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Furnace Temperature Curve Optimization Model Based on Differential Evolution Algorithm
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作者 Yiming Cheng 《Journal of Electronic Research and Application》 2024年第4期64-80,共17页
When soldering electronic components onto circuit boards,the temperature curves of the reflow ovens across different zones and the conveyor belt speed significantly influence the product quality.This study focuses on ... When soldering electronic components onto circuit boards,the temperature curves of the reflow ovens across different zones and the conveyor belt speed significantly influence the product quality.This study focuses on optimizing the furnace temperature curve under varying settings of reflow oven zone temperatures and conveyor belt speeds.To address this,the research sequentially develops a heat transfer model for reflow soldering,an optimization model for reflow furnace conditions using the differential evolution algorithm,and an evaluation and decision model combining the differential evolution algorithm with the Technique for Order Preference by Similarity to Ideal Solution(TOPSIS)method.This approach aims to determine the optimal furnace temperature curve,zone temperatures of the reflow oven,and the conveyor belt speed. 展开更多
关键词 Furnace temperature curve Difference equations differential evolution algorithms TOPSIS methods
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CONTINUOUS DEPENDENCE OF THE SOLUTIONS OF IMPULSIVE DIFFERENTIAL EQUATIONS ON THE INITIAL CONDITIONS AND BARRIER CURVES 被引量:2
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作者 K.G.Dishlieva 《Acta Mathematica Scientia》 SCIE CSCD 2012年第3期1035-1052,共18页
The basic objects of investigation in this article are nonlinear impulsive dif- ferential equations. The impulsive moments coincide with the moments of meeting of the integral curve and some of the so-called barrier c... The basic objects of investigation in this article are nonlinear impulsive dif- ferential equations. The impulsive moments coincide with the moments of meeting of the integral curve and some of the so-called barrier curves. For such type of equations, suf- ficient conditions are found under which the solutions are continuously dependent on the perturbations with respect to the initial conditions and barrier curves. The results are applied to a mathematical model of population dynamics. 展开更多
关键词 Impulsive differential equations initial condition barrier curves continuous dependence population dynamics
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Positioning-control Based on Trapezoidal Velocity Curve for High-precision Basis Weight Control Valve 被引量:3
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作者 Bo Wang Wei Tang +1 位作者 JiXian Dong Feng Wang 《Paper And Biomaterials》 2017年第2期42-50,共9页
Traditionally, basis weight control valve is driven by a constant frequency pulse signal. Therefore, it is difficult for the valve to match the control precision of basis weight. Dynamic simulation research using Matl... Traditionally, basis weight control valve is driven by a constant frequency pulse signal. Therefore, it is difficult for the valve to match the control precision of basis weight. Dynamic simulation research using Matlab/Simulink indicates that there is much more overshoot and fluctuating during the valve-positioning process. In order to improve the valve-positioning precision, the control method of trapezoidal velocity curve was studied. The simulation result showed that the positioning steady-state error was less than 0.0056%, whereas the peak error was less than 0.016% by using trapezoidal velocity curve at 10 positioning steps. A valve-positioning precision experimental device for the stepper motor of basis weight control valve was developed. The experiment results showed that the error ratio of 1/10000 positioning steps was 4% by using trapezoidal velocity curve. Furthermore, the error ratio of 10/10000 positioning steps was 0.5%. It proved that the valve-positioning precision of trapezoidal velocity curve was much higher than that of the constant frequency pulse signal control strategy. The new control method of trapezoidal velocity curve can satisfy the precision requirement of 10000 steps. 展开更多
关键词 high-precision basis weight control valve precision positioning control trapezoidal velocity curve Matlab/Simulink simulation
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Lift-Off Effect of Koch and Circular Differential Pickup Eddy Current Probes
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作者 Guolong Chen Zheng Cao +3 位作者 Shuaishuai Zhang Ji Wei Wei Gao Wuyin Jin 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2024年第2期283-293,共11页
