Objective： To evaluate the role of spiral CT imaging postprocessing techniques in preoperative TNM staging of lung cancer. Methods： 106 patients with pathologically confirmed lung cancer received spiral CT examinati...Objective： To evaluate the role of spiral CT imaging postprocessing techniques in preoperative TNM staging of lung cancer. Methods： 106 patients with pathologically confirmed lung cancer received spiral CT examinations with a new revised TNM staging method of lung cancer which was taken as criterion of diagnosis. The images were reconstructed by using different postprocessing techniques such as MPR, MIP, SSD, VR, and their TNM staging capabilities were assessed by using postprocessing imaging and the results with axial CT images were compared. Results： In T staging, the accurate rates of axial CT images in T1-T4 staging were 77.3%, 60.6%, 60.7%, and 60.3% respectively; for postprocessing images, the accurate rates were 86.4%, 90.9%, 89.3%, and 87.0% respectively, In N staging, the accurate rates of axial CT images were 84.6%, 68.1%, 63.6%, and 64.2% in N0-N3 staging, respectively; but they were 92.3%, 90.9%, 90.9%, and 85.7% in postprocessing images, respectively. The postprocessing images were superior to axial CT images in T1-T3 and N1-N3 staging of lung cancer but there were no significant differences in T1 and NO staging. For metastasis, the postprocessing images may be helpful for the TNM staging of lung cancer. Conclusion： The postprocessing techniques of the spiral CT could improve the accurate rates of TNM staging of lung cancer, and represent a useful complement to the axial CT.展开更多
Because of restriction of workspace of parallel kinematics Machine (PKM), 6 DOF PKM can’t finish machining of workpiece with complicated surfaces under only once locating. It is necessary to fit workpiece beyond twic...Because of restriction of workspace of parallel kinematics Machine (PKM), 6 DOF PKM can’t finish machining of workpiece with complicated surfaces under only once locating. It is necessary to fit workpiece beyond twice and to lead to low machining precision. Therefore the seven-axis linkage PKM is implemented by fixing a turntable on the worktable of the six-axis linkage PKM. However, the turntable angle decomposing problem from the CL file should be well considered. If the traditional decomposing methods are adopted, the nutation angle usually goes beyond the workspace of the machine. Therefore, according to the relation of the machine coordinate system and the workpiece coordinate system, the turntable angle decomposition algorithmic of the consistent coordinate system and the turntable angle decomposition algorithmic of the non-consistent coordinate system are developed to resolve the problem mentioned above. The turntable angle decomposition of the non-consistent coordinate system processes the decomposition which is based on the consistent coordinate system again. It calculates the initial angle of the locating workpiece, and the decomposed angle of the turntable at the machine coordinate system results in the nutation angle not going beyond workspace of the machine, thereby the decomposition process can be simplified.展开更多
The combination of deep wet etching and a magneto-rheological finishing （MRF） process is investigated to simultaneously improve laser damage resistance of a fused-silica surface at 355 nm. The subsequently deposited...The combination of deep wet etching and a magneto-rheological finishing （MRF） process is investigated to simultaneously improve laser damage resistance of a fused-silica surface at 355 nm. The subsequently deposited SiO2 coatings are researched to clarify the impact of substrate finishing technology on the coatings. It is revealed that a deep removal proceeding from the single side or double side had a significant impact on the laser-induced damage threshold （LIDT） of the fused silica, especially for the rear surface. After the deep etching, the MRF process that followed does not actually increase the LIDT, but it does ameliorate the surface qualities without additional LIDT degradation. The combination guarantee both the integrity of the surface＇s finish and the laser damage resistance of the fused silica and subsequent SiO2 coatings.展开更多
It is demonstrated that spectral methods can be used to improve the accuracy of numerical solutions obtained by some lower order methods.More precisely,we can use spectral methods to postprocess numerical solutions of...It is demonstrated that spectral methods can be used to improve the accuracy of numerical solutions obtained by some lower order methods.More precisely,we can use spectral methods to postprocess numerical solutions of initial value differential equations.After a few number of iterations(say 3 to 4),the errors can decrease to a few orders of magnitude less.The iteration uses the Gauss-Seidel type strategy,which gives an explicit way of postprocessing.Numerical examples for ODEs,Hamiltonian system and integral equations are provided.They all indicate that the spectral processing technique can be a very useful way in improving the accuracy of the numerical solutions.In particular,for a Hamiltonian system accuracy is only one of the issues;some other conservative properties are even more important for large time simulations.The spectral postprocessing with the coarse-mesh symplectic initial guess can not only produce high accurate approximations but can also save a significant amount of computational time over the standard symplectic schemes.展开更多
