58 resultados para Rotated lattices


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An interesting interface structure between diamond film and silicon substrate has been observed. That is, according to the deformation of the diamond film crystal sturcture, a strictly 3:2 matching of the two lattices across the interface is obtained. This result clearly indicates that misfit dislocations at the interface and "epitaxial tilting" are not the only two ways to overcome the 1.5% residual misfit.

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The interaction of scopolamine and cholesterol with sphingomyelin bilayers has been investigated by FT-Raman spectroscopy in head-group region (600-1000 cm(-1)), the C-C stretching (1000-1200 cm(-1)), CH2 deformation (1400-1500 cm(-1)) and the C-H stretching (2800-3000 cm(-1)) mode regions. The results indicate that scopolamine and cholesterol do not change the conformation of O-C-C-N+ backbone in the choline group of sphingomyelin bilayers, the polar headgroup is still extending parallel to the bilayer surface and O-C-C-N+ group is still in its gauche conformer. Scopolamine and cholesterol lower the order of the interface, the interchain, CH2 crystal lattices and the lateral chain-chain packing, and increase their fluidity.

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In situ electrochemical scanning tunneling microscopy (ECSTM) and an electrochemical quartz crystal microbalance (EQCM) have been employed to follow the adsorption/desorption processes of phenanthraquinone (PQ sat. in 0.1 mol l(-1) HClO4, solution) accompanied with an electrochemical redox reaction on the Au electrode. The result shows that: (1) the reduced form PQH(2) adsorbed at the Au electrode and the desorption occurred when PQH(2) was oxidized to PQ; (2) the adsorption process initiates at steps or kinks which provide high active sites on the electrode surface for adsorption, and as the potential shifts to negative, a multilayer of PQH(2) may be formed at the Au electrode; (3) the reduced PQH(2) adsorbed preferentially in the area where the tip had been scanned continually; this result suggests that the tip induction may accelerate the adsorption of PQH(2) on the Au(111) electrode. Two kinds of possible reason have been discussed; (4) high resolution STM images show the strong substrate lattice information and the weak monolayer adsorbate lattice information simultaneously. The PQH(2) molecules pack into a not perfectly ordered condensed physisorbed layer at potentials of 0.1 and 0.2 V with an average lattice constant a = 11.5 +/- 0.4 Angstrom, b = 11.5 +/- 0.4 Angstrom, and gamma = 120 +/- 2 degrees; the molecular lattice is rotated with respect to the substrate lattice by about 23 +/- 2 degrees. (C) 1997 Elsevier Science S.A.

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The relationship between structures of complex fluorides and spectral structure of Eu(II) ion in complex fluorides (AB(m)F(n)) is investigated by means of pattern recognition methods, such as KNN, ALKNN, BAYES, LLM, SIMCA and PCA. A learning set consisting of 32 f-f transition emission host compounds and 31 d-f transition emission host compounds and a test set consisting of 27 host compounds were characterized by 12 crystal structural parameters. These parameters, i.e. features, were reduced from 12 to 6 by multiple criteria for the classification of these host compounds as f-f transition emission or d-f transition emission. A recognition rate from 79.4 to 96.8% and prediction capabilities from 85.2 to 92.6% were obtained. According to the above results, the spectral structures of Eu(II) ion in seven unknown host lattices were predicted.

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Monotopic membrane proteins are membrane proteins that interact with only one leaflet of the lipid bilayer and do not possess transmembrane spanning segments. They are endowed with important physiological functions but until now only few of them have been studied. Here we present a detailed biochemical, enzymatic and crystallographic characterization of the monotopic membrane protein sulfide:quinone oxidoreductase. Sulfide:quinone oxidoreductase is a ubiquitous enzyme involved in sulfide detoxification, in sulfide-dependent respiration and photosynthesis, and in heavy metal tolerance. It may also play a crucial role in mammals, including humans, because sulfide acts as a neurotransmitter in these organisms. We isolated and purified sulfide:quinone oxidoreductase from the native membranes of the hyperthermophilic bacterium Aquifex aeolicus. We studied the pure and solubilized enzyme by denaturing and non-denaturing polyacrylamide electrophoresis, size-exclusion chromatography, cross-linking, analytical ultracentrifugation, visible and ultraviolet spectroscopy, mass spectrometry and electron microscopy. Additionally, we report the characterization of its enzymatic activity before and after crystallization. Finally, we discuss the crystallization of sulfide:quinone oxidoreductase in respect to its membrane topology and we propose a classification of monotopic membrane protein crystal lattices. Our data support and complement an earlier description of the three-dimensional structure of A. aeolicus sulfide:quinone oxidoreductase (M. Marcia, U. Ermler, G. Peng, H. Michel, Proc Natl Acad Sci USA, 106 (2009) 9625-9630) and may serve as a reference for further studies on monotopic membrane proteins. (C) 2010 Elsevier B.V. All rights reserved.