A flexible or planar eddy current probe with a differential structure can suppress the lift-off noise during the inspection of defects.However,the extent of the lift-off effect on differential probes,including differe... A flexible or planar eddy current probe with a differential structure can suppress the lift-off noise during the inspection of defects.However,the extent of the lift-off effect on differential probes,including different coil structures,varies.In this study,two planar eddy current probes with differential pickup structures and the same size,Koch and circular probes,were used to compare lift-off effects.The eddy current distributions of the probes perturbed by 0°and 90°cracks were obtained by finite element analysis.The analysis results show that the 90°crack can impede the eddy current induced by the Koch probe even further at relatively low lift-off distance.The peak-to-peak values of the signal output from the two probes were compared at different lift-off distances using finite element analysis and experimental methods.In addition,the effects of different frequencies on the lift-off were studied experimentally.The results show that the signal peak-to-peak value of the Koch probe for the inspection of cracks in 90°orientation is larger than that of the circular probe when the lift-off distance is smaller than 1.2 mm.In addition,the influence of the lift-off distance on the peak-to-peak signal value of the two probes was studied via normalization.This indicates that the influence becomes more evident with an increase in excitation frequency.This research discloses the lift-off effect of differential planar eddy current probes with different coil shapes and proves the detection merit of the Koch probe for 90°cracks at low lift-off distances. 展开更多
关键词 Eddy current testing differential pickup probe Fractal Koch curve Flexible eddy current probe
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Near-surface velocity inversion from Rayleigh wave dispersion curves based on a differential evolution simulated annealing algorithm
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作者 Yaojun Wang Hua Wang +3 位作者 Xijun Wu Keyu Chen Sheng Liu Xiaodong Deng 《Artificial Intelligence in Geosciences》 2021年第1期35-46,共12页
The utilization of urban underground space in a smart city requires an accurate understanding of the underground structure.As an effective technique,Rayleigh wave exploration can accurately obtain information on the s... The utilization of urban underground space in a smart city requires an accurate understanding of the underground structure.As an effective technique,Rayleigh wave exploration can accurately obtain information on the subsurface.In particular,Rayleigh wave dispersion curves can be used to determine the near-surface shear-wave velocity structure.This is a typical multiparameter,high-dimensional nonlinear inverse problem because the velocities and thickness of each layer must be inverted simultaneously.Nonlinear methods such as simulated annealing(SA)are commonly used to solve this inverse problem.However,SA controls the iterative process though temperature rather than the error,and the search direction is random;hence,SA always falls into a local optimum when the temperature setting is inaccurate.Specifically,for the inversion of Rayleigh wave dispersion curves,the inversion accuracy will decrease with an increasing number of layers due to the greater number of inversion parameters and large dimension.To solve the above problems,we convert the multiparameter,highdimensional inverse problem into multiple low-dimensional optimizations to improve the algorithm accuracy by incorporating the principle of block coordinate descent(BCD)into SA.Then,we convert the temperature control conditions in the original SA method into error control conditions.At the same time,we introduce the differential evolution(DE)method to ensure that the iterative error steadily decreases by correcting the iterative error direction in each iteration.Finally,the inversion stability is improved,and the proposed inversion method,the block coordinate descent differential evolution simulated annealing(BCDESA)algorithm,is implemented.The performance of BCDESA is validated by using both synthetic data and field data from western China.The results show that the BCDESA algorithm has stronger global optimization capabilities than SA,and the inversion results have higher stability and accuracy.In addition,synthetic data analysis also shows that BCDESA can avoid the problems of the conventional SA method,which assumes the S-wave velocity structure in advance.The robustness and adaptability of the algorithm are improved,and more accurate shear-wave velocity and thickness information can be extracted from Rayleigh wave dispersion curves. 展开更多
关键词 Simulated annealing differential evolution Block coordinate descent Surface wave dispersion curve Nonlinear inversion
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Combined detection of serum tumor markers for differential diagnosis of solid lesions located at the pancreatic head 被引量:27
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作者 Liao, Quan Zhao, Yu-Pei +3 位作者 Yang, Ying-Chi Li, Li-Jun Long, Xiao Han, Shao-Mei 《Hepatobiliary & Pancreatic Diseases International》 SCIE CAS 2007年第6期641-645,共5页
