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On the strength of polycrystals of boron nitride dense modifications

JOURNAL OF SUPERHARD MATERIALS 2009年第3期31卷 165-171页

作者： Golovchan, V. T. Natl Acad Sci Ukraine Bakul Inst Superhard Mat UA-04074 Kiev Ukraine

An analytical algorithm for the calculation of stresses in polycrystals of boron nitride dense modifications has been described. The relations established between the tensile and compression strength have been based on the Griffith fracture hypothesis for a biaxial stressed state. The effect has been taken into account of technological residual thermal stresses, which are formed in wurtzitic boron nitride (wBN) grains in sintering at the stage of cooling because of the thermal expansion anisotropy, on the strength of wBN.

关键词： analytical algorithm polycrystal cubic boron nitride wurtzitic boron nitride tensile strength compression strength

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Analytic solution of GPS atmospheric sounding refraction angles

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EARTH PLANETS AND SPACE 2004年第6期56卷 573-587页

作者： Awange, JL Fukuda, Y Takemoto, S Wickert, J Aoyama, Y Kyoto Univ Dept Geophys Sakyo Ku Kyoto 6068502 Japan Geoforschungszentrum Potsdam Div 1 Kinemat & Dynam Earth D-14473 Potsdam Germany Kyoto Univ Radio Ctr Space & Atmospher Kyoto 6110011 Japan

The nonlinear system of equations for solving GPS atmospheric sounding's bending angles are normally solved using Newton's method. Because of the nonlinear nature of the equations, Newton's method applies linearization and iterations. The method assumes the refraction angle to be small enough such that the dependency of the doppler shift on these angles are linear. The bending angles are then solved iteratively. Since the approach assumes the dependency of doppler shift on bending angles to be linear, which in actual sense is not, some small nonlinearity error is incurred. The Newton's iterative method is often used owing to the bottleneck of solving in exact form the nonlinear system of equations for bending angles. By converting this system of trigonometric nonlinear equations into algebraic, the present contribution proposes an analytic (algebraic) algorithm for solving the bending angles and presents the geometry of the solution space. The algorithm is tested by computing bending angles of three CHAMP occultation data and the results compared to those of iterative Newton's approach. Occultation 133 of 3rd May 2002 is selected as it occurred during diurnal solar radiation maximum past afternoon. During this time, the effect of ionospheric noise is high. Occultations number 3 of 14th May 2001 and number 6 of 2nd February 2002 were selected since they occurred past mid-night, a time of low solar activity and thus less effect of ionospheric noise. The results for occultation 133 of 3rd May 2002 indicate that the nonlinearity errors in bending angles increase with decrease in height to a maximum absolute value of 0.00069degrees (0.1%) for the region 5-40 km during period of high solar activity. Such nonlinearity errors are shown to impact significantly on the computed impact parameters to which the bending angles are referred. During low solar activity period, the nonlinearity error was relatively small for occultation number 3 of 14th May 2001 with maximum absolute

关键词： nonlinearity Sylvester resultant reduced Groebner basis analytical algorithm

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Analysis for Rotation Orthogonality of a Dynamically Adjusting Generalized Gough-Stewart Parallel Manipulator 10th

Analysis for Rotation Orthogonality of a Dynamically Adjusti...

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10th International Conference on Intelligent Robotics and Applications (ICIRA

作者： Tong, ZhiZhong Chen, Tao Peng, Lei Jiang, Hongzhou He, Fengjing Harbin Inst Technol Dept Mechatron Engn Harbin 150001 Peoples R China

ISBN: (纸本)9783319652924;9783319652917

A Gough-Stewart parallel manipulator using point decoupled design method is orthogonal only at a single point, which means that it has small high-precision workspace. It is hard to break through its' restriction to be applied in the field of engineer applications with larger workspace. This paper formulates the problem to guarantee continuous orthogonality when the manipulator rotating along the z-axis, called rotation orthogonality. Compared to traditional optimum, the rotation orthogonality leads to better performances with enlarged workspace. A class of dynamically adjusting generalized Gough-Stewart parallel manipulators (DAGGSPM) is proposed. The dynamically adjusting mechanism for rotation orthogonality and the related algorithm are deduced analytically. Through analysis of three typical cases and numerical verifications, the results show that a DAGGSPM can pave the way for high-precision applications with large scale workspace including laser weapon pointing, scanning microscopes and integrated circuit fabrication.

