A new quadrilateral finite element IQ4 is developed for the free vibration of carbon nanotube-reinforced composite(CNTRC)perforated plates with a central cutout.By enriching the membrane part and incorporating a proje...A new quadrilateral finite element IQ4 is developed for the free vibration of carbon nanotube-reinforced composite(CNTRC)perforated plates with a central cutout.By enriching the membrane part and incorporating a projected shear technique,the IQ4 element is proposed to address the known limitations of the standard Q4 element,such as shear locking and limited consistency in the coupling ofmembrane-bending components.The proposed element is formulated within the FSDT-based framework and assessed through benchmark tests to verify its convergence and accuracy.The governing equations are obtained via theweak formofHamilton’s principle.Particular attention is given to the influence of carbon nanotube volume fraction,distribution patterns,and boundary conditions on the fundamental frequency response of CNTRC plates with cutouts.In addition,a parametric study is conducted to assess the influence of cutout geometric configuration,shape,and size ratios on the vibrational response of the CNTRC plate.The numerical results demonstrate that the formulated IQ4 element provides stable and accurate estimations of natural frequencies,even in the presence of a cutout and the coupled effects of the non-uniform distribution of reinforcement through the plate thickness.The developed formulation is expected to contribute to the structural design and optimization of advanced lightweight systems,particularly in aerospace and mechanical engineering applications.展开更多
We present a non-Markovian master equation for a qubit interacting with a general reservoir, which is derived according to the Nakajima-Zwanzig and the time convolutionless projection operator technique. The non-Marko...We present a non-Markovian master equation for a qubit interacting with a general reservoir, which is derived according to the Nakajima-Zwanzig and the time convolutionless projection operator technique. The non-Markovian solutions and Markovian solution of dynamical decay of a qubit are compared. The results indicate the validity of non-Markovian approach in different coupling regimes and also show that the Markovian master equation may not precisely describe the dynamics of an open quantum system in some situation. The non-Markovian solutions may be effective for many qubits independently interacting with the heated reservoirs.展开更多
BACKGROUND The data obtained on the anatomical knowledge of the tracheobronchial system can be used for diagnosis,treatment and interventional interventions in areas such as anesthesia,thoracic surgery,pulmonary physi...BACKGROUND The data obtained on the anatomical knowledge of the tracheobronchial system can be used for diagnosis,treatment and interventional interventions in areas such as anesthesia,thoracic surgery,pulmonary physiology.AIM To determine the tracheobronchial branching angles in pediatric and adult populations by using the multislice computed tomography(CT)and minimum intensity projection(MinIP)technique,which is a non-invasive method.METHODS Our study was carried out retrospectively.Patients who underwent contrast and non-contrast CT examination,whose anatomically and pathophysiologically good tracheobronchial system and lung parenchyma images were obtained,were included in the study.Measurements were made in the coronal plane of the lung parenchyma.In the coronal plane,right main bronchus-left main bronchus angle,right upper lobe bronchus-intermedius bronchus angle,right middle lobe bronchus-right lower lobe bronchus angle,left upper lobe bronchus-left lower lobe bronchus angle were measured.RESULTS The study population consisted of 1511 patients,753 pediatric(mean age:13.4±4.3;range:1-18 years)and 758 adults(mean age:54.3±17.3;range:19-94 years).In our study,tracheal bifurcation angle was found to be 73.3°±13.7°(59.6°-87°)in the whole population.In the pediatric group,the right-left main coronal level was found to be higher in boys compared to girls(74.6°±12.9°vs 71.2°±13.9°,P=0.001).In the adult group,the right-left main coronal level was found to be lower in males compared to females(71.9°±12.9°vs 75.8°±14.7°,P<0.001).CONCLUSIONS Our study,with the number of 1511 patients,is the first study in the literature with the largest number of patient populations including pediatric and adult demographic data,measuring the angle values of the tracheobronchial system using multislice CT and MinIP technique.Study data will not only be a guide during invasive procedures,but it can also guide studies to be done with imaging methods.展开更多
A cautious projection BFGS method is proposed for solving nonconvex unconstrained optimization problems.The global convergence of this method as well as a stronger general convergence result can be proven without a gr...A cautious projection BFGS method is proposed for solving nonconvex unconstrained optimization problems.The global convergence of this method as well as a stronger general convergence result can be proven without a gradient Lipschitz continuity assumption,which is more in line with the actual problems than the existing modified BFGS methods and the traditional BFGS method.Under some additional conditions,the method presented has a superlinear convergence rate,which can be regarded as an extension and supplement of BFGS-type methods with the projection technique.Finally,the effectiveness and application prospects of the proposed method are verified by numerical experiments.展开更多