The post-processing procedure is given by a interpolant postprocessing of the finit element solution by appropriately-define finite dimensional subspaces, The corresponding superconvergence are established on general ...The post-processing procedure is given by a interpolant postprocessing of the finit element solution by appropriately-define finite dimensional subspaces, The corresponding superconvergence are established on general quasi-regular finite element partitions.展开更多
Objective： To explore whether single and fused monochromatic images can improve liver tumor detection and delineation by single source dual energy CT （ssDECT） in patients with hepatocellular carcinoma （HCC） durin...Objective： To explore whether single and fused monochromatic images can improve liver tumor detection and delineation by single source dual energy CT （ssDECT） in patients with hepatocellular carcinoma （HCC） during arterial phase. Methods： Fifty-seven patients with HCC who underwent ssDECT scanning at Beijing Cancer Hospital were enrolled retrospectively. Twenty-one sets of monochromatic images from 40 to 140 keV were reconstructed at 5 keV intervals in arterial phase. The optimal contrast-noise ratio （CNR） monochromatic images of the liver tumor and the lowest-noise monochromatic images were selected for image fusion. We evaluated the image quality of the optimal-CNR monochromatic images, the lowest-noise monochromatic images and the fused monochromatic images, respectively. The evaluation indicators included the spatial resolution of the anatomical structure, the noise level, the contrast and CNR of the tumor. Results： In arterial phase, the anatomical structure of the liver can be displayed most clearly in the 65-keV monochromatic images, with the lowest image noise. The optimal-CNR monochromatic images of HCC tumor were 50-keV monochromatic images in which the internal structural features of the liver tumors were displayed most clearly and meticulously. For tumor detection, the fused monochromatic images and the 50-keV monochromatic images had similar performances, and were more sensitive than 65-keV monochromatic images. Conclusions： We achieved good arterial phase images by fusing the optimal-CNR monochromatic images of the HCC tumor and the lowest-noise monochromatic images. The fused images displayed liver tumors and anatomical structures more clearly, which is potentially helpful for identifying more and smaller HCC tumors.展开更多
The convergence analysis of the lower order nonconforming element pro- posed by Park and Sheen is applied to the second-order elliptic problem under anisotropic meshes. The corresponding error estimation is obtained. ...The convergence analysis of the lower order nonconforming element pro- posed by Park and Sheen is applied to the second-order elliptic problem under anisotropic meshes. The corresponding error estimation is obtained. Moreover, by using the interpo- lation postprocessing technique, a global superconvergence property for the discretization error of the postprocessed discrete solution to the solution itself is derived. Numerical results are also given to verify the theoretical analysis.展开更多
This paper discusses the semidiscrete finite element method for nonlinear hyperbolic equations with nonlinear boundary condition. The superclose property is derived through interpolation instead of the nonlinear H^1 p...This paper discusses the semidiscrete finite element method for nonlinear hyperbolic equations with nonlinear boundary condition. The superclose property is derived through interpolation instead of the nonlinear H^1 projection and integral identity technique. Meanwhile, the global superconvergence is obtained based on the interpolated postprocessing techniques.展开更多
In this paper, a new higher order Wilson element is presented, and the convergence is proved. Then the interpolation postprocessing technique is used to obtain the global superconvergence and posterior error estimate ...In this paper, a new higher order Wilson element is presented, and the convergence is proved. Then the interpolation postprocessing technique is used to obtain the global superconvergence and posterior error estimate of higher accuracy of this new element for the Sobolev type equations.展开更多
