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Time-frequency response spectrum of rotational ground motion and its application 被引量:16
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作者 Wei Che Qifeng Luo 《Earthquake Science》 CSCD 2010年第1期71-77,共7页
The rotational seismic motions are estimated from one station records of the 1999 Jiji (Chi-Chi), Taiwan, earthquake based on the theory of elastic plane wave propagation. The time-frequency response spectrum (TFRS... The rotational seismic motions are estimated from one station records of the 1999 Jiji (Chi-Chi), Taiwan, earthquake based on the theory of elastic plane wave propagation. The time-frequency response spectrum (TFRS) of the rotational motions is calculated and its characteristics are analyzed, then the TFRS is applied to analyze the damage mechanism of one twelve-storey frame concrete structure. The results show that one of the ground motion components can not reflect the characteristics of the seismic motions completely; the characteristics of each component, especially rotational motions, need to be studied. The damage line of the structure and TFRS of ground motion are important for seismic design, only the TFRS of input seismic wave is suitable, the structure design is reliable. 展开更多
关键词 Jiji (Chi-Chi) earthquake ground motion rotational component time-frequency response spectrum damage line
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A New Method on Resolving the Rotation in the Plane of Skew Bridges 被引量:1
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作者 KANG Jun-tao ZHENG Jun-jie WANG Guo-ding FANG Qin-han DING Rui 《Wuhan University Journal of Natural Sciences》 EI CAS 2005年第6期1081-1084,共4页
The rotation of skew bridges in the plane is a common phenomenon in engineering. Traditional measure is to setup pins or limiting displacement with lateral bearings, but the result is not satisfactory. In order to sol... The rotation of skew bridges in the plane is a common phenomenon in engineering. Traditional measure is to setup pins or limiting displacement with lateral bearings, but the result is not satisfactory. In order to solve this problem, the reason for the rotation in the plane is found by philosophy analysis and an idea regarding the application of slantleg frame skew bridges without abutment is brought forward in this paper. Theory and engineering practices indicate that slant-leg rigid frame bridges without abutment can restrain the rotation of skew bridges in the plane to the utmost extent because of its structural characteristics and can fundamentally solve the tough defect of skew bridges. 展开更多
关键词 slant-leg rigid frame bridges without abutment skew bridge rotation in the plane
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Dissipation function in turbulent plane Poiseuille and Couette flows subject to spanwise rotations
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作者 Zhenhua XIA Yipeng SHI +1 位作者 Qingdong CAI Jie GAI 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2019年第2期185-192,共8页
The dissipation function in turbulent plane Poiseuille flows(PPFs) and plane Couette flows(PCFs) subject to spanwise rotations is analyzed. It is found that, in the PCFs without system rotations, the mean part is cons... The dissipation function in turbulent plane Poiseuille flows(PPFs) and plane Couette flows(PCFs) subject to spanwise rotations is analyzed. It is found that, in the PCFs without system rotations, the mean part is constant while the fluctuation part follows a logarithmic law, resulting in a similar logarithmic skin friction law as PPFs.However, if the flow system rotates in the spanwise direction, no obvious dependence on the rotation number can be evaluated. In the PPFs with rotations, the dissipation function shows an increase with the rotation number, while in the PCFs with rotations,when the rotation number increases, the dissipation function first decreases and then increases. 展开更多
关键词 dissipation function spanwise rotation plane Poiseuille flow(PPF) plane Couette flow(PCF)
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Effect of Rotation, Magnetic Field and Initial Stresses on Propagation of Plane Waves in Transversely Isotropic Dissipative Half Space
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作者 Sushant Shekhar Imtiyaz A. Parvez 《Applied Mathematics》 2013年第8期107-113,共7页
The problem regarding the reflection of plane waves in a transversely isotropic dissipative medium is considered, in which we are studying about the reflection of incidence waves in initially stressed dissipative half... The problem regarding the reflection of plane waves in a transversely isotropic dissipative medium is considered, in which we are studying about the reflection of incidence waves in initially stressed dissipative half space. After solving the governing equations, we find the two complex quasi-P (qP) and quasi-SV (qSV) waves. The occurrence of reflected waves is studied to calculate the reflection coefficient and the energy partition of incidence wave at the plane boundary of the dissipative medium. Numerical example is considered for the reflection coefficient and the partition of incident energy, in which we study about the effect of rotation, initial stresses and magnetic field. 展开更多