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[1] The evolution of freshwater plumes and the associated salinity fronts in the northern Bay of Bengal ( henceforth the bay) is studied using rotated empirical orthogonal function (REOF) analysis and extended associate pattern analysis (EAPA). The results show that sea surface salinity distribution is featured by eastern-bay and western-bay plumes in the northern bay during different seasons. The western-bay plume begins in early July, peaks in late August, and then turns into a bay-shaped plume with the two plumes in either side of the bay, which peaks in late October. The southward extension of the western-bay plume can be explained by the southwestward geostrophic flow associated with the cyclonic gyre in the northern bay, which counters the northeastward Ekman drift driven by wind stress. The offshore expansion of the western-bay plume is induced by the offshore Ekman drift which also produces a salinity front near the east coast of India. The bay-shaped plume appears when the cyclonic gyre shifts westward and a weak anticyclonic gyre occupies the northeastern bay. As the season advances, the western part of the bay-shaped plume decays while the eastern part persists until the following June, which is believed to be associated with the anticyclonic gyre in the northern bay. The evolution of the plumes except the eastern part of the bay-shaped plume in fall can be partly explained by the seasonal variation of mass transport associated with the Sverdrup balance. The fact that the western-bay (eastern-bay) plume appears when surface freshwater flux in the northeastern bay increases ( decreases) dramatically suggests that the plumes are not produced directly by surface freshwater flux. River discharge seems to be the freshwater source for the plumes and has little to do with the evolution of the plumes.

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介绍了应用前苏联Fizoptika公司生产的 94 1 3AM光纤陀螺传感器 ,利用单片机最小系统开发了角速度测量和旋转角度测量仪 ,可测量旋转物体的角度和角速度 .给出了光纤陀螺仪的硬件组成、软件设计思想及标定方法

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This dissertation presents a series of irregular-grid based numerical technique for modeling seismic wave propagation in heterogeneous media. The study involves the generation of the irregular numerical mesh corresponding to the irregular grid scheme, the discretized version of motion equations under the unstructured mesh, and irregular-grid absorbing boundary conditions. The resulting numerical technique has been used in generating the synthetic data sets on the realistic complex geologic models that can examine the migration schemes. The motion equation discretization and modeling are based on Grid Method. The key idea is to use the integral equilibrium principle to replace the operator at each grid in Finite Difference scheme and variational formulation in Finite Element Method. The irregular grids of complex geologic model is generated by the Paving Method, which allow varying grid spacing according to meshing constraints. The grids have great quality at domain boundaries and contain equal quantities of nodes at interfaces, which avoids the interpolation of parameters and variables. The irregular grid absorbing boundary conditions is developed by extending the Perfectly Matched Layer method to the rotated local coordinates. The splitted PML equations of the first-order system is derived by using integral equilibrium principle. The proposed scheme can build PML boundary of arbitrary geometry in the computational domain, avoiding the special treatment at corners in a standard PML method and saving considerable memory and computation cost. The numerical implementation demonstrates the desired qualities of irregular grid based modeling technique. In particular, (1) smaller memory requirements and computational time are needed by changing the grid spacing according to local velocity; (2) Arbitrary surfaces and interface topographies are described accurately, thus removing the artificial reflection resulting from the stair approximation of the curved or dipping interfaces; (3) computational domain is significantly reduced by flexibly building the curved artificial boundaries using the irregular-grid absorbing boundary conditions. The proposed irregular grid approach is apply to reverse time migration as the extrapolation algorithm. It can discretize the smoothed velocity model by irregular grid of variable scale, which contributes to reduce the computation cost. The topography. It can also handle data set of arbitrary topography and no field correction is needed.