In this paper, we focused on numerical solutions of carcinogenesis mutations models that are based on reaction-diffusion systems and Lotka-Volterra food chains. We consider the case with one and two-stages of mutation...In this paper, we focused on numerical solutions of carcinogenesis mutations models that are based on reaction-diffusion systems and Lotka-Volterra food chains. We consider the case with one and two-stages of mutations with appropriate initial conditions and the zero-flux boundary conditions. The main purpose is to construct a stable discretization scheme, which allows much accuracy than those of a standard approach. To this end, we use the spectral method to postprocess numerical solutions for the proposed model by using some classical methods for solving differential equations. The implementation of the algorithm is simple and it does not need to solve the linear or nonlinear system (in case the model is nonlinear). We simulate the one and two-stage carcinogenesis mutations model and compared the results with previously published ones.展开更多
There are amounts of issues to be resolved in the process of designing the fiber placement trajectory of the cylindrical component,such as the interference between the machine and the component and the over-travel of ...There are amounts of issues to be resolved in the process of designing the fiber placement trajectory of the cylindrical component,such as the interference between the machine and the component and the over-travel of the axis of rotation on the fiber placement head.When the pressure on the cylinder surface inclines in a certain direction or at an angle within the normal plane,the motion characteristics of the rotation axis will be different.This paper analyzes the pressure angle effect of the concave cylinder surface on the motion features of a fiber placement machine.The placement area is enlarged by tilting pressure with the same lifting stroke,which is significant in preventing interference and selecting post-processing algorithm.展开更多
Antibiotic abuse now poses a grave threat to global ecology and bestirs public concerns about the residue issue in daily necessities.The traceability measurements along supply chain or logistic circulation have become...Antibiotic abuse now poses a grave threat to global ecology and bestirs public concerns about the residue issue in daily necessities.The traceability measurements along supply chain or logistic circulation have become increasingly essential given the labile nature of diverse synthetic residuals on site.In an attempt to answer this urgency,here a miniaturized fluorometric aptasensor prototype was contrived that catered to the point-of-care screening norm for two typical additives:chloramphenicol and enrofloxacin.The key target-indicating module worked in vitro based on the competitive binding-induced fluorescence recovery of fluorescein-labeled aptamers,which were photobleached beforehand in the format of double helix on burlike nanogold carriers.The“prickly”geometry of the latter not just enriched the capture probes at preferentially substrate-accessible spires;but also contributed to a tip-enhanced surface plasmon effect,sensitizing the signal-on during the duplex dissociation even at nanomolar threshold of the analytes.On the other hand,to encompass a full portable,a set of optical devices were mounted within a 3D-printed cartridge(adaptor)to converge the light beam and route it towards the detector,for which the smartphone camera came up in handy with a home-developed App for calibrating the emissive brightness.Enlightened by the high-dynamic-range compression,an imaging diagnostic algorithm was built in to grid and digitize each slide in the album for augmented detection performance.Thus,a novel bio-to-silico integration was invented that capable of in situ rapid reporting on the antibiotic presence with high sensitivity and selectivity.Further field practices in spiked milk on sales proved the precision and rudimentary feasibility of the well-assembled model of appliance,thus holding nice prospects in nonexpert(e.g.,family and local community)utilities for foodborne antibiotic identification.展开更多
We introduce some ways to compute the lower and upper bounds of the Laplace eigenvalue problem.By using the special nonconforming finite elements,i.e.,enriched Crouzeix-Raviart element and extended Q1ro t,we get the l...We introduce some ways to compute the lower and upper bounds of the Laplace eigenvalue problem.By using the special nonconforming finite elements,i.e.,enriched Crouzeix-Raviart element and extended Q1ro t,we get the lower bound of the eigenvalue.Additionally,we use conforming finite elements to do the postprocessing to get the upper bound of the eigenvalue,which only needs to solve the corresponding source problems and a small eigenvalue problem if higher order postprocessing method is implemented.Thus,we can obtain the lower and upper bounds of the eigenvalues simultaneously by solving eigenvalue problem only once.Some numerical results are also presented to demonstrate our theoretical analysis.展开更多
Superconvergence of the mixed finite element methods for 2-d Maxwell equations is studied in this paper. Two order of superconvergent factor can be obtained for the k-th Nedelec elements on the rectangular meshes.