关键词 Magnetic Field Initial Stress rotation REFLECTION of plane WAVES REFLECTION COEFFICIENTS Energy Ratios
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Plane Vibrations in a Transversely Isotropic Infinite Hollow Cylinder Under Effect of the Rotation and Magnetic Field
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作者 F.S.Bayones A.M.Abd-Alla 《Computer Modeling in Engineering & Sciences》 SCIE EI 2017年第2期151-170,共20页
The aim of this paper is to study the effects of rotation and magnetic field on the plane vibrations in a transversely isotropic material of an infinite hollow cylinder.The natural frequency of the plane vibrations in... The aim of this paper is to study the effects of rotation and magnetic field on the plane vibrations in a transversely isotropic material of an infinite hollow cylinder.The natural frequency of the plane vibrations in the case of harmonic vibrations has been obtained.The natural frequencies are calculated numerically and the effects of rotation and magnetic field are discussed.The numerical results obtained have been illustrated graphically to understand the behavior of frequency equation with different values of frequencyωunder effects the rotation and magnetic field.Comparison was made with the results obtained in the presence and absence of the rotation and magnetic field.The results indicate that the effect of rotation and magnetic field are very pronounced. 展开更多
关键词 plane transversely ISOTROPIC rotating magnetic field HOMOGENEOUS transversely ISOTROPIC Natural frequencies
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Discussion on rotational tectonic stress field and the genesis of circum-Ordos landmass fault system 被引量:4
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作者 XIE Xin-sheng(谢新生) 《Acta Seismologica Sinica(English Edition)》 CSCD 2004年第4期464-472,共9页
When the resultant of applied forces does not pass through the center of an active landmass, the landmass will rotate, giving rise to a rotational tectonic stress field. The motion of a fault along the principal stres... When the resultant of applied forces does not pass through the center of an active landmass, the landmass will rotate, giving rise to a rotational tectonic stress field. The motion of a fault along the principal stress plane is de-termined by the mechanic features of the plane. Tensile fractures occur on the faults in the direction of the principal extensional stress plane, and fault-depression basins will be formed under a long-term action. Thrusting and over-thrusting occur on faults in the direction of the principal compressional stress plane, or folds may be formed as a result. Information on geology shows that the North China landmass, which remained stable and intact for a long time, became disjointed in the Eogene period. In the course of disjunction, anticlockwise rotation took place in the Shanxi-Hebei-Shaanxi (Jin-Ji-Shan) landmass, giving rise to the fault-depression system in its periphery. In the Pliocene epoch the landmass lost stability and its eastern boundary moved westward. As a result, the Shanxi gra-ben system appeared and Ordos landmass was formed. Structural and mechanic features of the main faults around Jin-Ji-Shan landmass can be explained with principal stress plane of a rotational tectonic stress field. 展开更多
关键词 landmass rotation rotational structure principal stress plane Jin-Ji-Shan landmass ORDOS
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Reflection of Plane Waves from Free Surface of an Initially Stressed Rotating Orthotropic Dissipative Solid Half-Space 被引量:1
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作者 Baljeet Singh Jyoti Arora 《Engineering(科研)》 2012年第3期170-175,共6页
The governing equations of an initially stressed rotating orthotropic dissipative medium are solved analytically to obtain the velocity equation which indicates the existence of two quasi-planar waves. The appropriate... The governing equations of an initially stressed rotating orthotropic dissipative medium are solved analytically to obtain the velocity equation which indicates the existence of two quasi-planar waves. The appropriate particular solutions in the half-space satisfy the required boundary conditions at the stress-free surface to obtain the expressions of the reflec-tion coefficients of the reflected quasi-P (qP) and reflected quasi-SV (qSV) waves in closed form for the incidence of qP and qSV waves. A particular model is chosen for numerical computation of these reflection coefficients for a certain range of the angle of incidence. The numerical values of these reflection coefficients are shown graphically against the angle of incidence for different values of initial stress parameter and rotation parameter. The impact of initial stress and rotation parameters on the reflection coefficients is observed significantly. 展开更多
关键词 ORTHOTROPIC DISSIPATIVE Medium Initial Stress rotation plane WAVES REFLECTION REFLECTION COEFFICIENTS
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Do Femoral Neck and Stem Anteversion Affect Final Femur Rotation and Pelvic Positioning after Total Hip Arthroplasty?
