Image-based rock typing(IBRT)is an effective way to understand the pore scale heterogeneity of the reservoir samples.IBRT is aimed at segmenting a rock sample's image into different regions where each region repre...Image-based rock typing(IBRT)is an effective way to understand the pore scale heterogeneity of the reservoir samples.IBRT is aimed at segmenting a rock sample's image into different regions where each region represents a homogeneous porous medium,also known as rock type.Currently,the phase-field rock typing method has attracted more attention due to its impressive performance in classifying the heterogeneous rock images with highly irregular pore structures.In this paper,a modified specific surface CV(SSCV)model is proposed to realize the IBRT.In the SSCV model,the specific surface of a pixel is calculated within a given size neighborhood to distinguish different rock types,and the iterative convolution-thresholding method(ICTM)is applied as the classifier.Compared to the LHFCV method,an existing phase-field rock typing method,the proposed SSCV is capable of processing the images with more than two rock types and can be solved by ICTM which has higher computational efficiency.The proposed SSCV method has demonstrated remarkable performance in the segmentation of various images of both synthetic and natural rock samples.展开更多
A simple method was developed to prepare the uniform hematite hollow submicro-spheres with controllable structure and different diameter based on monodisperse poly（styrene-co-acrylic acid） [P（St-co-AA）] particles....A simple method was developed to prepare the uniform hematite hollow submicro-spheres with controllable structure and different diameter based on monodisperse poly（styrene-co-acrylic acid） [P（St-co-AA）] particles. The structure and formation mechanism of the hollow spheres were investigated in detail. The control mechanism of shell thickness was also discussed. The results indicated that the shell thickness and coarseness of the synthesized core-shell hematite hollow spheres could be tuned simply by the surface carboxyl content of the P（St-co-AA） particles. This method provided a new approach for the structure control in the preparation of hollow spheres. A Brunauer-Emmett-Teller （BET） test shows that the prepared hollow spheres have large surface areas which were decreased along with the increase of the diameter. The magnetic properties of the as-obtained hematite hollow spheres were investigated. The result showed that the coercivity and saturated magnetization were increased along with the increase of the shell thickness, and the remanent magnetization was increased along with the decrease of the diameter.展开更多
Helium ion scanning microscopy(HIM)is a novel high-resolution scanning microscopy technique that uses helium ions instead of electrons to form images of the highest quality and resolution,providing a sub-nanometer res...Helium ion scanning microscopy(HIM)is a novel high-resolution scanning microscopy technique that uses helium ions instead of electrons to form images of the highest quality and resolution,providing a sub-nanometer resolution sputter uncoated biological cell.Here,we took advantage of HIM to explore the cell surface of Tritrichomonas foetus,a protist parasite of cattle that provokes hard infection and abortion in cows.We describe thin protrusions,like nanotubes described in other cells,with different sizes(27 nm to 81 nm in thickness)and various lengths(from 73 nm to 2μm),as well bulbous structures either budding from the cell surface or present in the extremities of some protrusions.The flagella also presented these thin protrusions and different protein decoration,similar to those previously described using freeze-fracture techniques.Nanotubes between two cells were also seen,and their role in infection is discussed.The cell surface was also examined and showed several pits indicative of endocytic activity and other types of arrays of particles.These observations were confirmed using Scanning Electron Microscopy(SEM),negative staining,and conventional thin sectioning for observation by transmission electron microscopy.Our findings provide new and relevant information that may contribute to a better understanding of protozoan biology and its interaction with mammalian cells.展开更多
基金supported by the Hong Kong Polytechnic University(Grant Nos.G-UAEY,4-ZZLS)the CAS AMSS-PolyU Joint Laboratory of Applied Mathematics(Grant No.1-ZVA8)+1 种基金the King Abdullah University of Science and Technology(Grant Nos.BAS/1/1351-01,URF/1/4074-01,URF/1/3769-01)the Maths4DL program(Grant No.EP/V026259/1).
文摘Image-based rock typing(IBRT)is an effective way to understand the pore scale heterogeneity of the reservoir samples.IBRT is aimed at segmenting a rock sample's image into different regions where each region represents a homogeneous porous medium,also known as rock type.Currently,the phase-field rock typing method has attracted more attention due to its impressive performance in classifying the heterogeneous rock images with highly irregular pore structures.In this paper,a modified specific surface CV(SSCV)model is proposed to realize the IBRT.In the SSCV model,the specific surface of a pixel is calculated within a given size neighborhood to distinguish different rock types,and the iterative convolution-thresholding method(ICTM)is applied as the classifier.Compared to the LHFCV method,an existing phase-field rock typing method,the proposed SSCV is capable of processing the images with more than two rock types and can be solved by ICTM which has higher computational efficiency.The proposed SSCV method has demonstrated remarkable performance in the segmentation of various images of both synthetic and natural rock samples.
基金Funded by the New Century Excellent Talent Plan from Ministry of Education,China (No.NCET-05-0660)Fok YingTung Education Foundation (No. 101049)
文摘A simple method was developed to prepare the uniform hematite hollow submicro-spheres with controllable structure and different diameter based on monodisperse poly（styrene-co-acrylic acid） [P（St-co-AA）] particles. The structure and formation mechanism of the hollow spheres were investigated in detail. The control mechanism of shell thickness was also discussed. The results indicated that the shell thickness and coarseness of the synthesized core-shell hematite hollow spheres could be tuned simply by the surface carboxyl content of the P（St-co-AA） particles. This method provided a new approach for the structure control in the preparation of hollow spheres. A Brunauer-Emmett-Teller （BET） test shows that the prepared hollow spheres have large surface areas which were decreased along with the increase of the diameter. The magnetic properties of the as-obtained hematite hollow spheres were investigated. The result showed that the coercivity and saturated magnetization were increased along with the increase of the shell thickness, and the remanent magnetization was increased along with the decrease of the diameter.
基金This work was supported by the Conselho Nacional de Desenvolvimento Cientifico e Tecnologico(CNPq),Programa de Excelência a Pesquisa/Instituto Aggeu Magalhães(CNPq/PROEP-IAM grant:400740/2019-2),Financiadora de Estudos e Projetos(FINEP),and Fundação Carlos Chagas Filho de AmparoàPesquisa no Estado do Rio de Janeiro(FAPERJ).
文摘Helium ion scanning microscopy(HIM)is a novel high-resolution scanning microscopy technique that uses helium ions instead of electrons to form images of the highest quality and resolution,providing a sub-nanometer resolution sputter uncoated biological cell.Here,we took advantage of HIM to explore the cell surface of Tritrichomonas foetus,a protist parasite of cattle that provokes hard infection and abortion in cows.We describe thin protrusions,like nanotubes described in other cells,with different sizes(27 nm to 81 nm in thickness)and various lengths(from 73 nm to 2μm),as well bulbous structures either budding from the cell surface or present in the extremities of some protrusions.The flagella also presented these thin protrusions and different protein decoration,similar to those previously described using freeze-fracture techniques.Nanotubes between two cells were also seen,and their role in infection is discussed.The cell surface was also examined and showed several pits indicative of endocytic activity and other types of arrays of particles.These observations were confirmed using Scanning Electron Microscopy(SEM),negative staining,and conventional thin sectioning for observation by transmission electron microscopy.Our findings provide new and relevant information that may contribute to a better understanding of protozoan biology and its interaction with mammalian cells.