In this paper,we investigate the superconvergence property and the L∞-error estimates of mixed finite element methods for a semilinear elliptic control problem with an integral constraint.The state and co-state are a...In this paper,we investigate the superconvergence property and the L∞-error estimates of mixed finite element methods for a semilinear elliptic control problem with an integral constraint.The state and co-state are approximated by the order one Raviart-Thomas mixed finite element space and the control variable is approximated by piecewise constant functions or piecewise linear functions.We derive some superconvergence results for the control variable and the state variables when the control is approximated by piecewise constant functions.Moreover,we derive L∞-error estimates for both the control variable and the state variables when the control is discretized by piecewise linear functions.Finally,some numerical examples are given to demonstrate the theoretical results.展开更多
In this paper,we investigate the superconvergence property of the numerical solution to a quadratic elliptic control problem by using mixed finite element methods.The state and co-state are approximated by the order k...In this paper,we investigate the superconvergence property of the numerical solution to a quadratic elliptic control problem by using mixed finite element methods.The state and co-state are approximated by the order k=1 Raviart-Thomas mixed finite element spaces and the control variable is approximated by piecewise constant functions.We prove the superconvergence error estimate of h3/2 in L2-norm between the approximated solution and the average L2 projection of the control.Moreover,by the postprocessing technique,a quadratic superconvergence result of the control is derived.展开更多
A two-level discretization method for eigenvalue problems is studied.Compared to the standard Galerkin finite element discretization technique performed on a fine gridthis method discretizes the eigenvalue problem on ...A two-level discretization method for eigenvalue problems is studied.Compared to the standard Galerkin finite element discretization technique performed on a fine gridthis method discretizes the eigenvalue problem on a coarse grid and obtains an improved eigenvector(eigenvalue) approximation by solving only a linear problem on the fine grid (or two linear problemsfor the case of eigenvalue approximation of nonsymmetric problems). The improved solution has theasymptotic accuracy of the Galerkin discretization solution. The link between the method and theiterated Galerkin method is established. Error estimates for the general nonsymmetric case arederived.展开更多
In this study,the effect of different sampling rates(i.e.observation recording interval)on the Precise Point Positioning(PPP)solutions in terms of accuracy was investigated.For this purpose,a field test was carried ou...In this study,the effect of different sampling rates(i.e.observation recording interval)on the Precise Point Positioning(PPP)solutions in terms of accuracy was investigated.For this purpose,a field test was carried out inÇorum province,Turkey,on 11 September 2019.Within this context,a Geodetic Point(GP)was established and precisely coordinated.A static GNSS measurement was occupied on the GP for about 4-hour time at 0.10 second(s)/10 Hz measurement intervals with the Trimble R10 geodetic grade GNSS receiver.The original observation file was converted to RINEX format and then decimated into the different data sampling rates as 0.2 s,0.5 s,1 s,5 s,10 s,30 s,60 s,and 120 s.All these RINEX observation files were submitted to the Canadian Spatial Reference System-Precise Point Positioning(CSRS-PPP)online processing service the day after the data collection date by choosing both static and kinematic processing options.In this way,PPP-derived static coordinates,and the kinematic coordinates of each measurement epoch were calculated.The PPP-derived coordinates obtained from each decimated sampling intervals were compared to known coordinates of the GP for northing,easting,2D position,and height components.According to the static and kinematic processing results,high data sampling rates did not change the PPP solutions in terms of accuracy when compared to the results obtained using lower sampling rates.The results of this study imply that it was not necessary to collect GNSS data with high-rate intervals for many surveying projects requiring cm-level accuracy.展开更多
Discontinuous deformation analysis(DDA)has been widely applied for the simulation of block systems that have many discontinuous surfaces.The penalty method is utilized to ensure that there are no penetrations between ...Discontinuous deformation analysis(DDA)has been widely applied for the simulation of block systems that have many discontinuous surfaces.The penalty method is utilized to ensure that there are no penetrations between blocks.A linear polynomial function for displacement leads to a constant stress for a block,which cannot precisely describe the stress field within the block.Therefore,a high-order polynomial displacement function and a flue mesh are always used to improve the precision of the stress field.However,these means are not practical for simulating block systems that have many contacts.In this paper,the contact-stress-based stress recovery methods are proposed for DDA.High-precision solutions for the