We derive higher order magneto-hydrodynamic （MHD） equations from a microscopic picture using pro-jection and perturbation formalism. In an application to Hartmann flow we find velocity profiles flattening towards th...We derive higher order magneto-hydrodynamic （MHD） equations from a microscopic picture using pro-jection and perturbation formalism. In an application to Hartmann flow we find velocity profiles flattening towards the center at the onset of turbulence in hydrodynamic limit. Comparison with the system under the effect of a uniform magnetic field yields difference in the onset of turbulence consistent with observations, showing that the presence of magnetic field inhibits onset of instability or turbulence. The laminar-turbulent transition is demonstrated in a phase transition plot of the development in time of the relative average velocities vs. Reynolds number showing a sharp increase of the relative average velocity at the transition point as determined by the critical Reynolds number.展开更多
For the constrained generalized Hamiltonian system with dissipation, by introducing Lagrange multiplier and using projection technique, the Lie group integration method was presented, which can preserve the inherent s...For the constrained generalized Hamiltonian system with dissipation, by introducing Lagrange multiplier and using projection technique, the Lie group integration method was presented, which can preserve the inherent structure of dynamic system and the constraint-invariant. Firstly, the constrained generalized Hamiltonian system with dissipative was converted to the non-constraint generalized Hamiltonian system, then Lie group integration algorithm for the non-constraint generalized Hamiltonian system was discussed, finally the projection method for generalized Hamiltonian system with constraint was given. It is found that the constraint invariant is ensured by projection technique, and after introducing Lagrange multiplier the Lie group character of the dynamic system can't be destroyed while projecting to the constraint manifold. The discussion is restricted to the case of holonomic constraint. A presented numerical example shows the effectiveness of the method.展开更多
How＇s the effect of technical import actually？ The latter stage evaluation to technique import project is necessary to get the answer. Therefore, the latter stage evaluation to technique import project is not equal ...How＇s the effect of technical import actually？ The latter stage evaluation to technique import project is necessary to get the answer. Therefore, the latter stage evaluation to technique import project is not equal to the latter stage evaluation to general construction projects, it doesn＇t emphasize particularly on its economic profits but the performance of the digest, generalization, improvement and redevelopment of the imported technique.展开更多
This paper reviewed the concepts of Project Evaluation Review Technique and<span style="font-family:Verdana;"> Critical Path Method in project management with practical examples. The methods and succes...This paper reviewed the concepts of Project Evaluation Review Technique and<span style="font-family:Verdana;"> Critical Path Method in project management with practical examples. The methods and success of quantitative decision-making approaches in project management through t</span><span style="font-family:Verdana;">he use of project evaluation review technique and the critical path method as regards project duration and critical activities of a project, were discussed. The review found that while both methods are effective in achieving success in project management, the relationship and connectivity of activities involved in a project life cycle are key aspects. The paper concludes that the project evaluation review technique is more effective when the duration of the project is uncertain, while the critical path method is effective when the project’s end time is certain. The paper, therefore, recommends that to achieve maximum operative efficiency in utilizing resources in project management, p</span><span style="font-family:Verdana;">rior to commencing the execution of a project, all required resources to cover every activity must be assembled and prioritized to eliminate interruptions that could bring delay and unnecessary cost implications. Again, policies focused on improving project execution should be implemented in developing nations to minimize the many cases of failed and delayed projects. Subsequently, stakeholders in projects must be given the right, under the law, to prosecute the government, its agencies and/or the executors of projects for failure to execute a project on schedule.</span>展开更多
Objective To assess the diagnostic value of the airway post-processing technique of multi-slice spiral CT(MSCT)in accessory cardiac bronchus(ACB)and to improve the understanding of this disease.Methods The original MS...Objective To assess the diagnostic value of the airway post-processing technique of multi-slice spiral CT(MSCT)in accessory cardiac bronchus(ACB)and to improve the understanding of this disease.Methods The original MSCT axial images and various post-processing reconstructed images of 9 ACB cases were retrospectively analyzed.Airway post-processing techniques,including multi-planar reformation(MPR),minimum intensity projection(MinIP),volume rendering technique(VRT),CT virtual endoscopy(CTVE)and tissue transition projection(TTP),were employed.Three-dimensional recombination images of bronchial trees were obtained and