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作者 Norio Imai Tomoyuki Ito +4 位作者 Yasuhito Takahashi Yoji Horigome Ken Suda Dai Miyasaka Naoto Endo 《Open Journal of Orthopedics》 2013年第3期183-188,共6页
In this study, we have investigated the rotation of the pre-operative and post-operative femur, and stem anteversion to prevent impingement and dislocation. We studied 126 patients who had undergone primary total hip ... In this study, we have investigated the rotation of the pre-operative and post-operative femur, and stem anteversion to prevent impingement and dislocation. We studied 126 patients who had undergone primary total hip arthroplasty (THA) for the treatment of osteoarthritis. We compared preoperative tilt of anterior pelvic plane (APP), posterior condylar axis of the femur (PCA) relative to APP (APP-PCA) with those of postoperative ones in supine position. There was a moderate correlation between the preand post-operative APP-PCA values (r = 0.71). The postoperative APP-PCA decreased by approximately 6°. However, there was poor correlation between the stem anteversion and the postoperative APP-PCA (r = -0.27). A greater reduction in APP-PCA was observed among patients who exhibited greater external rotation of femur compared to those who showed less external rotation in supine position before THA. We also observed that the post-operative rotation of the femur was dependent on the pre-operative rotation of the femur while it was independent of the stem anteversion. 展开更多
关键词 ANTERIOR PELVIC plane Posterior Condylar Axis rotation Total Hip ARTHROPLASTY
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APPLICATION OF VECTOR ROTATING METHOD IN GRINDING INVOLUTE WORM WITH PLANE ENVELOPE METHOD 被引量:1
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作者 Shang Xiangdong Fu Jingshun College of Mechanical Engineering,Shenyang Polytechnic University Duan Zhenyun Dalian University of Technology 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 1999年第4期317-320,共4页
The grinding principle of plane envelope is demonstrated with the medium rack theory.The basic and general fixing patterns of grinding involute worms with plane envelope method are uniformed.The vector rotating method... The grinding principle of plane envelope is demonstrated with the medium rack theory.The basic and general fixing patterns of grinding involute worms with plane envelope method are uniformed.The vector rotating method is originally applied to calculate precisely the grinding wheel fixing angles γ h and γ n under the general fixing pattern.It is proved with experiments that the method is feasible. 展开更多
