开更多
Helical hierarchy found in biomolecules like cellulose,chitin,and collagen underpins the remarkable mechanical strength and vibrant colors observed in living organisms.This study advances the integration of helical/ch...Helical hierarchy found in biomolecules like cellulose,chitin,and collagen underpins the remarkable mechanical strength and vibrant colors observed in living organisms.This study advances the integration of helical/chiral assembly and 3D printing technology,providing precise spatial control over chiral nano/microstructures of rod-shaped colloidal nanoparticles in intricate geometries.We designed reactive chiral inks based on cellulose nanocrystal(CNC)suspensions and acrylamide monomers,enabling the chiral assembly at nano/microscale,beyond the resolution seen in printed materials.We employed a range of complementary techniques including Orthogonal Superposition rheometry and in situ rheo-optic measurements under steady shear rate conditions.These techniques help us to understand the nature of the nonlinear flow behavior of the chiral inks,and directly probe the flow-induced microstructural dynamics and phase transitions at constant shear rates,as well as their post-flow relaxation.Furthermore,we analyzed the photo-curing process to identify key parameters affecting gelation kinetics and structural integrity of the printed object within the supporting bath.These insights into the interplay between the chiral inks self-assembly dynamics,3D printing flow kinematics and photopolymerization kinetics provide a roadmap to direct the out-of-equilibrium arrangement of CNC particles in the 3D printed filaments,ranging from uniform nematic to 3D concentric chiral structures with controlled pitch length,as well as random orientation of chiral domains.Our biomimetic approach can pave the way for the creation of materials with superior mechanical properties or programable photonic responses that arise from 3D nano/microstructure and can be translated into larger scale 3D printed designs.展开更多
Three dimensional(3D)echocardiogram enables cardiologists to visua-lize suspicious cardiac structures in detail.In recent years,this three-dimensional echocardiogram carries important clinical value in virtual surgica...Three dimensional(3D)echocardiogram enables cardiologists to visua-lize suspicious cardiac structures in detail.In recent years,this three-dimensional echocardiogram carries important clinical value in virtual surgical simulation.However,this 3D echocardiogram involves a trade-off difficulty between accu-racy and efficient computation in clinical diagnosis.This paper presents a novel Flip Directional 3D Volume Reconstruction(FD-3DVR)method for the recon-struction of echocardiogram images.The proposed method consists of two main steps:multiplanar volumetric imaging and 3D volume reconstruction.In the crea-tion of multiplanar volumetric imaging,two-dimensional(2D)image pixels are mapped into voxels of the volumetric grid.As the obtained slices are discontin-uous,there are some missing voxels in the volume data.To restore the structural and textural information of 3D ultrasound volume,the proposed method creates a volume pyramid in parallel with theflip directional texture pyramid.Initially,the nearest neighbors of missing voxels in the multiplanar volumetric imaging are identified by 3D ANN(Approximate Nearest Neighbor)patch matching method.Furthermore,aflip directional texture pyramid is proposed and aggregated with distance in patch matching tofind out the most similar neighbors.In the recon-struction step,structural and textural information obtained from differentflip angle directions can reconstruct 3D volume well with the desired accuracy.Com-pared with existing 3D reconstruction methods,the proposed Flip Directional 3D Volume Reconstruction(FD-3DVR)method provides superior performance for the mean peak signal-to-noise ratio(40.538 for the proposed method I and 39.626 for the proposed method II).Experimental results performed on the cardi-ac datasets demonstrate the efficiency of the proposed method for the reconstruc-tion of echocardiogram images.展开更多