classified according to the Mangiulea classification.Results Among the 9 cases with ACB,there were 6 cases of accessory-lobed type,3 cases of long diverticular type,and no cases of short diverticular type.The lateral axial images,MPR,MinIP,VRT,CTVE,and TTP all clearly displayed ACB.Among the 6 cases of accessorylobed type,there were 5 cases with accessory lobe dysplasia and one case with pneumonia in an accessory lobe.One case was complicated with accessory lobe emphysema.Among the 3 cases with long diverticular type ACB,one had pneumonia.Among the 9 cases,there was 1 case with old tuberculous focus,1 case with pulmonary fibrous focus,1 case with pleural thickening and adhesion,and 1 case with tracheal diverticulum.Conclusion The airway post-processing technique of MSCT can not only clarify the diagnosis,origin and classification of ACB,but also measure the opening diameter,length and distance to the tracheal carina of ACB.It guides clinical treatment and tracheoscopy,etc,and can be used as the preferred examination method for ACB.展开更多
文摘A new quadrilateral finite element IQ4 is developed for the free vibration of carbon nanotube-reinforced composite(CNTRC)perforated plates with a central cutout.By enriching the membrane part and incorporating a projected shear technique,the IQ4 element is proposed to address the known limitations of the standard Q4 element,such as shear locking and limited consistency in the coupling ofmembrane-bending components.The proposed element is formulated within the FSDT-based framework and assessed through benchmark tests to verify its convergence and accuracy.The governing equations are obtained via theweak formofHamilton’s principle.Particular attention is given to the influence of carbon nanotube volume fraction,distribution patterns,and boundary conditions on the fundamental frequency response of CNTRC plates with cutouts.In addition,a parametric study is conducted to assess the influence of cutout geometric configuration,shape,and size ratios on the vibrational response of the CNTRC plate.The numerical results demonstrate that the formulated IQ4 element provides stable and accurate estimations of natural frequencies,even in the presence of a cutout and the coupled effects of the non-uniform distribution of reinforcement through the plate thickness.The developed formulation is expected to contribute to the structural design and optimization of advanced lightweight systems,particularly in aerospace and mechanical engineering applications.
基金Project supported by the Natural Science Foundation of Hunan Province of China (Grant No. 09JJ6011)the Natural Science Foundation of the Education Department of Hunan Province of China (Grant Nos. 06C652 and 07C528)
文摘We present a non-Markovian master equation for a qubit interacting with a general reservoir, which is derived according to the Nakajima-Zwanzig and the time convolutionless projection operator technique. The non-Markovian solutions and Markovian solution of dynamical decay of a qubit are compared. The results indicate the validity of non-Markovian approach in different coupling regimes and also show that the Markovian master equation may not precisely describe the dynamics of an open quantum system in some situation. The non-Markovian solutions may be effective for many qubits independently interacting with the heated reservoirs.
文摘BACKGROUND The data obtained on the anatomical knowledge of the tracheobronchial system can be used for diagnosis,treatment and interventional interventions in areas such as anesthesia,thoracic surgery,pulmonary physiology.AIM To determine the tracheobronchial branching angles in pediatric and adult populations by using the multislice computed tomography(CT)and minimum intensity projection(MinIP)technique,which is a non-invasive method.METHODS Our study was carried out retrospectively.Patients who underwent contrast and non-contrast CT examination,whose anatomically and pathophysiologically good tracheobronchial system and lung parenchyma images were obtained,were included in the study.Measurements were made in the coronal plane of the lung parenchyma.In the coronal plane,right main bronchus-left main bronchus angle,right upper lobe bronchus-intermedius bronchus angle,right middle lobe bronchus-right lower lobe bronchus angle,left upper lobe bronchus-left lower lobe bronchus angle were measured.RESULTS The study population consisted of 1511 patients,753 pediatric(mean age:13.4±4.3;range:1-18 years)and 758 adults(mean age:54.3±17.3;range:19-94 years).In our study,tracheal bifurcation angle was found to be 73.3°±13.7°(59.6°-87°)in the whole population.In the pediatric group,the right-left main coronal level was found to be higher in boys compared to girls(74.6°±12.9°vs 71.2°±13.9°,P=0.001).In the adult group,the right-left main coronal level was found to be lower in males compared to females(71.9°±12.9°vs 75.8°±14.7°,P<0.001).CONCLUSIONS Our study,with the number of 1511 patients,is the first study in the literature with the largest number of patient populations including pediatric and adult demographic data,measuring the angle values of the tracheobronchial system using multislice CT and MinIP technique.Study data will not only be a guide during invasive procedures,but it can also guide studies to be done with imaging methods.
基金supported by the Guangxi Science and Technology base and Talent Project(AD22080047)the National Natural Science Foundation of Guangxi Province(2023GXNFSBA 026063)+1 种基金the Innovation Funds of Chinese University(2021BCF03001)the special foundation for Guangxi Ba Gui Scholars.