关键词 Medium rack Vector rotating plane envelope Worm grinding
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一种利用平面绕轴转动进行轴标定的方法
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作者 徐杰 李振亮 梁吉祥 《计算机应用与软件》 北大核心 2024年第5期107-112,共6页
提出一种基于平面绕轴转动计算转轴直线方程的方法。分别讨论了多平面方程组的秩为3和秩为2两种情况的解法。除了秩为1的情形外,该方法适用于大部分的转轴标定情况。实验表明转轴标定误差与平面方程系数的误差大小成正比,标定精度优于... 提出一种基于平面绕轴转动计算转轴直线方程的方法。分别讨论了多平面方程组的秩为3和秩为2两种情况的解法。除了秩为1的情形外,该方法适用于大部分的转轴标定情况。实验表明转轴标定误差与平面方程系数的误差大小成正比,标定精度优于基于空间点绕轴转动方法的标定精度。 展开更多
关键词 转轴 标定 平面转动
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基于自转一阶非连续式微球双平盘研磨的运动学分析与实验研究
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作者 吕迅 李媛媛 +3 位作者 欧阳洋 焦荣辉 王君 杨雨泽 《表面技术》 EI CAS CSCD 北大核心 2024年第8期133-144,共12页
目的分析不同研磨压力、下研磨盘转速、保持架偏心距和固着磨料粒度对微球精度的影响,确定自转一阶非连续式双平面研磨方式在加工GCr15轴承钢球时的最优研磨参数,提高微球的形状精度和表面质量。方法首先对自转一阶非连续式双平盘研磨... 目的分析不同研磨压力、下研磨盘转速、保持架偏心距和固着磨料粒度对微球精度的影响,确定自转一阶非连续式双平面研磨方式在加工GCr15轴承钢球时的最优研磨参数,提高微球的形状精度和表面质量。方法首先对自转一阶非连续式双平盘研磨方式微球进行运动学分析,引入滑动比衡量微球在不同摩擦因数区域的运动状态,建立自转一阶非连续式双平盘研磨方式下的微球轨迹仿真模型,利用MATLAB对研磨轨迹进行仿真,分析滑动比对研磨轨迹包络情况的影响。搭建自转一阶非连续式微球双平面研磨方式的实验平台,采用单因素实验分析主要研磨参数对微球精度的影响,得到考虑圆度和表面粗糙度的最优参数组合。结果实验结果表明,在研磨压力为0.10 N、下研磨盘转速为20 r/min、保持架偏心距为90 mm、固着磨料粒度为3000目时,微球圆度由研磨前的1.14μm下降至0.25μm,表面粗糙度由0.1291μm下降至0.0290μm。结论在自转一阶非连续式微球双平盘研磨方式下,微球自转轴方位角发生突变,使研磨轨迹全覆盖在球坯表面。随着研磨压力、下研磨盘转速、保持架偏心距的增大,微球圆度和表面粗糙度呈现先降低后升高的趋势。随着研磨压力与下研磨盘转速的增大,材料去除速率不断增大,随着保持架偏心距的增大,材料去除速率降低。随着固着磨料粒度的减小,微球的圆度和表面粗糙度降低,材料去除速率降低。 展开更多
关键词 自转一阶非连续 双平盘研磨 微球 运动学分析 研磨轨迹 研磨参数
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应用旋转皮瓣修复鼻唇部皮肤缺损的手术技巧和术式探讨
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作者 郭建滨 郑敏 吕燕 《中国美容医学》 CAS 2024年第1期32-36,共5页
目的:探讨应用旋转皮瓣修复鼻唇部皮肤缺损的手术技巧和术式。方法:选择2020年4月-2022年4月笔者医院门诊部收治的鼻唇部皮肤缺损患者90例,根据患者治疗意愿分为旋转皮瓣组、推进皮瓣组和“Z”形皮瓣组三组,各30例,分别给予旋转皮瓣、... 目的:探讨应用旋转皮瓣修复鼻唇部皮肤缺损的手术技巧和术式。方法:选择2020年4月-2022年4月笔者医院门诊部收治的鼻唇部皮肤缺损患者90例,根据患者治疗意愿分为旋转皮瓣组、推进皮瓣组和“Z”形皮瓣组三组,各30例,分别给予旋转皮瓣、推进皮瓣和“Z”形皮瓣修复。分析各组患者皮瓣成活情况、瘢痕情况、疗效及外形、疼痛总分与疼痛强度、生活质量和心理状态以及并发症发生率和满意度。结果:三组患者皮瓣成活情况、瘢痕情况、疗效及外形、疼痛总分与疼痛强度、生活质量和心理状态以及并发症发生率和满意度比较,差异有统计学意义(P<0.05)。旋转皮瓣组患者总体满意度为100.00%,而推进皮瓣组和“Z”形皮瓣组患者的总体满意度仅为86.67%和80.00%;且旋转皮瓣组患者皮瓣成活率、疗效及外形得分均较其他组高(均P<0.05),而疼痛强度评分和并发症发生率较其他组低(P<0.05),患者鼻唇部皮肤缺损得到了较好的治愈。结论:修复鼻唇部皮肤缺损手术方式繁多且各有优缺点,通过正确地选用术式并强调手术中操作技巧可以取得更加理想的手术效果。旋转皮瓣修复鼻唇部皮肤缺损方面效果显著。 展开更多
关键词 旋转皮瓣 鼻平面 鼻唇部皮肤缺损 手术技巧 术式探讨
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应用两种旋转矢量法研究平面简谐波
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作者 王杰 刘芬芬 +1 位作者 周鸣宇 孙江 《高师理科学刊》 2024年第8期102-105,110,共5页