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Eastern Himalayan Syntaxis (EHS) and its surroundings (eastern margin of Tibet) is one of the most complicated tectonic areas in the world. As the exhaust opening of the balanced materials of the Tibetan Plateau during the collision of Indan and Eurasian plates, the deep structure beneath EHS surrounding region is referred to as the key to the study of the dynamics of the plateau. EHS3D project, sponsored by NSFC, has been proposed to explore the deep electric features of the area. During the first stage of EHS3D(2006-2008), MT+LMT measurements have been conducted along two lines from Chayu to Qingshuihe (EHS3D-3) and Chayu to Ruoergai (EHS3D-2). This paper will discuss the MT models of EHS3D-3 line. By the data procrssing, including distortion analysis, Robust estimation and strike decomposition, rotated apparent resitivities and phases have been obtained for each station. Then conventional 2-D inversion algorithms (NLCG and RRI) were employed to produce 2-D models. The final preferred 2-D model suggests that the upper crust consists of resistive blocks while in mid-lower crust there are two extensive conductive bodies beneath Lhasa block and Qiangtang terrain respectively. Jinshajiang suture is a gradient belt and Bangong-Nujiang suture appear a conductive belt dipping to the north. . We concluded that the formation of the two conductive bodies attributed to the partial melt and fluids in the lower crust. The regional electric strike derived from decomposition analysis indicates that the crust and upper mantle move in different manners. The upper crust moves like slips of rigid blocks along major slip faults while the lower crust creeps as a flow in the conductive channels.

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Elastic anisotropy is a very common phenomenon in the Earth’s interior, especial for sedimentary rock as important gas and oil reservoirs. But in the processing and interpretation of seismic data, it is assumption that the media in the Earth’s interior is completely elastic and isotropic, and then the methods based on isotropy are used to deal with anisotropic seismic data, so it makes the seismic resolution lower and the error on images is caused. The research on seismic wave simulation technology can improve our understanding on the rules of seismic wave propagation in anisotropic media, and it can help us to resolve problems caused by anisotropy of media in the processing and interpretation of seismic data. So researching on weakly anisotropic media with rotated axis of symmetry, we study systematically the rules of seismic wave propagation in this kind of media, simulate the process with numerical calculation, and get the better research results. The first-order ray tracing (FORT) formulas of qP wave derived can adapt to every anisotropic media with arbitrary symmetry. The equations are considerably simpler than the exact ray tracing equations. The equations allow qP waves to be treated independently from qS waves, just as in isotropic media. They simplify considerably in media with higher symmetry anisotropy. In isotropic media, they reduce to the exact ray tracing equations. In contrast to other perturbation techniques used to trace rays in weakly anisotropic media, our approach does not require calculation of reference rays in a reference isotropic medium. The FORT-method rays are obtained directly. They are computationally more effective than standard ray tracing equations. Moreover the second-order travel time corrections formula derived can be used to reduce effectively the travel time error, and improve the accuracy of travel time calculation. The tensor transformation equations of weak-anisotropy parameters in media with rotated axis of symmetry derived from the Bond transformation equations resolve effectively the problems of coordinate transformation caused by the difference between global system of coordinate and local system of coordinate. The calculated weak-anisotropy parameters are completely suitable to the first-order ray tracing used in this paper, and their forms are simpler than those from the Bond transformation. In the numerical simulation on ray tracing, we use the travel time table calculation method that the locations of the grids in the ray beam are determined, then the travel times of the grids are obtained by the reversed distance interpolation. We get better calculation efficiency and accuracy by this method. Finally we verify the validity and adaptability of this method used in this paper with numerical simulations for the rotated TI model with anisotropy of about 8% and the rotated ORTHO model with anisotropy of about 20%. The results indicate that this method has better accuracy for both media with different types and different anisotropic strength. Keywords: weak-anisotropy, numerical simulation, ray tracing equation, travel time, inhomogeneity

