Influence of the layered Moon and Earth’s orientation on lunar rotation

One of the most efficient ways to probe the lunar inner structure at present is through the study of its rotation.Range and range rate(Doppler) data between the Chang’E-3 lander and station on the Earth were collected from the beginning of the Chang’E-3 lunar mission in 2013.These observation data,taken together with the existing lunar laser ranging data,provide a new approach to extend research on the Earth-Moon system.The high precision of current observation data imposes exacting demands,making it necessary to include previously neglected factors.In this paper,motivated by progress of the Chinese lunar exploration project and to use its data in the near future,two lunar models:a one-layer model and a two-layer model with a fluid core,were applied to the rotational equations based on our implemented algorithm of the Moon’s motion.There was a difference of about 0.5′′in φ and ψ,but 0.2′′in θ between the two models.This result confirms that stratification of the inner structure of the Moon can be inferred from rotation data.We also added precise Earth rotation parameters in our model;the results show that this factor is negligible at present,due to the limited precision of the existing data.These results will help us understand the rotational process clearly and build a more realistic Earth-Moon model when we combine Lunar Laser Ranging data with high precision radio data to fit lunar motion in the near future.

2D-HIDDEN MARKOV MODEL FEATURE EXTRACTION STRATEGY OF ROTATING MACHINERY FAULT DIAGNOSIS

A new feature extraction method based on 2D-hidden Markov model（HMM） is proposed. Meanwhile the time index and frequency index are introduced to represent the new features. The new feature extraction strategy is tested by the experimental data that collected from Bently rotor experiment system. The results show that this methodology is very effective to extract the feature of vibration signals in the rotor speed-up course and can be extended to other non-stationary signal analysis fields in the future.

Rotating Lepton Model of Pions and Kaons: Mechanics at fm Distances

The present article is a continuation of a recently published paper [1] in which we have modeled the composition and structure of neutrons and other hadrons using the Rotating Lepton Model (RLM) which is a Bohr type model employing the relativistic gravitational attraction between three ultrafast rotating neutrinos as the centripetal force. The RLM accounts for special relativity and also for the De Broglie equation of quantum mechanics. In this way this force was shown to reach the value of the Strong Force while the values of the masses of the rotating relativistic neutrinos reach those of quarks. Masses computed for twelve hadrons and bosons are in very close (~2%) agreement with the experimental values. Here we use the same RLM approach to describe the composition and structure and to compute the masses of Pions and Kaons which are important zero spin mesons. Contrary to hadrons and bosons which have been found via the RLM to comprise the heaviest neutrino eigenmass m3, in the case of mesons the intermediate neutrino mass eigenstate m2 is found to play the dominant role. This can explain why the lowest masses of mesons are generally smaller than those of hadrons and bosons. Thus in the case of Pions it is found that they comprise three rotating m2 mass eigenstate neutrinos and the computed mass of 136.6 MeV/c2 is in good agreement with the experimental value of 134.977 MeV/c2. The Kaon structure is found to consist of six m2 mass eigenstate neutrinos arranged in two parallel pion-type rotating triads. The computed Kaon mass differs less that 2% from the experimental K± and K°values of 493.677 MeV/c2 and 497.648 MeV/c2 respectively. This, in conjunction with the experimentally observed decay products of the Kaons, provides strong support for the proposed K structure.

风力机旋转叶片脉动风场建模与数值仿真

分析了风力机风场模型与普通建筑风场模型的相同点和不同点,指出叶片的转动将改变叶片上风速模拟点风速谱的能量分布,使相当部分的频率能量集中到风轮旋转频率及其倍频处。根据标准vonKarman模型和旋转采样谱模型,推导并建立了风力机叶片的脉动风速谱功率矩阵,并在此基础上,采用谐波叠加法模拟了叶片脉动风速模拟点的风速时序数据。

风力发电机旋转样本谱及疲劳寿命预测

为了考虑桨叶旋转效应,准确进行风力发电机疲劳寿命预测,提出了基于旋转样本谱的风力发电机疲劳寿命预测模型.借助Fourier变换,推导了考虑旋转效应的旋转样本谱,并与Von Karman谱(一种固定点紊流风谱)进行比较.在旋转样本谱的基础上,提出了源于Palmgren-Miner线性损伤准则的风力发电机疲劳寿命预测模型,并以1.25MW风力发电机为例进行疲劳寿命分析.结果表明,与固定点紊流风谱相比,旋转样本谱的能量分布发生了根本变化,其能量由低频向高频移动,在高频段曲线会出现多峰情况;基于旋转样本谱的疲劳寿命分析更接近实际情况,而基于Von Karman谱进行风力发电机疲劳寿命预测不够精确,且偏于不安全.