关键词： Dynamically adjusting generalized Gough-Stewart parallel manipulators Rotation orthogonality A pair of circular hyperboloids analytical algorithm Optimum design

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THE PRELIMINARY INQUIRY OF CHLOROPHYLL-A INVERSION ALGORIHTMS APPLICABLE TO GUANTING RESERVOIR

THE PRELIMINARY INQUIRY OF CHLOROPHYLL-A INVERSION ALGORIHTM...

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IEEE International Geoscience and Remote Sensing Symposium (IGARSS)

作者： Xie, Fei Guo, Ziqi Tian, Ye Liu, Caixia Lei, Xia Chinese Acad Sci Inst Remote Sensing Applicat State Key Lab Remote Sensing Sci Beijing 100101 Peoples R China Beijing Normal Univ Chinese Acad Sci Inst Remote Sensing & Digital Earth Beijing 100101 Peoples R China

ISBN: (纸本)9781479911141

Chlorophyll-a is an important index of entrophication. A large number of scholars have engaged in studying Chl-a inversion methodologies in the heavily polluted case II waters. However, the low-level-polluted case II waters haven't been paid enough attentions. In this study, we chose Guanting Reservoir, China, a low-level-polluted case II water area, as our study field. Then, we modeled three algorithms (original three-band algorithm, enhanced three-band algorithm and analytical algorithm) to retrieve Chl-a concentration. The results show that the Chl-a concentration predicted by the enhanced three-band algorithm is much more correlated with the measured Chl-a concentration (R2=0.843, RMSE=1.98) than the original three-band algorithm (R2=0.802, RMSE=2.15) and analytical algorithm (R2=0.836, RMSE=2.24). So, the enhanced three-band algorithm is the most applicable method of these three algorithms and has the potential applied in the inversion of Chl-a concentration in low-level-polluted case II waters.

关键词： case II water low-level polluted original three-band algorithm enhanced three-band algorithm analytical algorithm

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Inverse Kinematics algorithm for 7-DOF Manipulator with Offset and Its Application 8

Inverse Kinematics Algorithm for 7-DOF Manipulator with Offs...

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8th International Conference on Robotics, Control and Automation (ICRCA)

作者： Yang, XiaoFeng Jiang, ZhiYong Hu, JiangTao Wang, ChunLei Yang, Feng China Elect Technol Grp Corp Res Inst 21 Shanghai Peoples R China

ISBN: (纸本)9798350344738;9798350344721

The main inverse kinematics algorithms for the conventional 7-DOF robotic arm are analytical and numerical methods based on the optimal solution of the Jacobi matrix. The numerical method based on the optimal solution of the Jacobian matrix has no special requirements for the configuration of the manipulator, but the inverse kinematics solution of the 7-DOF manipulator with redundant degrees of freedom has the disadvantages of large amount of calculation and can only find a single solution. Compared with the conventional analytical method, the geometric relationship solution has the characteristics of fast speed and many solution sets, but the conventional analytical method is not suitable for the manipulator configuration with offset in this paper. Therefore, this paper proposes a new inverse kinematics method combining the advantages of the two algorithms, which solves the problem of solving the offset arm. In the solution process, joint and position constraints are added to ensure the accuracy and effectiveness of the solution.

关键词： robotic arm seven degrees of freedom analytical algorithm inverse kinematics

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Allowable Capacity Calculation of Distributed Generation in Different Distribution Network

Allowable Capacity Calculation of Distributed Generation in ...

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Asian Conference on Energy, Power and Transportation Electrification (ACEPT)

作者： Su, Yu Zhou, Niancheng Wang, Qianggang Wang, Tao Chongqing Univ State Key Lab Power Transmiss Equipment & Syst Se Chongqing Peoples R China Nanyang Technol Univ Singapore Singapore

ISBN: (纸本)9781538609712

With the distributed generation (DG) infiltrated distribution network gradually, determining the allowable capacity of DG quickly under different distribution network is the key to design and safe operation. According to the steady-state voltage, current and short circuit current of the feeder with DG, a practical analysis algorithm of DG allowable capacity for radial grid and single ring grid is given in this paper, considering the constraints of the voltage amplitude, voltage rising rate, line current and breaking current of breaker. Then taking the Shenzhen grid as example, the DG allowable capacities of radial grid and single ring grid are calculated, verifying the feasibility of the DG allowable capacity algorithm.