BACKGROUND: The differential diagnosis of solid lesions located at the pancreatic head is very important for choosing therapies and setting up surgical tactics. This study was designed to evaluate the clinical signifi... BACKGROUND: The differential diagnosis of solid lesions located at the pancreatic head is very important for choosing therapies and setting up surgical tactics. This study was designed to evaluate the clinical significance of combined measurement of multiple serum tumor markers and the application of the receiver-operating characteristic (ROC) curves in the differential diagnosis of solid lesions located at the pancreatic head. METHODS: The serum levels of CA19-9, CA242, CA50 and carcinoembryonic antigen (CEA) in 112 patients with carcinoma of the pancreatic head and 38 patients with focal chronic pancreatitis in the pancreatic head were measured with ELISA. The sensitivity, specificity, positive likelihood ratio (PLR) and negative likelihood ratio (NLR) of the four serum tumor markers were calculated. The ROC curves for the four serum tumor markers were constructed and the area under the curve (AUC) was calculated. RESULTS: The AUCs of CA19-9, CA242, CA50 and CEA were 0.805, 0.749, 0.738 and 0.705; the PLRs were 1.91, 3.43, 5.09 and 5.46; and the NLRs were 0.41, 0.56, 0.59 and 0.71, respectively. Combined measurements increased the diagnostic specificity, and parallel combined testing increased the diagnostic sensitivity. CONCLUSIONS: Combined measurement of serum tumor markers CA19-9, CA242, CA50 and CEA is valuable in differential diagnosis of solid lesions located at the pancreatic head, and CA19-9 has the best diagnostic ability. Combined measurements can increase the specificity of diagnosis. Evaluation with the ROC curve is better than the sensitivity or specificity alone and the results are more integrated and objective. 展开更多
关键词 pancreatic neoplasm tumor markers ROC curve differential diagnosis
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Predictive model for stage-discharge curve in compound channels with vegetated floodplains 被引量:8
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作者 刘超 刘兴年 杨克君 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2014年第12期1495-1508,共14页
The governing equation of the discharge per unit width, derived from the flow continuity equation and the momentum equation in the vegetated compound chan- nel, is established. The analytical solution to the discharge... The governing equation of the discharge per unit width, derived from the flow continuity equation and the momentum equation in the vegetated compound chan- nel, is established. The analytical solution to the discharge per unit width is presented, including the effects of bed friction, lateral momentum transfer, drag force, and secondary flows. A simple' but available numerical integral method, i.e., the compound trapezoidM formula, is used to calculate the approximate solutions of the sub-area discharge and the total discharge. A comparison with the published experimental data from the U. K. Flood Channel Facility (UK-FCF) demonstrates that this model is capable of predicting not only the stage-discharge curve but also the sub-area discharge in the vegetated com- pound channel. The effects of the two crucial parameters, i.e., the divided number of the integral interval and the secondary flow coefficient, on the total discharge are discussed and analyzed. 展开更多
关键词 stage-discharge curve compound trapezoidal formula compound channel overbank flow VEGETATION
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Secure and efficient elliptic curve cryptography resists side-channel attacks 被引量:8
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作者 Zhang Tao Fan Mingyu Zheng Xiaoyu 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2009年第3期660-665,共6页
An embedded cryptosystem needs higher reconfiguration capability and security. After analyzing the newly emerging side-channel attacks on elliptic curve cryptosystem (ECC), an efficient fractional width-w NAF (FWNA... An embedded cryptosystem needs higher reconfiguration capability and security. After analyzing the newly emerging side-channel attacks on elliptic curve cryptosystem (ECC), an efficient fractional width-w NAF (FWNAF) algorithm is proposed to secure ECC scalar multiplication from these attacks. This algorithm adopts the fractional window method and probabilistic SPA scheme to reconfigure the pre-computed table, and it allows designers to make a dynamic configuration on pre-computed table. And then, it is enhanced to resist SPA, DPA, RPA and ZPA attacks by using the random masking method. Compared with the WBRIP and EBRIP methods, our proposals has the lowest total computation cost and reduce the shake phenomenon due to sharp fluctuation on computation performance. 展开更多
关键词 elliptic curve cryptography side channel attack simple power attack differential power attack refined power analysis zero-point power analysis.