contact stresses on the boundaries of the blocks are utilized.The first-order Gaussian point of a block is the block's centroid,where the constant stress obtained via DDA is of higher precision.The high-precision solutions for the stresses are utilized in the least squares method to recover a single block's inner stress field.The proposed methods enhance the resolution of the stress field inside a single block without increasing the computational effort in the main iterative process for displacement in DDA.Numerical examples are simulated using both the finite element method(FEM)with a fine mesh and the proposed DDA program.The recovered DDA results can accurately describe the distribution of the stresses in a single block and,in some areas,have the same precision as the FEM results.Moreover,the precision of the proposed methods improves as the gradient of the contact stress on the boundary decreases.展开更多
Abstract. In this paper which is motivated by computation on parallel machine, we showthat the superconvergence results of the finite element method(FEM) with Lagrange mul-tipliers based on domain decomposition method...Abstract. In this paper which is motivated by computation on parallel machine, we showthat the superconvergence results of the finite element method(FEM) with Lagrange mul-tipliers based on domain decomposition method (DDM) with nonmatching grids can becarried over to parabolic problems. The main idea of this paper is to achieve the combina-tion of parallel computational method with the higher accuracy technique by interpolationfinite element postprocessing.展开更多
文摘Objective： To evaluate the role of spiral CT imaging postprocessing techniques in preoperative TNM staging of lung cancer. Methods： 106 patients with pathologically confirmed lung cancer received spiral CT examinations with a new revised TNM staging method of lung cancer which was taken as criterion of diagnosis. The images were reconstructed by using different postprocessing techniques such as MPR, MIP, SSD, VR, and their TNM staging capabilities were assessed by using postprocessing imaging and the results with axial CT images were compared. Results： In T staging, the accurate rates of axial CT images in T1-T4 staging were 77.3%, 60.6%, 60.7%, and 60.3% respectively; for postprocessing images, the accurate rates were 86.4%, 90.9%, 89.3%, and 87.0% respectively, In N staging, the accurate rates of axial CT images were 84.6%, 68.1%, 63.6%, and 64.2% in N0-N3 staging, respectively; but they were 92.3%, 90.9%, 90.9%, and 85.7% in postprocessing images, respectively. The postprocessing images were superior to axial CT images in T1-T3 and N1-N3 staging of lung cancer but there were no significant differences in T1 and NO staging. For metastasis, the postprocessing images may be helpful for the TNM staging of lung cancer. Conclusion： The postprocessing techniques of the spiral CT could improve the accurate rates of TNM staging of lung cancer, and represent a useful complement to the axial CT.
文摘Because of restriction of workspace of parallel kinematics Machine (PKM), 6 DOF PKM can’t finish machining of workpiece with complicated surfaces under only once locating. It is necessary to fit workpiece beyond twice and to lead to low machining precision. Therefore the seven-axis linkage PKM is implemented by fixing a turntable on the worktable of the six-axis linkage PKM. However, the turntable angle decomposing problem from the CL file should be well considered. If the traditional decomposing methods are adopted, the nutation angle usually goes beyond the workspace of the machine. Therefore, according to the relation of the machine coordinate system and the workpiece coordinate system, the turntable angle decomposition algorithmic of the consistent coordinate system and the turntable angle decomposition algorithmic of the non-consistent coordinate system are developed to resolve the problem mentioned above. The turntable angle decomposition of the non-consistent coordinate system processes the decomposition which is based on the consistent coordinate system again. It calculates the initial angle of the locating workpiece, and the decomposed angle of the turntable at the machine coordinate system results in the nutation angle not going beyond workspace of the machine, thereby the decomposition process can be simplified.
基金supported by the National Natural Science Foundation of China under Grant Nos.11104293 and 61308021
文摘The combination of deep wet etching and a magneto-rheological finishing （MRF） process is investigated to simultaneously improve laser damage resistance of a fused-silica surface at 355 nm. The subsequently deposited SiO2 coatings are researched to clarify the impact of substrate finishing technology on the coatings. It is revealed that a deep removal proceeding from the single side or double side had a significant impact on the laser-induced damage threshold （LIDT） of the fused silica, especially for the rear surface. After the deep etching, the MRF process that followed does not actually increase the LIDT, but it does ameliorate the surface qualities without additional LIDT degradation. The combination guarantee both the integrity of the surface＇s finish and the laser damage resistance of the fused silica and subsequent SiO2 coatings.
基金The research of the first author was supported by Hong Kong Baptist University,the Research Grants Council of Hong Kong.