关键词： distributed generation allowable capacity distribution network analytical algorithm

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Scattering of Electromagnetic Waves by a PEC Bar Grating with a Nonlinear Dielectric Filling of its Slits

Scattering of Electromagnetic Waves by a PEC Bar Grating wit...

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IEEE International Conference on Mathematical Methods in Electromagnetic Theory (MMET)

作者： Kochetova, Lyudmila A. NASU Inst Radiophys & Elect Dept Quasi Opt IRE NASU Kharkov Ukraine

An analytical algorithm for solution of the diffraction problem on the PEC bars grating with a nonlinear dielectric filling of its slits is constructed. It is based on the solution of the diffraction problem on the PE... 详细信息

ISBN: (纸本)9781509019564

关键词： Nonlinear dielectric filling Kerr-type nonlinearity PEC bars grating analytical algorithm

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TANGENT DEVELOPABLE SURFACES ELEMENTS IN THIN-WALLED STRUCTURES 8

TANGENT DEVELOPABLE SURFACES ELEMENTS IN THIN-WALLED STRUCTU...

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8th International Conference on Textile Composites and Inflatable Structures (STRUCTURAL MEMBRANES)

作者： Belyaeva, Zoya V. Berestova, Svetlana A. Mityushov, Evgeny A. Ural Fed Univ Ekaterinburg 620049 Russia

ISBN: (纸本)9788494690990

This report demonstrates the capabilities of an advanced research area of the applied mathematics, i.e., computational geometry to be applied for shaping dimensional structures. Vector-matrix models are provided to purpose of piecewise-smooth structures modelling by surface elements with zero Gaussian curvature (elements of developable surfaces). The elements of tangent developable surface scan be built on the directing curves pieces located arbitrarily in space. The paper presents an analytical algorithm for drawing a cutting for the tangent developable surface element with two specified directing curves and the edge of regression known. An analytic algorithm for the curve on tangent developable surface development via the parametric equations of the edge of regression and the curve itself is obtained based on the tangent developable surface edge of regression development algorithm.

关键词： tangent developable surface surface development analytical algorithm

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analytical calculation formulas for capacities of classical and classical-quantum channels

Analytical calculation formulas for capacities of classical ...

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IEEE International Symposium on Information Theory (ISIT)

作者： Hayashi, Masahito Southern Univ Sci & Technol Shenzhen Inst Quantum Sci & Engn Guangdong Prov Key Lab Quantum Sci & Engn Shenzhen 518055 Peoples R China Int Quantum Acad SIQA Shenzhen 518048 Peoples R China Nagoya Univ Grad Sch Math Nagoya Aichi 4648602 Japan

ISBN: (纸本)9781665421607;9781665421591

We derive an analytical calculation formula for the channel capacity of a classical channel without any iteration while its existing algorithms require iterations and the number of iteration depends on the required precision level. Hence, our formula is its first analytical formula without any iteration. We apply the obtained formula to examples and see how the obtained formula works in these examples.

关键词： mutual information maximization channel capacity analytical algorithm

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A analytical Method of Trajectory Prediction Considering J₂ Perturbations and Including Short-Period Terms 4

A Analytical Method of Trajectory Prediction Considering J<s...

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4th International Conference on Control, Automation and Robotics (ICCAR)

作者： Geng Linyu Wu Nan Meng Fankun Han Jiaying Informat Engn Univ Zhengzhou Henan Peoples R China

ISBN: (纸本)9781538663387

In order to take into account the accuracy and effectiveness of ballistic missile trajectory prediction, an analytical method considering perturbations and including short periodic terms is proposed. At the same time, an error propagation analysis method combined with unscented transformation is constructed to solve the problem that Kepler root number is not differentiable and the partial derivative matrix is difficult to be calculated in the analysis method. Simulation results show that the relative error of the proposed algorithm is less than 5%, its accuracy is comparable to that of the high precision numerical method, much higher than that of the traditional analytic method, and the computation speed is 7 times of that of the latter. The proposed algorithm has higher cost-efficiency ratio.

关键词： component trajectory prediction unscented transformation J(2) perturbation analytical algorithm short-period term

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