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The Eastern Himalayan Syntaxis (EHS) is one of the strongest deformation area along the Himalayan belt resulted from the collision between Indian plate and the Eurasian Plate since the 50~60Ma, and has sensitivity tracked and preserved the whole collisional processes. It should depend on the detail geological investigations to establish the deformational accommodate mode, and the uplift history, to elucidate the deep structure and the crust-mantle interaction of the Tibet Plateau of the EHS. The deep-seated (Main Mantle Thrusts) structures were exhumed in the EHS. The MMT juxtapose the Gangdese metamorphic basement and some relic of Gangdese mantle on the high Himalayan crystalline series. The Namjagbawa group which is 1200~1500Ma dated by U/Pb age of zircon and the Namla group which is 550Ma dated by U/Pb age of zircon is belong to High Himalayan crystalline series and Gangdese basement respectively. There is some ophiolitic relic along the MMT, such as metamorphic ocean mantle peridotite and metamorphic tholeiite of the upper part of ocean-crust. The metamorphic ocean mantle peridotites (spinel-orthopyroxene peridotite) show U type REE patterns. The ~(87)Sr/~(86)Sr ratios were, 0.709314~0.720788, and the ~(143)Nd/~(144)Nd ratios were 0.512073~0.512395, plotting in the forth quadrant on the ~(87)Sr/~(86)Sr-~(143)Nd/~(144)Nd isotope diagram. Some metamorphic basalt (garnet amphibolite) enclosures have been found in the HP garnet-kynite granulite. The garnet amphibolites can be divided two groups, the first group is deplete of LREE, and the second group is flat or rich LREE, and their ~(87)Sr/~(86)Sr, ~(143)Nd/~(144)Nd ratios were 0.70563~0.705381 and 0.512468~0.51263 respectively. Trace element and isotopic characteristics of the garnet amphibolites display that they formed in the E-MORB environment. Some phlogolite amphibole harzburgites, which exhibit extensive replacement by Phl, Amp, Tc and Dol etc, were exhumed along the MMT. The Phl-Amp harzburgites are rich in LREE and LILE, such as Rb, K etc, and depletes Eu (Eu~* = 0.36 ~ 0.68) and HFSE, such as Nb, Ta, Zr, Hf, P, Ti etc. The trace element indicate that the Phl-Amp harzburgites have island arc signature. Their ~(87)Sr/~(86)Sr are varied from 0.708912 to 0.879839, ~(143)Nd/~(144)Nd from 0.511993 to 0.512164, ε Nd from- 9.2 to - 12.6. Rb/Sr isochrone age of the phlogolite amphibole harzburgite shows the metasomatism took place at 41Ma, and the Amp ~(40)Ar/~(39)Ar cooling age indcate the Phl-Amp harzburgite raising at 16Ma. There is an intense crust shortening resulted from the thrust faults and folds in the Cayu block which is shortened more 120km than that of the Lasha block in 35~90Ma. With the NE corner of the India plate squash into the Gangdese arc, the sinistral Pai shear fault and the dextral Aniqiao shear fault on the both sides of the Great bent of Yalun Zangbu river come into active in 21~26Ma. On the other hand, the right-lateral Gongrigabu strike-slip faults come into activity at the same period, a lower age bound for the Gongrigabu strike-slip fault is estimated to be 23~24Ma from zircon of ion-probe U/Pb thermochronology. The Gongrigabu strike-slip faults connect with the Lhari strike-slip fault in the northwestern direction and with the Saganing strike-slip at the southeastern direction. Another important structure in the EHS is the Gangdese detachment fault system (GDS) which occurs between the sedimental cover and the metamorphic basement. The lower age of the GDS is to be 16Ma from the preliminary 40Ar/39Ar thermochronology of white mica. The GDS is thought to be related to the reverse of the subducted Indian crust and the fast uplift of the EHS. Structural and thermochronology investigation of the EHS suggest that the eastern Tibet and the western Yunnan rotated clockwise around the EHS in the period of 35~60Ma. Later, the large-scale strike-slip faults (RRD, Gaoligong and Saganing fault) prolongate into the EHS, and connect with the Guyu fault and Gongrigabu fault, which suggest that the Indianchia block escape along these faults. Two kind of magmatic rocks in the EHS have been investigated, one is the mantle-derived amphibole gabbro, dioposide diorite and amphibole diorite, another is crust origin biotit-garnet adamellite, biotit-garnet granodiorite and garnet-amphibole-biotite granite. The amphibole gabbro dioposite diorite and amphibole diorite are rich in LREE, and LILE, such as Ba, Rb, Th, K, Sr etc, depleted in HFSE, such as Nb, Ta, Zr, Hf, Ti etc. The ratio of ~(87)Sr/~(86)Sr are from 0.7044 to 0.7048, ~(143)Nd/~(144)Nd are from 0.5126 to 0.5127. The age of the mantle origin magamatic rocks, which result from the partial melt of the raising and decompression anthenosphere, is 8Ma by ~(40)Ar/~(39)Ar dating of amphibole from the diorite. The later crust origin biotite-garnet adamellite, biotite-garnet granodiorite and garnet-amphibole-biotite granite are characterized by aboudance in LREE, and strong depletion of Eu. The ratios of ~(87)Sr-~(86)Sr are from 0.795035 to 0.812028, ~(143)Nd/~(144)Nd from 0.51187 to 0.511901. The ~(40)Ar/~(39)Ar plateau age of the amphibole from the garnet-amphibole-biotite granite is 17.5±0.3Ma, and the isochrone age is 16.8±0.6Ma. Their geochemical characteristics show that the crust-derived magmatic rocks formed from partial melting of the lower curst in the post-collisional environment. A group of high-pressure kaynite-garnet granulites and enclave of high-pressure garnet-clinopyroxene grnulites and calc-silicate grnulites are outcroped along the MMT. The peak metamorphic condition of the high-pressure granulites yields T=800~960 ℃, P=1.4~1.8Gpa, corresponding the condition of 60km depth. The retrograde assemblages of the high-pressure grnulites occur at the condition of T=772.3~803.3 ℃, P=0.63~0.64Gpa. The age of the peak metamorphic assemblages are 45 ~ 69Ma indicated by the zircon U/Pb ion-plobe thermochronology, and the retrograde assemblage ages are 13~26Ma by U/Pb, ~(40)Ar/~(39)Ar thermochronology. The ITD paths of the high-pressure granulites show that they were generated during the tectonic thickening and more rapid tectonic exhumation caused by the subducting of the Indian plate and subsequent break-off of the subducted slab. A great deal of apatite, zircon and sphene fission-track ages, isotopic thermochronology of the rocks in the EHS show that its rapid raising processes of the EHS can be divided into three main periods. There are 35~60Ma, 13~25Ma, 0~3Ma. 3Ma is a turn in the course of raising in the EHS which is characterized by abruptly acceleration of uplifting. The uplift ratios are lower than 1mm .a~(-1) before 3Ma, and higher than 1mm .a~(-1) with a maximum ratio of 30mm .a~(-1) since 3Ma. The bottom (knick point) of the partial anneal belt is 3.8km above sea level in the EHS, and correspond to age of 3Ma determined by fission-track age of apatite. The average uplift ratio is about 1.4 mm .a~(-1) below the knick point. The EHS has raised 4.3km from the surface of 2.36km above sea level since 3Ma estimated by the fossil partial anneal belt of the EHS. We propose a two-stage subduction model (B+A model) basing on Structural, thermochronological, magmatical, metamorphic and geophysical investigations of the EHS. The first stage is the subduction of the Indian continental margin following after the subduction of the Tethys Ocean crust and subsequent collision with the Gangdese arc, and the second stage is the Indian crust injecting into the lower crust and upper mantle of the Tibet plateau. Slab break-off seems to be occurred between these two stages.