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Pancreatic carcinoma coexisting with chronic pancreatitis versus tumor-forming pancreatitis:Diagnostic utility of the time-signal intensity curve from dynamic contrast-enhanced MR imaging 被引量:29
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作者 Yoshitsugu Tajima Tamotsu Kuroki +3 位作者 Ryuji Tsutsumi Ichiro Isomoto Masataka Uetani Takashi Kanematsu 《World Journal of Gastroenterology》 SCIE CAS CSCD 2007年第6期858-865,共8页
AIM: To evaluate the ability of the time-signal intensity curve (TIC) of the pancreas obtained from dynamic contrast-enhanced magnetic resonance imaging (MRI) for differentiation of focal pancreatic masses, especially... AIM: To evaluate the ability of the time-signal intensity curve (TIC) of the pancreas obtained from dynamic contrast-enhanced magnetic resonance imaging (MRI) for differentiation of focal pancreatic masses, especially pancreatic carcinoma coexisting with chronic pancreatitis and tumor-forming pancreatitis. METHODS: Forty-eight consecutive patients who underwent surgery for a focal pancreatic mass, including pancreatic ductal carcinoma (n = 33), tumor-forming pancreatitis (n = 8), and islet cell tumor (n = 7), were reviewed. Five pancreatic carcinomas coexisted with longstanding chronic pancreatitis. The pancreatic TICs were obtained from the pancreatic mass and the pancreatic parenchyma both proximal and distal to the mass lesion in each patient, prior to surgery, and were classified into 4 types according to the time to a peak: 25 s and 1, 2, and 3 min after the bolus injection of contrast material, namely, type-Ⅰ, Ⅱ, Ⅲ, and Ⅳ, respectively, and were then compared to the corresponding histological pancreatic conditions. RESULTS: Pancreatic carcinomas demonstrated type-Ⅲ (n = 13) or Ⅳ (n = 20) TIC. Tumor-forming pancreatitis showed type-Ⅱ (n = 5) or Ⅲ (n = 3) TIC. All islet cell tumors revealed type-Ⅰ. The type-Ⅳ TIC was only recognized in pancreatic carcinoma, and the TIC of carcinoma always depicted the slowest rise to a peak among the 3 pancreatic TICs measured in each patient, even in patients with chronic pancreatitis.CONCLUSION: Pancreatic TIC from dynamic MRI provides reliable information for distinguishing pancreatic carcinoma from other pancreatic masses, and may enable us to avoid unnecessary pancreatic surgery and delays in making a correct diagnosis of pancreatic carcinoma, especially, in patients with longstanding chronic pancreatitis. 展开更多
关键词 Pancreatic carcinoma Chronic pancreatitis Focal pancreatic mass Tumor-forming pancreatitis differential diagnosis Dynamic magnetic resonance imaging Time-signal intensity curve
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Extension of covariant derivative(Ⅱ): From flat space to curved space 被引量:4
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作者 Ya-Jun Yin 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2015年第1期88-95,共8页
This paper extends the classical covariant deriva tive to the generalized covariant derivative on curved sur faces. The basement for the extension is similar to the pre vious paper, i.e., the axiom of the covariant fo... This paper extends the classical covariant deriva tive to the generalized covariant derivative on curved sur faces. The basement for the extension is similar to the pre vious paper, i.e., the axiom of the covariant form invariabil ity. Based on the generalized covariant derivative, a covari ant differential transformation group with orthogonal duality is set up. Through such orthogonal duality, tensor analy sis on curved surfaces is simplified intensively. Under the covariant differential transformation group, the differential invariabilities and integral invariabilities are constructed on curved surfaces. 展开更多
关键词 Tensor analysis on curved surfaces Classicalcovariant derivative and generalized covariant derivative Axiom of the covariant form invariability Covariant differ-ential transformation group differential invariabilities andintegral invariabilities
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Multi-Degree Reduction of Bézier Curves with Distance and Energy Optimization 被引量:2
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作者 Xuli Han Jing Yang 《Journal of Applied Mathematics and Physics》 2016年第1期8-15,共8页