如何正确应用振动旋转矢量和空间(波动)旋转矢量研究平面简谐波的问题,是大学物理教学中的一个重点问题.在系统对比分析两种旋转矢量的基础上,从波函数和波形图两方面比较分析了两种旋转矢量在描述平面简谐波上的异同,归纳了应用两种旋... 如何正确应用振动旋转矢量和空间(波动)旋转矢量研究平面简谐波的问题,是大学物理教学中的一个重点问题.在系统对比分析两种旋转矢量的基础上,从波函数和波形图两方面比较分析了两种旋转矢量在描述平面简谐波上的异同,归纳了应用两种旋转矢量解决平面简谐波问题时应注意的问题.结果表明,应用两种旋转矢量都能较大程度地降低分析解决平面简谐波问题的难度.在应用时,应说明旋转矢量的类型和注意其特征,避免混淆出错. 展开更多
关键词 振动旋转矢量 空间(振动)旋转矢量 平面简谐波
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2×75转体桥上跨国铁铁路T构设计
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作者 吴珍瑞 《价值工程》 2024年第12期64-66,共3页
转体T构桥施工简单、工艺成熟,跨越能力强,具有对既有线运营影响小的优点,在中等跨度跨线桥桥型方案中,具有明显的优势。本文以某上跨国铁铁路高速立交桥采用的(75+75)m预应力混凝土T型钢构为研究对象,结合平面整幅转体法施工,在满足既... 转体T构桥施工简单、工艺成熟,跨越能力强,具有对既有线运营影响小的优点,在中等跨度跨线桥桥型方案中,具有明显的优势。本文以某上跨国铁铁路高速立交桥采用的(75+75)m预应力混凝土T型钢构为研究对象,结合平面整幅转体法施工,在满足既有铁路建筑限界的同时,有效地减小了线上施工对铁路既有设备及运营的影响。本文详细介绍了转体桥上、下部结构构成形式及尺寸参数,其中转体桥关键部位转体系统的设计,对未来类似跨径级别的上跨铁路转体桥设计工作提供了有价值的参考。 展开更多
关键词 公路跨线桥 T形刚构 平面转体施工 设计 结构分析
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DEVELOPMENT OF VIRTUAL INSTRUMENT IN CHARACTERISTIC ANALYSIS OF ROTATING MACHINERY BASED ON INSTANTANEOUS FREQUENCY ESTIMATION 被引量:4
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作者 YangJiongming QinShuren +1 位作者 JiZhong GuoYu 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2004年第4期490-493,共4页
Based on the recently quick-developing time-frequency analysis (TFA)technique and virtual instrument (VI) technique, a virtual instrument in characteristic analysis ofrotating machinery is researched and developed suc... Based on the recently quick-developing time-frequency analysis (TFA)technique and virtual instrument (VI) technique, a virtual instrument in characteristic analysis ofrotating machinery is researched and developed successfully. By utilizing instantaneous frequencyestimation (IFE) theoretics of TFA technique, and based on IFE of peak searching on thetime-frequency spectrum, order analysis (OA) functions is put forward and implemented, such as orderspectrum, order spectrum matrix, order tracking, order tracking filtering, and order componentextraction, etc. Unlike the home and abroad existing popular characteristic analyzers, which needkey phasing devices such as shaft encoder, phase-locked loop (PLL), phase-locked multiple frequency,tachometer, etc, to implement constant angle sampling directly or indirectly, whereas thisinstrument only uses the vibration signal of rotating machinery to carry out OA. This instrumentmakes up the shortage of these traditional instruments in analyzing the non-stationary signal ofrun-up and run-down process of rotating machinery. Therefore, it is a great breakthrough for theexisting order analyzers. 展开更多