数值模拟技术的发展现状

地震波场的数值模拟技术有助于认识复杂介质中地震波传播规律 ,检验各种方法技术的使用范围与应用效果。从新方法技术、模拟效果分析和应用实例等 3方面概括了本届EAGE年会有关数值模拟技术的特点 ,由此可以看出地震波场数值模拟技术的发展现状。

点迹-曲线关联算法的旋转对称群目标分辨

基于微多普勒效应分析的弹道目标识别得到了广泛研究,然而传统的微多普勒特征提取技术大都难以解决空间群目标的分辨与识别。针对这一问题,提出了一种基于点迹-曲线关联算法的空间群目标分辨方法。在以旋转对称群目标为研究对象的前提下,建立了具有滑动散射特性的目标模型并分析推导了散射点的微动表达式,利用点迹凝聚处理抑制了一维距离像旁瓣,在此基础上,提出了点迹-曲线关联算法分离出混叠的群目标微多普勒曲线,通过各曲线的极值包络特性差异实现了旋转对称群目标分辨。实验仿真验证了本方法的正确性和可行性。

基于隐式模型表示的对称物体检测算法

针对自然界中具有旋转对称特征物体的不规则性和随机性特点,提出一种新的图像旋转目标检测算法。使用基于隐式模型表示的方法来统计图像中关键点的空间位置分布,并在此基础上对物体的旋转中心进行估计。通过中层特征对图像中视觉感兴趣的关键点进行提取,在所提取关键点的特征空间进行无监督学习,将这些关键点所在空间位置聚类为不同的旋转特征簇,进而通过各个特征簇的投票值,获得在特定半径下的中心概率映射图。使用多半径尺度的显著度检测对各个半径下得到的概率映射图进行加权叠加,获得图像全局的旋转中心概率映射图,并通过显著度检测算法获取旋转中心坐标。实验结果表明,该算法对自然图像中不规则的旋转对称物体都能够进行有效的检测,对旋转对称中心的估计也具有较高的精度。

Long-term organic and inorganic fertilizations enhanced basic soil productivity in a fluvo-aquic soil

The improvement of soil productivity depends on a rational input of water and nutrients, optimal field management, and the increase of basic soil productivity（BSP）. In this study, BSP is defined as the productive capacity of a farmland soil with its own physical and chemical properties for a specific crop season under local field management. Based on 19-yr data of the long-term agronomic experiments（1989–2008） on a fluvo-aquic soil in Zhengzhou, Henan Province, China, the decision support system for agrotechnology transfer（DSSAT ver. 4.0） crop growth model was used to simulate yields by BSP of winter wheat（Triticum aestivium L.） and summer maize（Zea mays L.） to examine the relationship between BSP and soil organic carbon（SOC） under long-term fertilization. Five treatments were included：（1） no fertilization（control）,（2） nitrogen, phosphorus and potassium fertilizers（NPK）,（3） NPK plus manure（NPKM）,（4） 1.5 times of NPKM（1.5NPKM）, and（5） NPK plus straw（NPKS）. After 19 yr of treatments, the SOC stock increased 16.7, 44.2, 69.9, and 25.2% under the NPK, NPKM, 1.5NPKM, and NPKS, respectively, compared to the initial value. Among various nutrient factors affecting contribution percentage of BSP to winter wheat and summer maize, SOC was a major affecting factor for BSP in the fluvo-aquic soil. There were significant positive correlations between SOC stock and yields by BSP of winter wheat and summer maize（P〈0.01）, and yields by BSP of winter wheat and summer maize increased 154 and 132 kg ha^（–1） when SOC stock increased 1 t C ha^（–1）. Thus, increased SOC accumulation is a crucial way for increasing BSP in fluvo-aquic soil. The manure or straw combined application with chemical fertilizers significantly enhanced BSP compared to the application of chemical fertilizers alone.

CONFORMATIONAL PROPERTIES OF STRETCHED POLYETHYLENE CHAIN

When polyethylene chains are stretched, the chains are regarded as being confined in an infinite cylinder with decreasing diameter. The conformational properties of polyethylene chains confined in an infinite cylinder are investigated by using rotational isomeric state model. Using the average conformational energy and entropy and the average length, we can determine the elastic force f, or the fraction of the energy term to the total force f(e)/f where f(e) = partial derivative /partial derivative < r > and f = partial derivative /partial derivative < r >. Comparisons with experimental data are also made. The results of these microscopic calculations are discussed in terms of the macroscopic phenomena of rubber elasticity.

