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Showers with large zenith angles observed in emulsion chambers

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Science China Mathematics 1997年第9期40卷 985-989页

作者：任敬儒陆穗苓解卫王承瑞何瑁张乃健 Institute of High Energy Physics Chinese Academy of SciencesBeijing 100039China Department of Physics Shandong UniversityJinan 250100China

Showers with large zenith angles are observed in emulsion chambers exposed at *** intensity of high energy muons is given and the multicore showers with large zenith angles are *** is indicated that a new phenomenon m... 详细信息

关键词： emulsion chamber showers with large zenith angles multicore showers.

Preoperative calculation of angles of vision and working area in laparoscopic surgery to treat a giant hiatal hernia

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World Journal of Gastrointestinal Surgery 2021年第12期13卷 1638-1650页

作者： Francisco Javier Perez Lara Rogelio Zubizarreta Jimenez Francisco Javier Moya Donoso Jose Manuel Hernández Gonzalez Tatiana Prieto-Puga Arjona Arturo del Rey Moreno Maria Pitarch Martinez Surgery Service Antequera HospitalRincón de la Victoria 29730MálagaSpain DOXA Microfluidics Rincon de la Victoria 29738MálagaSpain

BACKGROUND Giant hiatal hernias still pose a major challenge to digestive surgeons,and their repair is sometimes a highly complex *** is usually performed by laparoscopy,while the role of the thoracoscopic approach has yet to be clearly *** To preoperatively detect patients with a giant hiatal hernia in whom it would not be safe to perform laparoscopic surgery and who,therefore,would be candidates for a thoracoscopic *** In the present study,using imaging test we preoperatively simulate the field of vision of the camera and the working area(instrumental access)that can be obtained in each patient when the laparoscopic approach is *** From data obtained,we can calculate the access angles that will be obtained in a preoperative computerised axial tomography coronal section,according to the location of the *** also provide the formula for performing the angle calculations If the trocars are placed in loss common situations,thus enabling us to determine the visibility and manoeuvrability for any position of the *** The working area determines the cases in which we can operate safely and those in which certain areas of the hernia cannot be accessed,which is when the thoracoscopic approach would be safer.

关键词： Hiatal hernia angles Approach Laparoscopy Thoracoscopy

A N0TE ON THE EXPRESSION FOR THE ROTATI0N TENS0R IN TERMS OF EULER·angles

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Applied Mathematics and Mechanics(English Edition) 1982年第1期3卷 121-125页

作者：程沅生 Shanghai University of Technology Department of Mechanical Engineering

It is pointed out in this paper that the deri-vation of the expression for the rotation tensor interms of Euler angles by *** is *** point out Kochin′s deficit on this problemis advantageous for perfecting the concep... 详细信息

关键词： A N0TE ON THE EXPRESSION FOR THE ROTATI0N TENS0R IN TERMS OF EULER angles

Topics on Solid angles

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Journal of Applied Mathematics and Physics 2019年第10期7卷 2423-2439页

作者： L. C. M. Amaral Dallas TX USA

The purpose of the present work is to derive some solutions for several solid angle cases via a fundamental formula which gives the solid angle for an isosceles triangle. From this formula the solid angle of pyramids is derived but, unlike other presentations, it is shown in a format similar to that of the well-known cone case. Besides the regular polygon cases (straight pyramids), solid angles of some other plane closed curves are calculated. The fundamental formula also leads to some interesting properties showing the not simple behavior of solid angles with the observer point on the curve itself, as it depends on how the observer arrived there. The question of the equi-Ω surfaces is also discussed and calculated in simple cases.

关键词： Solid angles Pyramid Solid angles Electric Field Flux Equi-Ω Surfaces

Effect of tapered angles in an artery on distribution of blood flow pressure with gravity considered

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Journal of Biomedical Science and Engineering 2013年第12期6卷 14-20页

作者： Wenying Mu Shanguang Chen Changsheng Ma Jianzeng Dong Department of Cardiology Beijing Anzhen Hospital Capital Medical University Beijing China National Key Laboratory of Human Factors Engineering China Astronaut Research and Training Center Beijing China

The tapered angles of an artery significantly influence the local hemodynamics. However, as gravity is considered, little is known about the effect of tapered angles on the hemodynamics. In this study, we explored whether the effect of tapered angles on the distribution of blood flow pressure (DBFP) differed with gravity considered or not. Numerical simulations of the DBFP in a single vessel were performed based on such tapered angles as 0°, 0.5° and 1°. In the model used for simulation, gravity was introduced as a body force. We obtained the following simulations: i) The larger the tapered angles were, the better distributed the blood flow pressure;ii) The tapered effect was an important factor leading to nonlinearity in blood flow pressure;iii) Gravity affected DBFP coupling with the tapered angles, yet independently influenced the dimension of the DBFP. At the same time, the effective intensity of gravity decreased with the increase of tapered angles.