关键词 rotating machinery time-frequency analysis Instantaneous frequency Orderanalysis Virtual instrument
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Numerical Analysis and Experimental Validation of a Submerged Inlet on the Plane Surface 被引量:6
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作者 孙姝 郭荣伟 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2005年第3期199-205,共7页
In order to get a deep insight of a submerged inlet on the plane surface, the integrated flow field of the inlet and fuselage has been numerically studied. The investigation is mainly focused on the formation of the t... In order to get a deep insight of a submerged inlet on the plane surface, the integrated flow field of the inlet and fuselage has been numerically studied. The investigation is mainly focused on the formation of the total pressure distribution at the exit of the inlet, the structure of the inner flow and the effects of the boundary layer along the fuselage on the performance of the inlet. Moreover, in comparison with the experimental data at different angles of attack, yaws and mass flow ratios, the reliabilities of the computational fluid dynamics(CFD) studied are verified. Results indicate: (1) the CFD results agree well with the experiment results and the relative errors of the total pressure coefficient is less than 1% ; (2) at the inlet's exit, the contour of total pressure obtained by CFD is similar to the experiment result except the contour in the low total pressure zone in CFD is slightly larger; (3) the secondary flow at the cross section behave as two counter-rotating vortices. Along the flow direction, the fields influenced by the vortex pair transport downstream and expand to the whole section at the exit; (4) the total pressure loss at the exit of the submerged inlet can be divided into external loss and internal loss. Usually, the external loss is greater than the internal loss, and both decrease with the augment of the Mach number at the exit. In addition, when the angle of attack ranges from -2° to 8°, the total pressure coefficient ascends gradually, due to the reduction of the external loss caused by the less boundary layer flow captured and the invisible change of the internal loss. 展开更多
关键词 submerged inlet on the plane surface CFD boundary layer counter-rotating vortices total pressure coefficient
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相控阵测控技术(一):相控阵角跟踪概论 被引量:3
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作者 刘嘉兴 《电讯技术》 北大核心 2023年第8期1125-1132,共8页