如何生成具有适当水平位差的左右眼平面图片是自由立体显示软件设计的核心问题。针对该问题,首先以双眼能够舒适地融合显示屏上的最大水平位差为依据,在M icrosoft D irect 3D构建的3维模型空间体系内,寻找模型空间的视点与显示屏上水...如何生成具有适当水平位差的左右眼平面图片是自由立体显示软件设计的核心问题。针对该问题,首先以双眼能够舒适地融合显示屏上的最大水平位差为依据,在M icrosoft D irect 3D构建的3维模型空间体系内,寻找模型空间的视点与显示屏上水平位差之间的理论关系;然后,以视者在真实空间浏览3维模型真实感强、视觉舒适为原则来确定模型空间视点位置和投射表面平移量;最后,还提出了调整立体视觉效果的参数,并阐述了它们对立体视觉效果的影响机制。该研究成果已经投入使用,并获得了理想的立体视觉效果。展开更多
文摘目的建立基于同位素稀释液相色谱串联质谱技术(liquid phase chromatography tandem mass spectrometry,LC-MS/MS)的血清25羟维生素D3[25-hydroxy vitamin D3,25(OH)D3]的候选参考测量程序。方法采用同位素标准溶液为内标,液液萃取进行前处理,正离子电喷雾模式进行监测。参照美国临床实验室标准化协会(Clinical and Laboratory Standards Institute,CLSI)C62-A和EP15-A3等文件,对方法的正确度、精密度、线性范围、定量限、检测下限、相对基质效应等进行验证。采用候选参考测量程序和质谱常规程序检测40份临床血清样本,评价两种方法的一致性。结果候选方法的分析时间为15 min,通过色谱的等度洗脱可有效分离同分异构体3-epi-25(OH)D3,特异度好。测定参考实验室室间比对(RELA)样本,偏倚低于1.5%。批内精密度和批间精密度分别为0.75%~2.31%和1.28%~2.01%。定量限和检测下限分别为0.85 ng/ml和1.84 ng/ml。在2.5~220ng/ml浓度范围内线性良好。无相对基质效应和携带污染。质谱常规程序与候选参考程序的相关性较好(r=0.982),但低浓度样本处的偏差超出卫健委临检中心室间质评的允许总误差±25%。结论成功建立了基于LC-MS/MS技术的血清25(OH)D3的候选参考测量程序,分析性能符合要求,可用于临床常规方法的量值溯源。
基金supported by the National Natural Science Foundation of China(Nos.42077243,52209148,and 52079062).
文摘With an extension of the geological entropy concept in porous media,the approach called directional entrogram is applied to link hydraulic behavior to the anisotropy of the 3D fracture networks.A metric called directional entropic scale is used to measure the anisotropy of spatial order in different directions.Compared with the traditional connectivity indexes based on the statistics of fracture geometry,the directional entropic scale is capable to quantify the anisotropy of connectivity and hydraulic conductivity in heterogeneous 3D fracture networks.According to the numerical analysis of directional entrogram and fluid flow in a number of the 3D fracture networks,the hydraulic conductivities and entropic scales in different directions both increase with spatial order(i.e.,trace length decreasing and spacing increasing)and are independent of the dip angle.As a result,the nonlinear correlation between the hydraulic conductivities and entropic scales from different directions can be unified as quadratic polynomial function,which can shed light on the anisotropic effect of spatial order and global entropy on the heterogeneous hydraulic behaviors.
文摘针对经天路图软件不能对多层状地质体的地基承载力进行快速分析的问题,基于3D WinForms控件Eyeshot,利用C#语言在Visual Studio 2019平台上研发了经天路图与地基承载力分析软件FLAC^(3D)之间的接口程序。研发中采用了三角网算法、多层状地质体可视化算法和网格优化算法等。所研发的接口程序具有图形化显示界面,能够从经天路图读取多层状地质体地形数据,并根据地质勘探数据对地质体分层,能够在ANSYS中自动建立有限元网格模型,基于FLAC^(3D)命令流自动完成网格模型读入与转换、材料属性和边界条件的定义等前处理工作并执行求解,能够自动导出常用分析结果并回传至经天路图。算例验证表明,采用接口程序对多层状地质体进行地基承载力分析,极大地提升了设计人员的工作效率。
基金supported by the Shanghai Agricultural Science and Technology Program (2022-02-08-00-12-F01176)he National Natural Science Foundation of China (52006135)
文摘Direct air capture(DAC)of CO_(2)plays an indispensable role in achieving carbon-neutral goals as one of the key negative emission technologies.Since large air flows are required to capture the ultradilute CO_(2)from the air,lab-synthesized adsorbents in powder form may cause unacceptable gas pressure drops and poor heat and mass transfer efficiencies.A structured adsorbent is essential for the implementation of gas-solid contactors for cost-and energy-efficient DAC systems.In this study,efficient adsorbent poly(ethyleneimine)(PEI)-functionalized Mg-Al-CO_(3)layered double hydroxide(LDH)-derived mixed metal oxides(MMOs)are three-dimensional(3D)printed into monoliths for the first time with more than 90%adsorbent loadings.The printing process has been optimized by initially printing the LDH powder into monoliths followed by calcination into MMO monoliths.This structure exhibits a 32.7%higher specific surface area and a 46.1%higher pore volume,as compared to the direct printing of the MMO powder into a monolith.After impregnation of PEI,the monolith demonstrates a large adsorption capacity(1.82 mmol/g)and fast kinetics(0.7 mmol/g/h)using a CO_(2)feed gas at 400 ppm at 25℃,one of the highest values among the shaped DAC adsorbents.Smearing of the amino-polymers during the post-printing process affects the diffusion of CO_(2),resulting in slower adsorption kinetics of pre-impregnation monoliths compared to post-impregnation monoliths.The optimal PEI/MeOH ratio for the post-impregnation solution prevents pores clogging that would affect both adsorption capacity and kinetics.
