This paper presents an efficient numerical technique for solving multi-term linear systems of fractional ordinary differential equations(FODEs)which have been widely used in modeling various phenomena in engineering a...This paper presents an efficient numerical technique for solving multi-term linear systems of fractional ordinary differential equations(FODEs)which have been widely used in modeling various phenomena in engineering and science.An approximate solution of the system is sought in the formof the finite series over the Müntz polynomials.By using the collocation procedure in the time interval,one gets the linear algebraic system for the coefficient of the expansion which can be easily solved numerically by a standard procedure.This technique also serves as the basis for solving the time-fractional partial differential equations(PDEs).The modified radial basis functions are used for spatial approximation of the solution.The collocation in the solution domain transforms the equation into a system of fractional ordinary differential equations similar to the one mentioned above.Several examples have verified the performance of the proposed novel technique with high accuracy and efficiency.展开更多
By studying the pile-formula and stress-wave methods (e.g., CASE method), the authors propose a new method for testing piles using the single-impact energy and P-S curves. The vibration and wave figures are recorded,...By studying the pile-formula and stress-wave methods (e.g., CASE method), the authors propose a new method for testing piles using the single-impact energy and P-S curves. The vibration and wave figures are recorded, and the dynamic and static displacements are measured by different transducers near the top of piles when the pile is im- pacted by a heavy hammer or micro-rocket. By observing the transformation coefficient of driving energy (total energy), the consumed energy of wave motion and vibration and so on, the vertical bearing capacity for single pile is measured and calculated. Then, using the vibration wave diagram, the dynamic relation curves between the force (P) and the displacement (S) is calculated and the yield points are determined. Using the static-loading test, the dynamic results are checked and the relative constants of dynamic-static P-S curves are determined. Then the sub- sidence quantity corresponding to the bearing capacity is determined. Moreover, the shaped quality of the pile body can be judged from the formation of P-S curves.展开更多
We report the discovery of an isolated millisecond pulsar M15O(J2129+1210O)from the globular cluster M15(NGC 7078)with a period of 11.06686 ms and a dispersion measure of~67.44 cm^(-3)pc.Its spin period is so close to...We report the discovery of an isolated millisecond pulsar M15O(J2129+1210O)from the globular cluster M15(NGC 7078)with a period of 11.06686 ms and a dispersion measure of~67.44 cm^(-3)pc.Its spin period is so close to the 10th harmonic of the bright pulsar M15A(~11.06647 ms)that it was missed in a previous pulsar search.We suggest adding the spectrum in the pulsar candidate diagnostic plot to identify new signals near the harmonics.M15O has the first spin frequency derivative and the second spin frequency derivative,being 1.79191(5)×10^(-14)Hz s^(-1)and 3.3133(6)×10^(-23)Hz s^(-2),respectively.Its projected distance from the optical center of M15 is the closest among all the pulsars in M15.The origin can be something from the center of the massive and core-collapsed globular cluster M15.展开更多
OBJECTIVE To evaluate the safety and effectiveness of robot-assisted percutaneous coronary intervention(R-PCI)compared to traditional manual percutaneous coronary intervention(M-PCI).METHODS This prospective,multicent...OBJECTIVE To evaluate the safety and effectiveness of robot-assisted percutaneous coronary intervention(R-PCI)compared to traditional manual percutaneous coronary intervention(M-PCI).METHODS This prospective,multicenter,randomized controlled,non-inferior clinical trial enrolled patients with coronary heart disease who met the inclusion criteria and had indications for elective percutaneous coronary intervention.Participants were randomly assigned to either the R-PCI group or the M-PCI group.Primary endpoints were clinical and technical success rates.Clinical success was defined as visually estimated residual post-percutaneous coronary intervention stenosis<30% with no 30-day major adverse cardiac events.Technical success in the R-PCI group was defined as successful completion of percutaneous coronary intervention using the ETcath200 robot-assisted system,without conversion to M-PCI in the event of a guidewire or balloon/stent catheter that was unable to cross the vessel or was poorly supported by the catheter.Secondary endpoints included total procedure time,percutaneous coronary intervention procedure time,fluoroscopy time,contrast volume,operator radiation exposure,air kerma,and dose-area product.RESULTS The trial enrolled 152 patients(R-PCI:73 patients,M-PCI:79 patients).Lesions were predominantly B2/C type(73.6%).Both groups achieved 100% clinical success rate.No major adverse cardiac events occurred during the 30-day follow-up.The R-PCI group had a technical success rate of 100%.The R-PCI group had longer total procedure and fluoroscopy times,but lower operator radiation exposure.The percutaneous coronary intervention procedure time,contrast volume,air kerma,and dose-area product were similar between the two groups.CONCLUSIONS For certain complex lesions,performing percutaneous coronary intervention using the ETcath200 robot-assisted system is safe and effective and does not result in conversion to M-PCI.展开更多