相控阵同时多波束对多目标的高精度连续闭环角跟踪,是相控阵技术中的一个新的重要领域。针对此,提出用递归累加进行相位控制并构成一个积分环节,以此为基础构建成基本的一阶角跟踪环路,在环路中可再增加积分环节的个数构建成高阶的自动... 相控阵同时多波束对多目标的高精度连续闭环角跟踪,是相控阵技术中的一个新的重要领域。针对此,提出用递归累加进行相位控制并构成一个积分环节,以此为基础构建成基本的一阶角跟踪环路,在环路中可再增加积分环节的个数构建成高阶的自动控制系统,从而实现高精度的连续角跟踪。给出了系统框图,推导出了常用的二阶环的闭环传递函数表达式,它与锁相环的闭环传递函数类似,可以应用锁相环技术的很多有关成果。还介绍了投影面转动法、空窗滑动法等相控阵角跟踪方法,尽管它们的跟踪方案不同但都具有相同的闭环传递函数模型。 展开更多
关键词 相控阵测控 连续角跟踪 递归累加环 闭环传递函数 投影面转动法 空窗滑动法
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全附体潜艇旋臂水池试验及单平面受力研究
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作者 赵博文 贠莹莹 +2 位作者 孙济源 杨志国 黄滨 《浙江大学学报(工学版)》 EI CAS CSCD 北大核心 2023年第4期773-783,共11页
为了研究水下航行器在定常回转中的水动力特性及受力运动规律,以潜艇标模SUBOFF AFF-8为研究对象,在浙江大学旋臂水池中进行潜艇操纵性回转试验.介绍潜艇旋臂水池试验的测试技术,包括模型安装、数据测量及六分力天平的标定与校核.获取... 为了研究水下航行器在定常回转中的水动力特性及受力运动规律,以潜艇标模SUBOFF AFF-8为研究对象,在浙江大学旋臂水池中进行潜艇操纵性回转试验.介绍潜艇旋臂水池试验的测试技术,包括模型安装、数据测量及六分力天平的标定与校核.获取水平面和垂直面的旋转导数,与泰勒水池的实验值形成对比.结果表明,浙江大学水池与泰勒水池相比,误差小于10%,证明浙江大学旋臂水池对潜艇操纵性试验的测量具有一定的可靠性.在水平面运动中,纵向力和横向力随漂角的变化曲线以0°漂角为分界点左右对称,横摇力矩和偏航力矩随漂角的增大而增大,垂向力和俯仰力矩随漂角的变化近似呈抛物线分布.垂直面运动时,上浮和下潜运动的力和力矩呈对称分布.角速度越大,纵向力越大,在较高的角速度下,不同攻角下的力差值较大. 展开更多
关键词 旋臂试验 操纵性 全附体潜艇 单平面受力
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上跨庐山站立交工程转体斜拉桥总体设计 被引量:1
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作者 周继 《世界桥梁》 北大核心 2023年第2期21-27,共7页
九江市新建快速路上跨庐山站立交工程跨越昌九城际、京九铁路、武九铁路等12股铁路线,经方案比选,主桥采用(99+250+116) m高低塔中央索面混凝土转体斜拉桥。低塔侧采用半飘浮体系,高塔侧采用塔梁墩固结体系。主梁采用大悬臂单箱三室混... 九江市新建快速路上跨庐山站立交工程跨越昌九城际、京九铁路、武九铁路等12股铁路线,经方案比选,主桥采用(99+250+116) m高低塔中央索面混凝土转体斜拉桥。低塔侧采用半飘浮体系,高塔侧采用塔梁墩固结体系。主梁采用大悬臂单箱三室混凝土箱梁,梁高3.5 m,梁宽42 m,桥面两侧设置2道HA级混凝土防撞护栏。桥塔采用独柱形钢筋混凝土结构,高、低塔桥面以上塔高分别为65 m、57 m,塔柱采用矩形空心截面,低塔侧下塔柱设置牛腿式下横梁,基础采用?3.0 m的钻孔桩。斜拉索采用智能型平行钢绞线,外层包HDPE护套,塔端张拉,梁端锚固。转动体系采用球铰转动系统,转体长度分别为(132+112.5) m、(95.5+114) m,转体重量分别约为4.76万吨、4.14万吨。 展开更多
关键词 斜拉桥 跨铁路 高低塔 中央索面 塔梁墩固结 转体施工 桥梁设计
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室内场景下基于曼哈顿约束的多重特征视觉SLAM方法 被引量:3
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作者 孙新柱 龚光强 +2 位作者 陈孟元 程浩 郭行荣 《中国惯性技术学报》 EI CSCD 北大核心 2023年第9期890-899,共10页
针对基于点特征的视觉同步定位与地图构建(SLAM)在室内低纹理环境出现定位精度差甚至失效的问题,提出一种基于曼哈顿约束的点线面多重特征视觉SLAM方法。为克服传统面特征提取算法检测精度差的问题,使用改进的PlaneRecNet网络进行更准... 针对基于点特征的视觉同步定位与地图构建(SLAM)在室内低纹理环境出现定位精度差甚至失效的问题,提出一种基于曼哈顿约束的点线面多重特征视觉SLAM方法。为克服传统面特征提取算法检测精度差的问题,使用改进的PlaneRecNet网络进行更准确的面特征提取。针对单纯利用曼哈顿假设进行位姿估计的应用场景受限问题,利用平面间的正交关系判断曼哈顿假设条件。在非曼哈顿场景直接跟踪点、线特征估计六自由度位姿;对于曼哈顿场景,采用方向引导的方法筛选主平面,比较和跟踪平面结构的正交性进行三自由度旋转估计,降低旋转累积误差带来的漂移。在公开ICL-NUIM与TUM数据集上的实验结果表明:改进的面分割网络较PlaneRecNet和PlaneRCNN的精度分别提升5.47%和11.89%;平均绝对轨迹误差比ORB-SLAM3减少了39%,表现出了更优越的准确性和鲁棒性。 展开更多
关键词 视觉同步定位与地图构建 曼哈顿约束 面特征 旋转估计
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