Application of Novel Rotation Angular Model for 3D Mouse System Based on MEMS Accelerometers

A new scheme is proposed to model 3D angular motion of a revolving regular object with miniature, low-cost micro electro mechanical systems(MEMS) accelerometers(instead of gyroscope),which is employed in 3D mouse system.To sense 3D angular motion,the static property of MEMS accelerometer,sensitive to gravity acceleration,is exploited.With the three outputs of configured accelerometers,the proposed model is implemented to get the rotary motion of the rigid object.In order to validate the effectiveness of the proposed model,an input device is developed with the configuration of the scheme.Experimental results show that a simulated 3D cube can accurately track the rotation of the input device.The result indicates the feasibility and effectiveness of the proposed model in the 3D mouse system.

Rotational Forms of Large Eddy Simulation Turbulence Models:Modeling and Mathematical Theory

In this paper the authors present a derivation of a back-scatter rotational Large Eddy Simulation model,which is the extension of the Baldwin&Lomax model to nonequilibrium problems.The model is particularly designed to mathematically describe a fluid filling a domain with solid walls and consequently the differential operators appearing in the smoothing terms are degenerate at the boundary.After the derivation of the model,the authors prove some of the mathematical properties coming from the weighted energy estimates,which allow to prove existence and uniqueness of a class of regular weak solutions.

A Model to Predict Stall Inception of Transonic Axial Flow Fan/Compressors

A stall inception model for transonic fan/compressors is presented in this paper. It can be shown that under some assumptions the solution of unsteady flow field consists of pressure wave which propagates upstream or downstream, vortex wave and entropy wave convected with the mean flow speed. By further using the mode-matching technique and applying the conservation law and conditions reflecting the loss characteristics of a compressor in the inlet and outlet of the rotor or stator blade rows, a group of homogeneous equations can be obtained from which the stability equation can be derived. Based on the analysis of the unsteady phenomenon caused by casing treatments, the function of casing treatments has been modeled by a wall impedance condition which has been included in the stability model through the eigenvalues and the corresponding eigenfunctions of the system. Besides, the effect of shock waves in cascade channel on the stability prediction is also considered in the stall inception model. Finally, some numerical analysis and experimental investigation are also conducted with emphasis on the mutual comparison.

A high-order model of rotating stall in axial compressors with inlet distortion

In this paper,a high-order distortion model is proposed for analyzing the rotating stall inception process induced by inlet distortion in axial compressors.A distortion-generating screen in the compressor inlet is considered.By assuming a quadratic function for the local flow total pressure-drop,the existing Mansoux model is extended to include the effects of static inlet distortion,and a new high-order distortion model is derived.To illustrate the effectiveness of the distortion model,numerical simulations are performed on an eighteenth-order model.It is demonstrated that long length-scale disturbances emerge out of the distorted background flow,and further induce the onset of rotating stall in advance.In addition,the circumferential non-uniform distribution and time evolution of the axial flow are also shown to be consistent with the existing features.It is thus shown that the high-order distortion model is capable of describing the transient behavior of stall inception and will contribute further to stall detection under inlet distortion.

Investigation of cracking mechanism of the first tunnel lining during double-arch tunnel construction

To solve the engineering problem of the first tunnel lining cracking caused by the second tunnel construction of double-arch highway tunnels,a research method combining distributed optical-fibre monitoring,inversion analysis and numerical simulation that can reflect lining cracking was presented.Optical fibres were laid on opposite sides of the steel arches inside the first tunnel lining.Embedded optical-fibre monitoring was conducted continuously during the second tunnel driving.Based on the fibre-optic strain profile,the lining cracking was deduced and warned in time.The mechanical behaviour of the steel arch was investigated by the inversion analysis,which took into consideration the integrated impact of axial force and flexural moment.A two-dimensional(2D)load-structure method–based numerical model was established,considering the influence of different load distributions in each construction condition.The total strain rotating crack constitutive model was applied to reflect the cracking behaviour of concrete lining in the simulation,and the model was calibrated and verified in the laboratory.Comparative analysis between the simulated strain distribution and the distributed optical-fibre monitoring results was carried out.The deformation mode and crack distribution of the lining were analysed.The cracking mechanism was explained.Specifically,the second tunnel construction led to the loading at the top of the middle partition wall and the release of rock pressure in the first tunnel.Under these load changes,the secondary lining of the first tunnel cracked on the inner side of the top of the middle partition wall owing to tension,and compression-bending failure occurred near the right arch foot.Finally,the influence of the parameters on the lining force was analysed,and a construction optimisation scheme was proposed.