The airborne electromagnetic （AEM） method has a high sampling rate and survey flexibility. However, traditional numerical modeling approaches must use high-resolution physical grids to guarantee modeling accuracy, e...The airborne electromagnetic （AEM） method has a high sampling rate and survey flexibility. However, traditional numerical modeling approaches must use high-resolution physical grids to guarantee modeling accuracy, especially for complex geological structures such as anisotropic earth. This can lead to huge computational costs. To solve this problem, we propose a spectral-element （SE） method for 3D AEM anisotropic modeling, which combines the advantages of spectral and finite-element methods. Thus, the SE method has accuracy as high as that of the spectral method and the ability to model complex geology inherited from the finite-element method. The SE method can improve the modeling accuracy within discrete grids and reduce the dependence of modeling results on the grids. This helps achieve high-accuracy anisotropic AEM modeling. We first introduced a rotating tensor of anisotropic conductivity to Maxwell＇s equations and described the electrical field via SE basis functions based on GLL interpolation polynomials. We used the Galerkin weighted residual method to establish the linear equation system for the SE method, and we took a vertical magnetic dipole as the transmission source for our AEM modeling. We then applied fourth-order SE calculations with coarse physical grids to check the accuracy of our modeling results against a 1D semi-analytical solution for an anisotropic half-space model and verified the high accuracy of the SE. Moreover, we conducted AEM modeling for different anisotropic 3D abnormal bodies using two physical grid scales and three orders of SE to obtain the convergence conditions for different anisotropic abnormal bodies. Finally, we studied the identification of anisotropy for single anisotropic abnormal bodies, anisotropic surrounding rock, and single anisotropic abnormal body embedded in an anisotropic surrounding rock. This approach will play a key role in the inversion and interpretation of AEM data collected in regions with anisotropic geology.展开更多
基金funded by the National Key Research and Development Program of China(No.2021YFB2600704)the National Natural Science Foundation of China(No.52171272)the Significant Science and Technology Project of the Ministry of Water Resources of China(No.SKS-2022112).
文摘This paper presents an efficient numerical technique for solving multi-term linear systems of fractional ordinary differential equations(FODEs)which have been widely used in modeling various phenomena in engineering and science.An approximate solution of the system is sought in the formof the finite series over the Müntz polynomials.By using the collocation procedure in the time interval,one gets the linear algebraic system for the coefficient of the expansion which can be easily solved numerically by a standard procedure.This technique also serves as the basis for solving the time-fractional partial differential equations(PDEs).The modified radial basis functions are used for spatial approximation of the solution.The collocation in the solution domain transforms the equation into a system of fractional ordinary differential equations similar to the one mentioned above.Several examples have verified the performance of the proposed novel technique with high accuracy and efficiency.
基金Key Projects of Tenth Five-year Plan of Yunnan Province (54-02-02).
文摘By studying the pile-formula and stress-wave methods (e.g., CASE method), the authors propose a new method for testing piles using the single-impact energy and P-S curves. The vibration and wave figures are recorded, and the dynamic and static displacements are measured by different transducers near the top of piles when the pile is im- pacted by a heavy hammer or micro-rocket. By observing the transformation coefficient of driving energy (total energy), the consumed energy of wave motion and vibration and so on, the vertical bearing capacity for single pile is measured and calculated. Then, using the vibration wave diagram, the dynamic relation curves between the force (P) and the displacement (S) is calculated and the yield points are determined. Using the static-loading test, the dynamic results are checked and the relative constants of dynamic-static P-S curves are determined. Then the sub- sidence quantity corresponding to the bearing capacity is determined. Moreover, the shaped quality of the pile body can be judged from the formation of P-S curves.
