New insights of the Cenozoic Rotational Deformation of Crustal Blocks on the Southeastern Margin of the Tibetan Plateau and its Tectonic Implications

Objective The lateral extrusion of southeastern edge of the crustal materials around the Tibetan Plateau since the Oligocene is believed to be one of the main inducements of-1300 km latitudinal crustal convergence in the Tibetan Plateau, since the collision of India and Eurasia in the Paleogene. Two end-member models were used to describe the process of lateral extrusion of crustal material on the southeastern edge of the Tibetan Plateau. The ＂tectonic escape＂ model suggests the Indochina Block, Chuandian Fragment and Shan-Thai Block have experienced lateral extrusion along strike-slip fault systems, and the ＂crustal flow＂ model suggests that the upper crust has undergone southeastward escape in the form of ductile deformation, driven by viscous lower crustal flow channels. In addition, the GPS observations surrounding the Tibetan Plateau indicate that crustal materials currently experience clockwise rotation around the Eastern Himalaya syntaxis. This work conducted paleomagnetic studies in the Cretaceous and Paleogene red-beds along the southeastern margin of Tibetan Plateau,

Improving Local Temperature Rise in Rotational Incremental Sheet Forming Process by Modifying Forming Parameters Using Response Surface Method

In rotational incremental sheet forming( RISF) process,the friction heating of rotational tool could lead to local temperature rise of the sheet and cause the improvement of sheet's formability.Lightweight metal,such as magnesium alloy,could be deformed by RISF without additional heating. The objective of this study is to investigate the effects of forming parameters,namely,tool rotational speed,feed-rate,step size and wall angle,on the local temperature rise. Using response surface methodology and central composite design( CCD) experimental design,the significance,sequence of parameters and regression models would be analyzed with AZ31 B as the experimental material,and 3D response surface plots would be shown. Combined with actual processing conditions,the measures to improve the local temperature rise by modifying each parameter would be discussed in the end. The results showed that hierarchy of the parameters with respect to the significance of their effects on the local temperature at the side wall was: feed-rate,step size,and rotational speed,while at the bottom it was: feed-rate,step size,wall angle, and rotational speed, and no significant interaction appeared. It was found that the most significant parameter was not rotational speed,but feed-rate,followed by step size,for both test positions. In addition, the local temperature would increase by elevating step size,wall angle,rotating rate,and bringing down of feed-rate.

Dynamic analysis on generalized linear elastic body subjected to large scale rigid rotations

The dynamic analysis of a generalized linear elastic body undergoing large rigid rotations is investigated. The generalized linear elastic body is described in kine- matics through translational and rotational deformations, and a modified constitutive relation for the rotational deformation is proposed between the couple stress and the curvature tensor. Thus, the balance equations of momentum and moment are used for the motion equations of the body. The floating frame of reference formulation is applied to the elastic body that conducts rotations about a fixed axis. The motion-deformation coupled model is developed in which three types of inertia forces along with their incre- ments are elucidated. The finite element governing equations for the dynamic analysis of the elastic body under large rotations are subsequently formulated with the aid of the constrained variational principle. A penalty parameter is introduced, and the rotational angles at element nodes are treated as independent variables to meet the requirement of C1 continuity. The elastic body is discretized through the isoparametric element with 8 nodes and 48 degrees-of-freedom. As an example with an application of the motion- deformation coupled model, the dynamic analysis on a rotating cantilever with two spatial layouts relative to the rotational axis is numerically implemented. Dynamic frequencies of the rotating cantilever are presented at prescribed constant spin velocities. The maximal rigid rotational velocity is extended for ensuring the applicability of the linear model. A complete set of dynamical response of the rotating cantilever in the case of spin-up maneuver is examined, it is shown that, under the ultimate rigid rotational velocities less than the maximal rigid rotational velocity, the stress strength may exceed the material strength tolerance even though the displacement and rotational angle responses are both convergent. The influence of the cantilever layouts on their responses and the multiple displacement trajectories observed in the floating frame is simultaneously investigated. The motion-deformation coupled model is surely expected to be applicable for a broad range of practical applications.

Real-time tracking of deformable objects based on MOK algorithm

The traditional oriented FAST and rotated BRIEF（ORB） algorithm has problems of instability and repetition of keypoints and it does not possess scale invariance. In order to deal with these drawbacks, a modified ORB（MORB） algorithm is proposed. In order to improve the precision of matching and tracking, this paper puts forward an MOK algorithm that fuses MORB and Kanade-Lucas-Tomasi（KLT）. By using Kalman, the object＇s state in the next frame is predicted in order to reduce the size of search window and improve the real-time performance of object tracking. The experimental results show that the MOK algorithm can accurately track objects with deformation or with background clutters, exhibiting higher robustness and accuracy on diverse datasets. Also, the MOK algorithm has a good real-time performance with the average frame rate reaching 90.8 fps.