基金the support from the University of South Carolina
文摘Helical hierarchy found in biomolecules like cellulose,chitin,and collagen underpins the remarkable mechanical strength and vibrant colors observed in living organisms.This study advances the integration of helical/chiral assembly and 3D printing technology,providing precise spatial control over chiral nano/microstructures of rod-shaped colloidal nanoparticles in intricate geometries.We designed reactive chiral inks based on cellulose nanocrystal(CNC)suspensions and acrylamide monomers,enabling the chiral assembly at nano/microscale,beyond the resolution seen in printed materials.We employed a range of complementary techniques including Orthogonal Superposition rheometry and in situ rheo-optic measurements under steady shear rate conditions.These techniques help us to understand the nature of the nonlinear flow behavior of the chiral inks,and directly probe the flow-induced microstructural dynamics and phase transitions at constant shear rates,as well as their post-flow relaxation.Furthermore,we analyzed the photo-curing process to identify key parameters affecting gelation kinetics and structural integrity of the printed object within the supporting bath.These insights into the interplay between the chiral inks self-assembly dynamics,3D printing flow kinematics and photopolymerization kinetics provide a roadmap to direct the out-of-equilibrium arrangement of CNC particles in the 3D printed filaments,ranging from uniform nematic to 3D concentric chiral structures with controlled pitch length,as well as random orientation of chiral domains.Our biomimetic approach can pave the way for the creation of materials with superior mechanical properties or programable photonic responses that arise from 3D nano/microstructure and can be translated into larger scale 3D printed designs.
文摘Three dimensional(3D)echocardiogram enables cardiologists to visua-lize suspicious cardiac structures in detail.In recent years,this three-dimensional echocardiogram carries important clinical value in virtual surgical simulation.However,this 3D echocardiogram involves a trade-off difficulty between accu-racy and efficient computation in clinical diagnosis.This paper presents a novel Flip Directional 3D Volume Reconstruction(FD-3DVR)method for the recon-struction of echocardiogram images.The proposed method consists of two main steps:multiplanar volumetric imaging and 3D volume reconstruction.In the crea-tion of multiplanar volumetric imaging,two-dimensional(2D)image pixels are mapped into voxels of the volumetric grid.As the obtained slices are discontin-uous,there are some missing voxels in the volume data.To restore the structural and textural information of 3D ultrasound volume,the proposed method creates a volume pyramid in parallel with theflip directional texture pyramid.Initially,the nearest neighbors of missing voxels in the multiplanar volumetric imaging are identified by 3D ANN(Approximate Nearest Neighbor)patch matching method.Furthermore,aflip directional texture pyramid is proposed and aggregated with distance in patch matching tofind out the most similar neighbors.In the recon-struction step,structural and textural information obtained from differentflip angle directions can reconstruct 3D volume well with the desired accuracy.Com-pared with existing 3D reconstruction methods,the proposed Flip Directional 3D Volume Reconstruction(FD-3DVR)method provides superior performance for the mean peak signal-to-noise ratio(40.538 for the proposed method I and 39.626 for the proposed method II).Experimental results performed on the cardi-ac datasets demonstrate the efficiency of the proposed method for the reconstruc-tion of echocardiogram images.
文摘如何生成具有适当水平位差的左右眼平面图片是自由立体显示软件设计的核心问题。针对该问题,首先以双眼能够舒适地融合显示屏上的最大水平位差为依据,在M icrosoft D irect 3D构建的3维模型空间体系内,寻找模型空间的视点与显示屏上水平位差之间的理论关系;然后,以视者在真实空间浏览3维模型真实感强、视觉舒适为原则来确定模型空间视点位置和投射表面平移量;最后,还提出了调整立体视觉效果的参数,并阐述了它们对立体视觉效果的影响机制。该研究成果已经投入使用,并获得了理想的立体视觉效果。