文摘It is demonstrated that spectral methods can be used to improve the accuracy of numerical solutions obtained by some lower order methods.More precisely,we can use spectral methods to postprocess numerical solutions of initial value differential equations.After a few number of iterations(say 3 to 4),the errors can decrease to a few orders of magnitude less.The iteration uses the Gauss-Seidel type strategy,which gives an explicit way of postprocessing.Numerical examples for ODEs,Hamiltonian system and integral equations are provided.They all indicate that the spectral processing technique can be a very useful way in improving the accuracy of the numerical solutions.In particular,for a Hamiltonian system accuracy is only one of the issues;some other conservative properties are even more important for large time simulations.The spectral postprocessing with the coarse-mesh symplectic initial guess can not only produce high accurate approximations but can also save a significant amount of computational time over the standard symplectic schemes.
基金the Foundation of Natonal Natural Science of China and the Foundation of Aducation of Hunan Province.
文摘The post-processing procedure is given by a interpolant postprocessing of the finit element solution by appropriately-define finite dimensional subspaces, The corresponding superconvergence are established on general quasi-regular finite element partitions.
基金supported by the National Basic Research Program of China (973 Program) (Grant No. 2011CB707705)National Natural Science Foundation of China (Grant No. 81371715+1 种基金 81201215)the Capital Characteristic Clinical Application Research (Grant No. Z121107001012115)
文摘Objective： To explore whether single and fused monochromatic images can improve liver tumor detection and delineation by single source dual energy CT （ssDECT） in patients with hepatocellular carcinoma （HCC） during arterial phase. Methods： Fifty-seven patients with HCC who underwent ssDECT scanning at Beijing Cancer Hospital were enrolled retrospectively. Twenty-one sets of monochromatic images from 40 to 140 keV were reconstructed at 5 keV intervals in arterial phase. The optimal contrast-noise ratio （CNR） monochromatic images of the liver tumor and the lowest-noise monochromatic images were selected for image fusion. We evaluated the image quality of the optimal-CNR monochromatic images, the lowest-noise monochromatic images and the fused monochromatic images, respectively. The evaluation indicators included the spatial resolution of the anatomical structure, the noise level, the contrast and CNR of the tumor. Results： In arterial phase, the anatomical structure of the liver can be displayed most clearly in the 65-keV monochromatic images, with the lowest image noise. The optimal-CNR monochromatic images of HCC tumor were 50-keV monochromatic images in which the internal structural features of the liver tumors were displayed most clearly and meticulously. For tumor detection, the fused monochromatic images and the 50-keV monochromatic images had similar performances, and were more sensitive than 65-keV monochromatic images. Conclusions： We achieved good arterial phase images by fusing the optimal-CNR monochromatic images of the HCC tumor and the lowest-noise monochromatic images. The fused images displayed liver tumors and anatomical structures more clearly, which is potentially helpful for identifying more and smaller HCC tumors.
基金Project supported by the National Natural Science Foundation of China(Nos.10371113,10471133 and 10590353)
文摘The convergence analysis of the lower order nonconforming element pro- posed by Park and Sheen is applied to the second-order elliptic problem under anisotropic meshes. The corresponding error estimation is obtained. Moreover, by using the interpo- lation postprocessing technique, a global superconvergence property for the discretization error of the postprocessed discrete solution to the solution itself is derived. Numerical results are also given to verify the theoretical analysis.
基金Supported by the National Natural Science Foundation of China (10671184)
文摘This paper discusses the semidiscrete finite element method for nonlinear hyperbolic equations with nonlinear boundary condition. The superclose property is derived through interpolation instead of the nonlinear H^1 projection and integral identity technique. Meanwhile, the global superconvergence is obtained based on the interpolated postprocessing techniques.
基金the National Natural Science Foundation of China(10671184)
文摘In this paper, a new higher order Wilson element is presented, and the convergence is proved. Then the interpolation postprocessing technique is used to obtain the global superconvergence and posterior error estimate of higher accuracy of this new element for the Sobolev type equations.
文摘In this paper, we focused on numerical solutions of carcinogenesis mutations models that are based on reaction-diffusion systems and Lotka-Volterra food chains. We consider the case with one and two-stages of mutations with appropriate initial conditions and the zero-flux boundary conditions. The main purpose is to construct a stable discretization scheme, which allows much accuracy than those of a standard approach. To this end, we use the spectral method to postprocess numerical solutions for the proposed model by using some classical methods for solving differential equations. The implementation of the algorithm is simple and it does not need to solve the linear or nonlinear system (in case the model is nonlinear). We simulate the one and two-stage carcinogenesis mutations model and compared the results with previously published ones.