In this paper, we propose a new approach to the problem of degree reduction of Bézier curves based on the given endpoint constraints. A differential term is added for the purpose of controlling the smoothness to ... In this paper, we propose a new approach to the problem of degree reduction of Bézier curves based on the given endpoint constraints. A differential term is added for the purpose of controlling the smoothness to a certain extent. Considering the adjustment of second derivative in curve design, a modified objective function including two parts is constructed here. One part is a kind of measure of the distance between original high order Bézier curve and degree-reduced curve. The other part represents the second derivative of degree-reduced curve. We tackle two kinds of conditions which are position vector constraint and tangent vector constraint respectively. The explicit representations of unknown points are presented. Some examples are illustrated to show the influence of the differential terms to approximation and smoothness effect. 展开更多
关键词 Bézier curve Degree Reduction Endpoint Constraint differential Constraint L2-Norm
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Flow-Induced Vibration of A Nonlinearly Restrained Curved Pipe Conveying Fluid
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作者 王琳 倪樵 黄玉盈 《海洋工程:英文版》 EI 2004年第3期347-356,共10页
Investigated in this study is the flow induced vibration of a nonlinearly restrained curved pipe conveying fluid. The nonlinear equation of motion is derived by equilibrium of forces on microelement of the system und... Investigated in this study is the flow induced vibration of a nonlinearly restrained curved pipe conveying fluid. The nonlinear equation of motion is derived by equilibrium of forces on microelement of the system under consideration. The spatial coordinate of the system is discretized by DQM (differential quadrature method). On the basis of the boundary conditions, the dynamic equation is solved by the Newton Raphson iteration method. The numerical solutions reveal several complex dynamic motions for the variation of the fluid velocity parameter, such as limit cycle motion, buckling and so on. The result obtained also shows that the sub parameter regions corresponding to the several motions may change with the variation of some parameters of the curved pipe. The present study supplies a new reference for investigating the nonlinear dynamic response of some other structures. 展开更多
关键词 curved pipe conveying fluid flow induced vibration limit cycle motion motion constraint differential quadrature method
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The Relative Biologic Effectiveness versus Linear Energy Transfer Curve as a Cell Trait
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作者 Quoc T. Luu Paul DuChateau 《Applied Mathematics》 2013年第11期23-27,共5页
The magnitude of biological response varies with different radiation types. Using Linear Energy Transfer (LET) to differentiate types of incident radiation beam, the Relative Biologic Effectiveness (RBE) as a function... The magnitude of biological response varies with different radiation types. Using Linear Energy Transfer (LET) to differentiate types of incident radiation beam, the Relative Biologic Effectiveness (RBE) as a function of LET (RBE-LET) was found to have a characteristic shape with a peak around LET values 100 - 200 eV/nm. This general feature is believed to be a property of the incident beam. Our systems engineering model, however, suggests that the shape of the RBE-LET curve is a cell trait, a property of the cell. Like any other trait, phenotypic variations result from interactions of the genes and their context. State-space block diagram of the differential equation model suggests the genes are those in the DNA double strand break (dsb) repair pathway;and the context is cellular stress responsing to DNA damage by both external stimuli and internal redox state. At a deeper level, the block diagram suggests cell using mathematical calculations in its decision-making when facing a stress signal. The MRN protein complex, in particular, may perform addition to count the degree of DNA twisting for the homeostatic regulation of DNA supercoiling. The ATM protein may act as a feedback amplifier. 展开更多