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Based on multi-principle (such as structures, tectonics and kinematics) exploratory data and related results of continental dynamics in the Tibetan plateau, the author reconstructed the geological-geophysical model of lithospherical structure and tectonic deformation, and the kinetics boundary conditions for the model. Then, the author used the numerical scheme of Fast Lagrangian Analysis of Continua (FLAC), to stimulate the possible process of the stress field and deformational field in the Tibetan plateau and its adjacent area, since the convergence-collision between the Indian continent and Eurasia continent about 50Ma ago. With the above-mentioned results, the author discussed the relationship between crustal movement in shallow layer and the deformational process in interior layers, and its possible dynamic constraints in deep. At the end of the paper, an integrative model has been put forward to explain the outline images of crust-mantle deformation and coupling in the Tibetan Plateau. (1) The characteristics of crust-mantle structure of the Tibetan plateau have been shown to be very complex, and vertical and horizontal difference is significant. The general characteristics of crust-mantle of the Tibetan plateau may be that it's layering in depth direction, and shows blocking from south to north and belting from east to west, mainly according to the results of about 20 seismic sections, such as wide-angle seismic profiles, CMP, seismic tomography and so on. (2) The crust had shortened about 2200km, while the shortening is different for different block from south to north in the Tibetan plateau. It is about 11.5mm/a in Himalayan block, about 9.0mm/a in Lhas-Gangdese block, about 7.0mm/a in Qiangtang block and Songpan-Ganzi-Kekexili block, about 8.0mm/a in Kunlun-Qaidam, and about ll.Omm/a in Qilian block, since the convergence-collision between the Indian continent and Eurasia continent about 50Ma ago. Which - in demonstrates the shortening rate decreases from south to north, but this rate increases near the north edge of the Tibetan plateau. The crust thickening rate is about 0.4mm/a in the whole Tibetan plateau; and this rate is about 0.5mm/a in Himalayan block, about 0.4mm/a in Lhas-Gangdese block, about 0.3mm/a in Qiangtang block, about 0.2mm/a in Songpan-Ganzi-Kekexili block and about O.lmm/a in Kunlun-Qaidam-Qilian block, since the convergence-collision between the Indian continent and Eurasia continent about 50Ma ago. This implies that the thickening rate decreases in the blocks of the Tibetan plateau. From south to north, the displacement of eastern boundary in the Tibetan plateau is about 37mm/a in Himalayan block, about 45mm/a in Lhas-Gangdese block, about 47mm/a in Qiangtang block, about 43mm/a in Songpan-Ganzi-Kekexili block, and about 35mm/a in Kunlun-Qaidam-Qilian block, since the collision-matching between the Indian continent and Eurasia continent had happened about 50Ma ago. This implies that the rate of eastward displacement is biggest in the middle of plateau, and decreases to both sides. The transition of S-N compression stress field in Tibetan Plateau, since about 28Ma+ ago, may be caused by two reasons: On one hand, the movement direction of Eurasia continent changed from northward to southward about 28Ma± ago in the northern plateau. On the other hand, the front belt that is located between India continent's and Eurasia continent's convergence-collision, had moved southward to high Himalayan from Indus-Brahmaputra suture almost at the same time in southern plateau. Affected by the stress field, the earlier tectonics rotated clockwise, NE and NW conjugate strike-slip faults developed, and the SN rift formed. This indicated that the EW movement started. The ratio between upper crust and lower crust of different blocks from south to north in the Tibetan plateau during the process of deformation are as following: about 3.5~5:1 in Himalayan block, about 1~5: 3-4 (which is about 1:3o--4 in south and about 4~5:3 in north) in Lhas-Gangdese block, about 1:3~447mm/a in these blocks: Which is located to the north of Banggong-nujiang suture.