ON SEVERAL NEW METHODS TO POLAR DECOMPOSITION COMPUTATION

In this paper, the polar decomposition of a deformation gradient tensor is analyzed in detail. The four new methods for polar decompositioncomputation are given: (1) the iterated method, (2) the principal invariant's method, (3) the principal rotation axis' s method, (4) the coordinate transformation's method. The iterated method makes it possible to establish the nonlinear finite element method based on polar decomposition. Furthermore, the material time derivatives of the stretch tensor and the rotation tensor are obtained by explicit and simple expressions.

Discussion on the relationship between the Yanshanian Movement and cratonic destruction in North China

The relationship between the Yanshanian Movement, destruction of the North China Craton(NCC), and subduction of the western Pacific plate is crucial to reconstructing the middle-late Mesozoic tectonic evolution of the eastern Asian continent and margin. The Yanshanian Movement was a globally important change in crustal tectonics during the Middle-Late Jurassic.Previous research has systematically studied the formation and evolution of the Yanshanian Movement, focusing on the timing and location of tectonic movements, and the sedimentary and volcanic strata. However, the question of whether the tectonic activity occurred globally, and the characteristics of the Yanshanian Movement remain debated. The main argument is that if a tectonic movement can only be characterized by a regional or local disconformity, and if the tectonic movement occurred in an intracontinental setting, with extensive deformation but with no disconformity despite volcanic eruptions and magmatic intrusions, accompanied by changes in crustal structure and composition, should it be defined as a tectonic event or process? This question requires further analysis. The main aim of this study is to distinguish whether the Yanshanian Movement is a local feature of the eastern Asian continent, or a global tectonic event related to subduction of the Pacific Plate. In this paper, based on previous research, we discuss the spatial and temporal evolution of the Yanshanian Movement, the controlling tectonic mechanisms, and its relationship to the reactivation and destruction of the NCC and the subduction of the western Paleo-Pacific slab.We emphasize that the Yanshanian Movement in the Middle-Late Jurassic is distinct from the lithospheric thinning responsible for Early Cretaceous extension and magmatism related to the destruction of the NCC. The various tectonic stages were constrained by different dynamics and tectonic settings, or by different tectonic events and processes. Therefore, it is possible that the deformation and reactivation of the NCC contributed to its destruction, in addition to lithospheric thinning. Finally, we discuss whether the Yanshanian Movement was associated with the destruction of the NCC.

Projected total energy surface description for axial shape asymmetry in ^(172)W

The projected total energy surface(PTES)approach has been developed based on the triaxial projected shell model(TPSM)hybridized with the macroscopic–microscopic method.The total energy of an atomic nucleus is decomposed into macroscopic,microscopic and rotational terms.The macroscopic and microscopic components are described with the liquid drop model and Strutinsky method,respectively,and the rotational energy is given by the TPSM,the term beyond the mean field.To test theory,the PTES calculations have been carried out for the yrast states of the well deformed rare earth nucleus172W,and the theoretical results are in good agreement with the experimental data.By using the equilibrium quardrupole deformations(ε2andγ)determined by the PTES,the calculation of the transition quardrupole moment(Qt)in function of spin also reproduces the experimental data.A comparison between the PTES and TRS methods has been made for theoretical and application uses.

Systematic dependence of SFE＊B(E2)↑ and ROTE＊B(E2)↑on N_pN_n in the framework of shape fluctuation model

A systematic dependence of shape fluctuation energy product SFE ＊ B（E2）↑ and rotational energy product ROTE ＊ B（E2）↑ on the valence nucleon product Np Nn is carried out in the Z = 50-82,N = 82-126 major shell space.For the shape transitional nuclei,the product SFE＊B（E2）↑ drops to zero and becomes negative,indicating direct dependence on N_pN_n.A relative rise,on the other hand,is observed in the product ROTE＊B（E2） ↑plotted against N_pN_n for all the nuclei in Z = 50-82 and N = 82-126.In the N 〉 104 region,large positive values of the product SFE ＊ B（E2） ↑ are observed for the Pt nucleus,which indicates sphericity.A systematic study of the product SFE ＊ B（E2）↑ and ROTE ＊ B（E2） ↑ with atomic number Z is also discussed.The products SFE ＊ B（E2） ↑and ROTE ＊ B（E2） ↑ vary sharply with Z for the N = 88 isotones.We discuss here for the first time the correlation between SFE ＊ B（E2） ↑ and ROTE ＊ B（E2） ↑ with valence nucleon product N_pN_n.