文摘A cautious projection BFGS method is proposed for solving nonconvex unconstrained optimization problems.The global convergence of this method as well as a stronger general convergence result can be proven without a gradient Lipschitz continuity assumption,which is more in line with the actual problems than the existing modified BFGS methods and the traditional BFGS method.Under some additional conditions,the method presented has a superlinear convergence rate,which can be regarded as an extension and supplement of BFGS-type methods with the projection technique.Finally,the effectiveness and application prospects of the proposed method are verified by numerical experiments.
文摘We derive higher order magneto-hydrodynamic （MHD） equations from a microscopic picture using pro-jection and perturbation formalism. In an application to Hartmann flow we find velocity profiles flattening towards the center at the onset of turbulence in hydrodynamic limit. Comparison with the system under the effect of a uniform magnetic field yields difference in the onset of turbulence consistent with observations, showing that the presence of magnetic field inhibits onset of instability or turbulence. The laminar-turbulent transition is demonstrated in a phase transition plot of the development in time of the relative average velocities vs. Reynolds number showing a sharp increase of the relative average velocity at the transition point as determined by the critical Reynolds number.
文摘For the constrained generalized Hamiltonian system with dissipation, by introducing Lagrange multiplier and using projection technique, the Lie group integration method was presented, which can preserve the inherent structure of dynamic system and the constraint-invariant. Firstly, the constrained generalized Hamiltonian system with dissipative was converted to the non-constraint generalized Hamiltonian system, then Lie group integration algorithm for the non-constraint generalized Hamiltonian system was discussed, finally the projection method for generalized Hamiltonian system with constraint was given. It is found that the constraint invariant is ensured by projection technique, and after introducing Lagrange multiplier the Lie group character of the dynamic system can't be destroyed while projecting to the constraint manifold. The discussion is restricted to the case of holonomic constraint. A presented numerical example shows the effectiveness of the method.
文摘How＇s the effect of technical import actually？ The latter stage evaluation to technique import project is necessary to get the answer. Therefore, the latter stage evaluation to technique import project is not equal to the latter stage evaluation to general construction projects, it doesn＇t emphasize particularly on its economic profits but the performance of the digest, generalization, improvement and redevelopment of the imported technique.
文摘This paper reviewed the concepts of Project Evaluation Review Technique and<span style="font-family:Verdana;"> Critical Path Method in project management with practical examples. The methods and success of quantitative decision-making approaches in project management through t</span><span style="font-family:Verdana;">he use of project evaluation review technique and the critical path method as regards project duration and critical activities of a project, were discussed. The review found that while both methods are effective in achieving success in project management, the relationship and connectivity of activities involved in a project life cycle are key aspects. The paper concludes that the project evaluation review technique is more effective when the duration of the project is uncertain, while the critical path method is effective when the project’s end time is certain. The paper, therefore, recommends that to achieve maximum operative efficiency in utilizing resources in project management, p</span><span style="font-family:Verdana;">rior to commencing the execution of a project, all required resources to cover every activity must be assembled and prioritized to eliminate interruptions that could bring delay and unnecessary cost implications. Again, policies focused on improving project execution should be implemented in developing nations to minimize the many cases of failed and delayed projects. Subsequently, stakeholders in projects must be given the right, under the law, to prosecute the government, its agencies and/or the executors of projects for failure to execute a project on schedule.</span>
文摘Objective To assess the diagnostic value of the airway post-processing technique of multi-slice spiral CT(MSCT)in accessory cardiac bronchus(ACB)and to improve the understanding of this disease.Methods The original MSCT axial images and various post-processing reconstructed images of 9 ACB cases were retrospectively analyzed.Airway post-processing techniques,including multi-planar reformation(MPR),minimum intensity projection(MinIP),volume rendering technique(VRT),CT virtual endoscopy(CTVE)and tissue transition projection(TTP),were employed.Three-dimensional recombination images of bronchial trees were obtained and classified according to the Mangiulea classification.Results Among the 9 cases with ACB,there were 6 cases of accessory-lobed type,3 cases of long diverticular type,and no cases of short diverticular type.The lateral axial images,MPR,MinIP,VRT,CTVE,and TTP all clearly displayed ACB.Among the 6 cases of accessorylobed type,there were 5 cases with accessory lobe dysplasia and one case with pneumonia in an accessory lobe.One case was complicated with accessory lobe emphysema.Among the 3 cases with long diverticular type ACB,one had pneumonia.Among the 9 cases,there was 1 case with old tuberculous focus,1 case with pulmonary fibrous focus,1 case with pleural thickening and adhesion,and 1 case with tracheal diverticulum.Conclusion The airway post-processing technique of MSCT can not only clarify the diagnosis,origin and classification of ACB,but also measure the opening diameter,length and distance to the tracheal carina of ACB.It guides clinical treatment and tracheoscopy,etc,and can be used as the preferred examination method for ACB.