关键词 RBE-LET curve CELL TRAIT Systems BIOLOGY Fourier Analysis Stochastic differential Equation
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Subdomain Chebyshev Spectral Method for 2D and 3D Numerical Differentiations in a Curved Coordinate System
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作者 Bing Zhou Graham Heinson Aixa Rivera-Rios 《Journal of Applied Mathematics and Physics》 2015年第3期358-370,共13页
A new numerical approach, called the “subdomain Chebyshev spectral method” is presented for calculation of the spatial derivatives in a curved coordinate system, which may be employed for numerical solutions of part... A new numerical approach, called the “subdomain Chebyshev spectral method” is presented for calculation of the spatial derivatives in a curved coordinate system, which may be employed for numerical solutions of partial differential equations defined in a 2D or 3D geological model. The new approach refers to a “strong version” against the “weak version” of the subspace spectral method based on the variational principle or Galerkin’s weighting scheme. We incorporate local nonlinear transformations and global spline interpolations in a curved coordinate system and make the discrete grid exactly matches geometry of the model so that it is achieved to convert the global domain into subdomains and apply Chebyshev points to locally sampling physical quantities and globally computing the spatial derivatives. This new approach not only remains exponential convergence of the standard spectral method in subdomains, but also yields a sparse assembled matrix when applied for the global domain simulations. We conducted 2D and 3D synthetic experiments and compared accuracies of the numerical differentiations with traditional finite difference approaches. The results show that as the points of differentiation vector are larger than five, the subdomain Chebyshev spectral method significantly improve the accuracies of the finite difference approaches. 展开更多
关键词 Numerical DIFFERENTIATION CHEBYSHEV Spectral Method curved COORDINATE System ARBITRARY TOPOGRAPHY
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Free-Form Laminated Doubly-Curved Shells and Panels of Revolution Resting on Winkler-Pasternak Elastic Foundations: A 2-D GDQ Solution for Static and Free Vibration Analysis
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作者 Francesco Tornabene Alessandro Ceruti 《World Journal of Mechanics》 2013年第1期1-25,共25页
This work presents the static and dynamic analyses of laminated doubly-curved shells and panels of revolution resting on Winkler-Pasternak elastic foundations using the Generalized Differential Quadrature (GDQ) method... This work presents the static and dynamic analyses of laminated doubly-curved shells and panels of revolution resting on Winkler-Pasternak elastic foundations using the Generalized Differential Quadrature (GDQ) method. The analyses are worked out considering the First-order Shear Deformation Theory (FSDT) for the above mentioned moderately thick structural elements. The effect of the shell curvatures is included from the beginning of the theory formulation in the kinematic model. The solutions are given in terms of generalized displacement components of points lying on the middle surface of the shell. Simple Rational Bézier curves are used to define the meridian curve of the revolution structures. The discretization of the system by means of the GDQ technique leads to a standard linear problem for the static analysis and to a standard linear eigenvalue problem for the dynamic analysis. Comparisons between the present formulation and the Reissner-Mindlin theory are presented. Furthermore, GDQ results are compared with those obtained by using commercial programs. Very good agreement is observed. Finally, new results are presented in order to investtigate the effects of the Winkler modulus, the Pasternak modulus and the inertia of the elastic foundation on the behavior of laminated shells of revolution. 展开更多
关键词 Doubly-curved SHELLS of REVOLUTION Rational BÉZIER curves LAMINATED Composite SHELLS Winkler-Pasternak Foundation First-Order Shear Deformation Theory Generalized differential Quadrature Method