基金supported by the Equipment Development Department Project of China(No. 41422010401)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘There are amounts of issues to be resolved in the process of designing the fiber placement trajectory of the cylindrical component,such as the interference between the machine and the component and the over-travel of the axis of rotation on the fiber placement head.When the pressure on the cylinder surface inclines in a certain direction or at an angle within the normal plane,the motion characteristics of the rotation axis will be different.This paper analyzes the pressure angle effect of the concave cylinder surface on the motion features of a fiber placement machine.The placement area is enlarged by tilting pressure with the same lifting stroke,which is significant in preventing interference and selecting post-processing algorithm.
基金supported by National Natural Science Foundation of China(Nos.21874071 and 22204077)China Postdoctoral Science Foundation(No.2021M701722)Fundamental Research Funds for the Central Universities(Nos.30921013112 and 30922010501)。
文摘Antibiotic abuse now poses a grave threat to global ecology and bestirs public concerns about the residue issue in daily necessities.The traceability measurements along supply chain or logistic circulation have become increasingly essential given the labile nature of diverse synthetic residuals on site.In an attempt to answer this urgency,here a miniaturized fluorometric aptasensor prototype was contrived that catered to the point-of-care screening norm for two typical additives:chloramphenicol and enrofloxacin.The key target-indicating module worked in vitro based on the competitive binding-induced fluorescence recovery of fluorescein-labeled aptamers,which were photobleached beforehand in the format of double helix on burlike nanogold carriers.The“prickly”geometry of the latter not just enriched the capture probes at preferentially substrate-accessible spires;but also contributed to a tip-enhanced surface plasmon effect,sensitizing the signal-on during the duplex dissociation even at nanomolar threshold of the analytes.On the other hand,to encompass a full portable,a set of optical devices were mounted within a 3D-printed cartridge(adaptor)to converge the light beam and route it towards the detector,for which the smartphone camera came up in handy with a home-developed App for calibrating the emissive brightness.Enlightened by the high-dynamic-range compression,an imaging diagnostic algorithm was built in to grid and digitize each slide in the album for augmented detection performance.Thus,a novel bio-to-silico integration was invented that capable of in situ rapid reporting on the antibiotic presence with high sensitivity and selectivity.Further field practices in spiked milk on sales proved the precision and rudimentary feasibility of the well-assembled model of appliance,thus holding nice prospects in nonexpert(e.g.,family and local community)utilities for foodborne antibiotic identification.
基金supported by National Science Foundations of China (Grant Nos. 11001259,11031006)Croucher Foundation of Hong Kong Baptist University
文摘We introduce some ways to compute the lower and upper bounds of the Laplace eigenvalue problem.By using the special nonconforming finite elements,i.e.,enriched Crouzeix-Raviart element and extended Q1ro t,we get the lower bound of the eigenvalue.Additionally,we use conforming finite elements to do the postprocessing to get the upper bound of the eigenvalue,which only needs to solve the corresponding source problems and a small eigenvalue problem if higher order postprocessing method is implemented.Thus,we can obtain the lower and upper bounds of the eigenvalues simultaneously by solving eigenvalue problem only once.Some numerical results are also presented to demonstrate our theoretical analysis.
基金This work is subsidized by the special funds for major state basic research projects (No. 1999032800).
文摘Superconvergence of the mixed finite element methods for 2-d Maxwell equations is studied in this paper. Two order of superconvergent factor can be obtained for the k-th Nedelec elements on the rectangular meshes.
基金supported by Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme(2008)National Science Foundation of China(10971074)+1 种基金Specialized Research Fund for the Doctoral Program of Higher Education(20114407110009)the Foundation for High-level Talent Faculty of Guangdong Provincial University,and Hunan Provincial Innovation Foundation for Postgraduate CX2010B247.
文摘In this paper,we investigate the superconvergence property and the L∞-error estimates of mixed finite element methods for a semilinear elliptic control problem with an integral constraint.The state and co-state are approximated by the order one Raviart-Thomas mixed finite element space and the control variable is approximated by piecewise constant functions or piecewise linear functions.We derive some superconvergence results for the control variable and the state variables when the control is approximated by piecewise constant functions.Moreover,we derive L∞-error estimates for both the control variable and the state variables when the control is discretized by piecewise linear functions.Finally,some numerical examples are given to demonstrate the theoretical results.