基金supported by the National Key R&D Program of China No.2022YFC2205202,No.2020SKA0120100the National Natural Science Foundation of China(NSFC,grant Nos.12373032,12003047,11773041,U2031119,12173052,and 12173053)+2 种基金supported by the Youth Innovation Promotion Association of CAS(id.2018075,Y2022027 and 2023064)the CAS“Light of West China”Programsupported by the Science and Technology Program of Guizhou Province under project No.QKHPTRC-ZDSYS[2023]003 and QKHFQ[2023]003。
文摘We report the discovery of an isolated millisecond pulsar M15O(J2129+1210O)from the globular cluster M15(NGC 7078)with a period of 11.06686 ms and a dispersion measure of~67.44 cm^(-3)pc.Its spin period is so close to the 10th harmonic of the bright pulsar M15A(~11.06647 ms)that it was missed in a previous pulsar search.We suggest adding the spectrum in the pulsar candidate diagnostic plot to identify new signals near the harmonics.M15O has the first spin frequency derivative and the second spin frequency derivative,being 1.79191(5)×10^(-14)Hz s^(-1)and 3.3133(6)×10^(-23)Hz s^(-2),respectively.Its projected distance from the optical center of M15 is the closest among all the pulsars in M15.The origin can be something from the center of the massive and core-collapsed globular cluster M15.
基金supported by the National Key Research and Development Program of China(No.2022YFC3602500)Beijing High-level Public Health Technical Talents Construction Project(Discipline Leader-03-24)Beijing Hospitals Authority’s Ascent Plan(DFL20240601).
文摘OBJECTIVE To evaluate the safety and effectiveness of robot-assisted percutaneous coronary intervention(R-PCI)compared to traditional manual percutaneous coronary intervention(M-PCI).METHODS This prospective,multicenter,randomized controlled,non-inferior clinical trial enrolled patients with coronary heart disease who met the inclusion criteria and had indications for elective percutaneous coronary intervention.Participants were randomly assigned to either the R-PCI group or the M-PCI group.Primary endpoints were clinical and technical success rates.Clinical success was defined as visually estimated residual post-percutaneous coronary intervention stenosis<30% with no 30-day major adverse cardiac events.Technical success in the R-PCI group was defined as successful completion of percutaneous coronary intervention using the ETcath200 robot-assisted system,without conversion to M-PCI in the event of a guidewire or balloon/stent catheter that was unable to cross the vessel or was poorly supported by the catheter.Secondary endpoints included total procedure time,percutaneous coronary intervention procedure time,fluoroscopy time,contrast volume,operator radiation exposure,air kerma,and dose-area product.RESULTS The trial enrolled 152 patients(R-PCI:73 patients,M-PCI:79 patients).Lesions were predominantly B2/C type(73.6%).Both groups achieved 100% clinical success rate.No major adverse cardiac events occurred during the 30-day follow-up.The R-PCI group had a technical success rate of 100%.The R-PCI group had longer total procedure and fluoroscopy times,but lower operator radiation exposure.The percutaneous coronary intervention procedure time,contrast volume,air kerma,and dose-area product were similar between the two groups.CONCLUSIONS For certain complex lesions,performing percutaneous coronary intervention using the ETcath200 robot-assisted system is safe and effective and does not result in conversion to M-PCI.
基金financially supported by the Key Program of National Natural Science Foundation of China(No.41530320)China Natural Science Foundation for Young Scientists(No.41404093)+1 种基金Key National Research Project of China(Nos2016YFC0303100 and 2017YFC0601900)China Natural Science Foundation(No.41774125)
文摘The airborne electromagnetic （AEM） method has a high sampling rate and survey flexibility. However, traditional numerical modeling approaches must use high-resolution physical grids to guarantee modeling accuracy, especially for complex geological structures such as anisotropic earth. This can lead to huge computational costs. To solve this problem, we propose a spectral-element （SE） method for 3D AEM anisotropic modeling, which combines the advantages of spectral and finite-element methods. Thus, the SE method has accuracy as high as that of the spectral method and the ability to model complex geology inherited from the finite-element method. The SE method can improve the modeling accuracy within discrete grids and reduce the dependence of modeling results on the grids. This helps achieve high-accuracy anisotropic AEM modeling. We first introduced a rotating tensor of anisotropic conductivity to Maxwell＇s equations and described the electrical field via SE basis functions based on GLL interpolation polynomials. We used the Galerkin weighted residual method to establish the linear equation system for the SE method, and we took a vertical magnetic dipole as the transmission source for our AEM modeling. We then applied fourth-order SE calculations with coarse physical grids to check the accuracy of our modeling results against a 1D semi-analytical solution for an anisotropic half-space model and verified the high accuracy of the SE. Moreover, we conducted AEM modeling for different anisotropic 3D abnormal bodies using two physical grid scales and three orders of SE to obtain the convergence conditions for different anisotropic abnormal bodies. Finally, we studied the identification of anisotropy for single anisotropic abnormal bodies, anisotropic surrounding rock, and single anisotropic abnormal body embedded in an anisotropic surrounding rock. This approach will play a key role in the inversion and interpretation of AEM data collected in regions with anisotropic geology.