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GL(n, R)-Equivalence of a Pair of Curves in Terms of Invariants
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作者 Yasemin Sagiroglu Ziya Yapar 《Journal of Mathematics and System Science》 2016年第1期16-22,共7页
In this paper, the generator set of R 〈 x1,x2 〉G is obtained in according to the group G = Gl(n,R). The conditions of G = Gl(n, R) -equivalence of a pair of curves are found in terms of G = Gl(n, R)-invariants... In this paper, the generator set of R 〈 x1,x2 〉G is obtained in according to the group G = Gl(n,R). The conditions of G = Gl(n, R) -equivalence of a pair of curves are found in terms of G = Gl(n, R)-invariants. And the independence of GL(n, R) -invariants is shown. 展开更多
关键词 GL(n R) -invariants differential invariants of curves equivalence of curves.
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Modified Algorithm for Solving Linear Integro-Differential Equations of the Second Kind
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作者 M. Al-Towaiq Ahmed Kasasbeh 《American Journal of Computational Mathematics》 2017年第2期157-165,共9页
In this paper, a modified algorithm is proposed for solving linear integro-differential equations of the second kind. The main idea is based on applying Romberg extrapolation algorithm (REA), on Trapezoidal rule. In a... In this paper, a modified algorithm is proposed for solving linear integro-differential equations of the second kind. The main idea is based on applying Romberg extrapolation algorithm (REA), on Trapezoidal rule. In accordance with the computational perspective, the comparison has shown that Adomian decomposition approach is more effective to be utilized. The numerical results show that the modified algorithm has been successfully applied to the linear integro-differential equations and the comparisons with some existing methods appeared in the literature reveal that the modified algorithm is more accurate and convenient. 展开更多
关键词 Algorithm Integro-differential EQUATIONS trapezoidal RULE Romberg EXTRAPOLATION
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铝合金型材挤压弯曲一体化成形技术研究进展
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作者 赵国群 孙宇彤 喻俊荃 《塑性工程学报》 CAS CSCD 北大核心 2024年第4期46-55,共10页
相比于直型材,铝合金弯曲型材更适用于日益复杂的部件形状并能更好地满足轻量化需求,具有提升部件结构强度和刚度、节约空间及增加工业设计自由度等优点,在汽车、高铁和航空航天等领域具有广泛用途。相较于传统冷弯成形技术,挤压弯曲一... 相比于直型材,铝合金弯曲型材更适用于日益复杂的部件形状并能更好地满足轻量化需求,具有提升部件结构强度和刚度、节约空间及增加工业设计自由度等优点,在汽车、高铁和航空航天等领域具有广泛用途。相较于传统冷弯成形技术,挤压弯曲一体化成形技术在生产弯曲型材方面具有流程短、精度高、缺陷少等优点,因而受到广泛关注。重点综述了基于外部弯曲装置和材料差速流动的挤压弯曲一体化成形技术的研究进展,分析并总结了不同挤压弯曲一体化成形技术的原理及发展现状,对比了不同挤压弯曲一体化成形技术的优缺点,最后展望未来发展趋势及其研究方向。 展开更多
关键词 铝合金 弯曲型材 挤压弯曲一体化 外部弯曲 材料差速流动
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基于混合驱动的分离罗拉运动轨迹规划研究
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作者 张玉香 吕传硕 +1 位作者 杨淑启 王延蒙 《纺织器材》 2024年第4期6-10,共5页
针对当前棉精梳机分离接合机构运动输出特性固定、振动大等问题,分析棉精梳机分离罗拉分离接合工艺,确定分离罗拉运动的位移关键点位置,根据差动轮系的运动规律提出交替驱动和分段驱动2种动力分配方案,并采用三次样条曲线作为交替驱动... 针对当前棉精梳机分离接合机构运动输出特性固定、振动大等问题,分析棉精梳机分离罗拉分离接合工艺,确定分离罗拉运动的位移关键点位置,根据差动轮系的运动规律提出交替驱动和分段驱动2种动力分配方案,并采用三次样条曲线作为交替驱动位移曲线、S型加减速曲线作为分段驱动位移曲线,通过对比分析得到最佳分离罗拉运动轨迹。指出:当设定棉纤维长度为30 mm时,2种驱动方案均能满足分离接合要求;采用混合驱动机构对分离罗拉高速正反转运动进行分解,实现伺服电机混合驱动分离罗拉,其运动性能更佳。 展开更多
关键词 混合驱动 棉精梳机 分离罗拉 差动轮系 三次样条曲线 S型加减速曲线 分离接合
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肺癌七项自身抗体联合检测在肺结节良恶性鉴别诊断中的应用价值
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作者 侯卫科 《实用癌症杂志》 2024年第8期1297-1300,共4页
目的探讨肺癌七项自身抗体检测在肺结节良恶性鉴别诊断中的临床价值。方法选取肺癌患者45例作为观察组,另选同期收治的良性肺结节患者45例作为对照组,所有患者均采集血液进行抑癌基因53(p53)、干细胞转录因子2(SOX2)、肿瘤睾丸抗原7(GAG... 目的探讨肺癌七项自身抗体检测在肺结节良恶性鉴别诊断中的临床价值。方法选取肺癌患者45例作为观察组,另选同期收治的良性肺结节患者45例作为对照组,所有患者均采集血液进行抑癌基因53(p53)、干细胞转录因子2(SOX2)、肿瘤睾丸抗原7(GAGE7)、蛋白基因产物9.5(PGP9.5)、人癌抗原(Cage)、黑色素瘤抗原A1(MAGEA1)、肿瘤抗原4-5(Gbu4-5)检测,比较2组各抗体间差异;并依据肺癌肿瘤分期分为Ⅰ~Ⅱ、Ⅲ~Ⅳ期患者,比较2组各抗体间水平差异;绘制ROC曲线,分析各抗体及联合检测鉴别诊断良恶性肺结节的临床价值。结果观察组p53、SOX2、GAGE7、PGP9.5、Cage、MAGEA1、Gbu4-5水平高于对照组,差异有统计学意义(P<0.05)。45例肺癌患者中Ⅰ~Ⅱ期29例,Ⅲ~Ⅳ期16例;Ⅲ~Ⅳ期患者p53、SOX2、GAGE7、PGP9.5、Cage、MAGEA1、Gbu4-5水平高于Ⅰ~Ⅱ期患者,差异有统计学意义(P<0.05)。绘制ROC曲线显示,联合肺癌七项自身抗体检测鉴别诊断肺结节良恶性价值更高。结论肺癌七项自身抗体检测在肺结节良恶性鉴别诊断中价值高,可提高诊断灵敏度及特异度,有助于后续针对性治疗工作的开展。 展开更多
关键词 肺结节 良恶性鉴别 肺癌七项自身抗体 ROC曲线 诊断价值
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