基金supported by National Natural Science Foundation of China(Grant No.10971074)Foundation for Talent Introduction of Guangdong Provincial University,Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme(2008)Specialized Research Fund for the Doctoral Program of Higher Education(Grant No.20114407110009)
文摘In this paper,we investigate the superconvergence property of the numerical solution to a quadratic elliptic control problem by using mixed finite element methods.The state and co-state are approximated by the order k=1 Raviart-Thomas mixed finite element spaces and the control variable is approximated by piecewise constant functions.We prove the superconvergence error estimate of h3/2 in L2-norm between the approximated solution and the average L2 projection of the control.Moreover,by the postprocessing technique,a quadratic superconvergence result of the control is derived.
文摘A two-level discretization method for eigenvalue problems is studied.Compared to the standard Galerkin finite element discretization technique performed on a fine gridthis method discretizes the eigenvalue problem on a coarse grid and obtains an improved eigenvector(eigenvalue) approximation by solving only a linear problem on the fine grid (or two linear problemsfor the case of eigenvalue approximation of nonsymmetric problems). The improved solution has theasymptotic accuracy of the Galerkin discretization solution. The link between the method and theiterated Galerkin method is established. Error estimates for the general nonsymmetric case arederived.
文摘In this study,the effect of different sampling rates(i.e.observation recording interval)on the Precise Point Positioning(PPP)solutions in terms of accuracy was investigated.For this purpose,a field test was carried out inÇorum province,Turkey,on 11 September 2019.Within this context,a Geodetic Point(GP)was established and precisely coordinated.A static GNSS measurement was occupied on the GP for about 4-hour time at 0.10 second(s)/10 Hz measurement intervals with the Trimble R10 geodetic grade GNSS receiver.The original observation file was converted to RINEX format and then decimated into the different data sampling rates as 0.2 s,0.5 s,1 s,5 s,10 s,30 s,60 s,and 120 s.All these RINEX observation files were submitted to the Canadian Spatial Reference System-Precise Point Positioning(CSRS-PPP)online processing service the day after the data collection date by choosing both static and kinematic processing options.In this way,PPP-derived static coordinates,and the kinematic coordinates of each measurement epoch were calculated.The PPP-derived coordinates obtained from each decimated sampling intervals were compared to known coordinates of the GP for northing,easting,2D position,and height components.According to the static and kinematic processing results,high data sampling rates did not change the PPP solutions in terms of accuracy when compared to the results obtained using lower sampling rates.The results of this study imply that it was not necessary to collect GNSS data with high-rate intervals for many surveying projects requiring cm-level accuracy.
文摘Discontinuous deformation analysis(DDA)has been widely applied for the simulation of block systems that have many discontinuous surfaces.The penalty method is utilized to ensure that there are no penetrations between blocks.A linear polynomial function for displacement leads to a constant stress for a block,which cannot precisely describe the stress field within the block.Therefore,a high-order polynomial displacement function and a flue mesh are always used to improve the precision of the stress field.However,these means are not practical for simulating block systems that have many contacts.In this paper,the contact-stress-based stress recovery methods are proposed for DDA.High-precision solutions for the contact stresses on the boundaries of the blocks are utilized.The first-order Gaussian point of a block is the block's centroid,where the constant stress obtained via DDA is of higher precision.The high-precision solutions for the stresses are utilized in the least squares method to recover a single block's inner stress field.The proposed methods enhance the resolution of the stress field inside a single block without increasing the computational effort in the main iterative process for displacement in DDA.Numerical examples are simulated using both the finite element method(FEM)with a fine mesh and the proposed DDA program.The recovered DDA results can accurately describe the distribution of the stresses in a single block and,in some areas,have the same precision as the FEM results.Moreover,the precision of the proposed methods improves as the gradient of the contact stress on the boundary decreases.
文摘Abstract. In this paper which is motivated by computation on parallel machine, we showthat the superconvergence results of the finite element method(FEM) with Lagrange mul-tipliers based on domain decomposition method (DDM) with nonmatching grids can becarried over to parabolic problems. The main idea of this paper is to achieve the combina-tion of parallel computational method with the higher accuracy technique by interpolationfinite element postprocessing.