Multi-scale magnetic resonance measurements and validation of Discrete Element Model simulations

This short review describes the capabilities of magnetic resonance （MR） to image opaque single- and two-phase granular systems, such as rotating cylinders and gas-fluidized beds operated in different fluidization regimes. The unique capability of MR to not only image the solids＇ distribution （voidage） but also the velocity of the particulate phase is clearly shown. It is demonstrated that MR can provide measurements over different length and time scales. With the MR equipment used for the studies summarized here, temporal and spatial scales range from sub-millisecond to hours and from a few hundred micrometres to a few centimetres, respectively. Besides providing crucial data required for an improved understanding of the underlying physics of granular flows, multi-scale MR measurements were also used to validate numerical simulations of granular systems. It is shown that predictions of time-averaged properties, such as voidage and velocity of the particulate phase, made using the Discrete Element Model agree very well with MR measurements.

Numerical simulation of aerodynamic interactions among helicopter rotor,fuselage,engine and body of revolution

Numerical simulations of helicopter aerodynamic interactions among the main rotor,fuselage,engine inlets/outlets and slung loads of specific geometries have been conducted by very few researchers.In this work,the steady-state compressible Reynolds-averaged navier-stokes equations are solved to study the aerodynamic interactions among helicopter rotor,fuselage,engine and body of revolution in three cases,namely MI-171V5,ROBIN and UH-60A.In the first case,the downwash flow provided by the rotor of the uniform actuator disc model induces a significant deflection of the airflow velocity.The vortex-shaped distribution and evolution are discussed in detail.The engine can effectively change the overall flow field.The asymmetry of the flow field is observed by using the non-uniform actuator disc model.Qualitative analysis of ROBIN and quantitative computation of UH-60A show a consistent accuracy of the rotating reference frame model for rotor.The blade tip vortex motion of UH-60A is simulated and its radial position prediction is compared to empirical formulas.While performing flow of UH-60A in hover,both the fuselage normal force and rotor lift decrease because of the impact of the body of revolution.

Numerical study of roll motion of a 2-D floating structure in viscous flow

In the present study,an open source CFD tool,Open FOAM has been extended and applied to investigate roll motion of a 2-D rectangular barge induced by nonlinear regular waves in viscous flow.Comparisons of the present Open FOAM results with published potential-flow solutions and experimental data have indicated that the newly extended Open FOAM model is very capable of accurate modelling of wave interaction with freely rolling structures.The wave-induced roll motions,hydrodynamic forces on the barge,velocities and vorticity fields in the vicinity of the structure in the presence of waves have been investigated to reveal the real physics involved in the wave induced roll motion of a 2-D floating structure.Parametric analysis has been carried out to examine the effect of structure dimension and body draft on the roll motion.

Changing law of launching pitching angular velocity of rotating missile

In order to provide accurate launching pitching angular velocity（LPAV） for the exterior trajectory optimization design, multi-flexible body dynamics（MFBD） technology is presented to study the changing law of LPAV of the rotating missile based on spiral guideway. An MFBD virtual prototype model of the rotating missile launching system is built using multi-body dynamics modeling technology based on the built flexible body models of key components and the special force model.The built model is verified with the frequency spectrum analysis. With the flexible body contact theory and nonlinear theory of MFBD technology, the research is conducted on the influence of a series of factors on LPAV, such as launching angle change, clearance between launching canister and missile,thrust change, thrust eccentricity and mass eccentricity, etc. Through this research, some useful values of the key design parameters which are difficult to be measured in physical tests are obtained. Finally,a simplified mathematical model of the changing law of LPAV is presented through fitting virtual test results using the linear regression method and verified by physical flight tests. The research results have important significance for the exterior trajectory optimization design.

Calculation of the Neutron Direct Inelastic Scattering cross Section of ~ (238) U

In this work, Rotation model and rotation vibration coupled channel optical model (CCOM) were first used to carry out systematic calculation of neutron direct inelastic scattering cross section (DISCS) for the reaction 238 U (n,n′) with an incident energy from 0 01 MeV to 20 0 MeV . The number of coupled energy levels involved in this calculation increased to eight at the first time, namely 0 +, 2 +, 4 +, 6 +, 8 + in the ground rotation band of 238 U and 1 -, 3 -, 5 - in the octupole vibration band with K=0 -. Some physical problems, such as how to get the optical model parameters of deformed nuclei and phonon amplitudes, are discussed.