关键词： Tapered angles Distribution of Blood Flow Pressure (DBFP) Gravity Numerical Simulation

Torsion in Groups of Integral Triangles

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Advances in Pure Mathematics 2013年第1期3卷 116-120页

作者： Will Murray Department of Mathematics and Statistics California State University Long Beach USA

Let 0<γ<π be a fixed pythagorean angle. We study the abelian group Hr of primitive integral triangles (a,b,c) for which the angle opposite side c is γ. Addition in Hr is defined by adding the angles β opposite sid... 详细信息

Let 0angles (a,b,c) for which the angle opposite side c is γ. Addition in Hr is defined by adding the angles β opposite side b and modding out by π-γ. The only Hr for which the structure is known is Hπ/2, which is free abelian. We prove that for generalγ, Hr has an element of order two iff 2(1- cosγ) is a rational square, and it has elements of order three iff the cubic (2cosγ)x3-3x2+1=0 has a rational solution 0

关键词： Abelian Groups Cubic Equations Examples Free Abelian Geometric Constructions Group Theory Integral Triangles Law of Cosines Primitive Pythagorean angles Pythagorean Triangles Pythagorean Triples Rational Squares Three-Torsion Torsion Torsion-Free Two-Torsion Triangle Geometry

Effects of yaw-roll coupling ratio on lateraldirectional aerodynamic characteristics

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Chinese Journal of Aeronautics 2019年第2期32卷 272-280页

作者： Lin SHEN Da HUANG Genxing WU College of Aerospace Engineering Nanjing University of Aeronautics and Astronautics

Experimental investigation of large amplitude yaw-roll coupled oscillations was conducted in a low-speed wind tunnel using an aircraft configuration model. A special test rig was designed and constructed to provide different coupled motions from low to high angles of attack.A parameter ‘‘coupling ratio" was introduced to indicate the extent of yaw-roll coupling. At each pitch angle, seven coupling ratios were designed to study the yaw-roll coupling effects on the lateraldirectional aerodynamic characteristics systematically. At high angles of attack, the damping characteristics of yawing and rolling moments drastically varied with coupling ratios. In the coupled motions with the rotation taking place about the wind axis, the lateral-directional aerodynamic moments exhibited unsteady characteristics and were different from the ‘‘quasi-steady" results of the rotary balance tests. The calculated results of the traditional aerodynamic derivative method were also compared with the experimental data. At low and very high angles of attack, the aerodynamic derivative method was applicative. However, within a wide range of angles of attack, the calculated results of aerodynamic derivative method were inconsistent with the experimental data, due to the drastic changes of damping characteristics of lateral-directional aerodynamic moments with yaw-roll coupling ratios.

关键词： High angles of attack Hysteresis Lateral-directional aerodynamic characteristics Unsteady Yaw-roll coupling

Joint frequency, 2D AOA and polarization estimation using fourth-order cumulants

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Science China(Technological Sciences) 2000年第3期43卷 297-303页

作者：王建英陈天琪 University of Electronic Science and Technology of China Chengdu 610054 China

Based on fourth-order cumulant and ESPRIT algorithm, a novel joint frequency, two-dimensional angle of arrival (2D AOA) and the polarization estimation method of incoming multiple independent spatial narrow-band non-Gaussian signals in arbitrary Gaussian noise environment are proposed . The array is composed of crossed dipoles parallel to the coordinate axes. The crossed dipole positions are arbitrarily distributed. Computer simulation confirms its feasibility.

关键词： frequency two-dimensional angles of arrival polarization ESPRIT fourth-order cumulant.

Comparison of the dynamic response of a saturated soil between two models

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Science China Earth Sciences 2004年第6期47卷 551-558页

作者： LIN Mian Institute of Mechanics Chinese Academy of SciencesBeijing100080China

By comparing the dynamic responses of saturated soil to Biots and Yamamotos models, the properties of the two models have be pointed out. First of all, an analysis has been made for energy loss of each model from the basic equations. Then the damping of elastic waves in coarse sand and fine sand with loading frequency and soils parameters have been calculated and the representation of viscous friction and Coulomb friction in the two models has been con-cluded. Finally, the variations of loading wave damping and stress phase angles with water depth and soils parameters have been obtained as loading waves range in ocean waves.

关键词： models of marine sediment, elastic waves, phase angles of stress field.