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In the history of psychology research, more attention had been focused on the relation between local processing and global processing. For the global information and the local information, which is processed earlier? And which is processed faster? Precedence of the global over the local level in visual perception has been well established by Navon with compound stimuli, and Navon’s original study gave rise to many publications, including replications, generalization to other kinds of stimuli (nonverbal material, digits), populations (infants, children, brain-damaged subjects), and tasks (lateral visual hemifield presentation, copy drawing, memory recognition, and recall), and triggered some debate about the conditions in which global precedence is and is not observed (number, size, sparsity, and goodness of the stimuli, exposure duration, etc.). However, whether there is a global advantage or precedence in other cognitive processes was less tested. Most researches had suggested that there was a functional equivalency between visual perception and visual image processing. However, it’s still unknown whether there will be a global advantage on mental rotation. In the present study, we combined the mental rotation task with the compound stimuli to explore whether the global or local advantage also existed at the mental imagery transformation stages. In two pilot studies, the perceptual global precedence was found to be present in a normal/mirror-image judgment task when the stimuli exposure time was short; while the stimuli exposure time was prolonged (stimuli kept available till subjects’ response) the perceptual global precedence was showed to be eliminated. In all of the subsequent experiments, stimili would be presented till subjects’ response. Then mental rotation was added in normal/mirror-image judgment (some of the stimuli were rotated to certain angles from upright) in normal experiments, experiment 1 and 2 observed a global advantage on mental rotation both with a focused-attention design (Experiment 1) and divided-attention design (Experiment 2). Subjects’ reaction times were increased with rotation angles, and the accuracy was decreased with rotation angles, suggesting that subject need a mental rotation to make a normal/mirror judgment. The most important results were that subjects’ response to global rotation was faster than that to local rotation. The analysis of slope of rotation further indicated that, to some extend, the speed of global rotation was faster than that of local rotation. These results suggest a global advantage on mental rotation. Experiment 3 took advantage of the high temporal resolution of event-related potentials to explore the temporal pattern of global advantage on mental rotation. Event-related potential results indicated the parietal P300 amplitude was inversely related to the character orientation, and the local rotation task delayed the onset of the mental-rotation-related negativity at parietal electrodes. None clear effect was found for occipital N150. All these results suggested that the global rotation was not only processed faster than local rotation, but also occurred earlier than local rotation. Experiments 4 and 5 took the effect size of global advantage as the main dependent variable, and visual angle and exposure duration of the stimuli as independent variables, to examine the relationship between perceptual global precedence and global advantage on mental rotation. Results indicated that visual angle and exposure duration did not influence the effect size of global advantage on mental rotation. The global advantage on mental rotation and the perceptual global advantage seemed to be independent but their effects could be accumulated at some condition. These findings not only contribute to revealing a new processing property of mental rotation, but also deepen our understanding of the problem of global/local processing and shed light on the debate on locus of global precedence.