The rheological and extrusion behaviour of blends based on phenolphthalein poly(ether-ether-sulfone) and thermotropic liquid crystalline polymer

A novel engineering thermoplastic, phenolphthalein poly (ether-ether-sulfone) (PES-C) was blended with a commercial thermotropic liquid crystalline polymer(TLCP), Vectra A950, up to 30 weight percent of TLCP. A rheometrics dynamic spectrometer (RDS-I) and a CEAST capillary rheometer, a rheoscope 1000 were employed to investigate the melt rheology and extrusion behaviour at both the low and high shearing rates. The morphologies of the blends under different shearing were observed with a scanning electron microscope(SEM) and correlated to the observed rheology. The principal normal stress differences measured with cone-and-plate geometry give a temperature-independent correlation for both blend and PES-C when they are plotted against shear stress. But the extrudate swell of the blends showed a strong temperature dependence at each shear stress. The concentration dependence of extrudate swell shows a contrary behaviour to that of the inorganic filled system. A reasonable hypothesis based on the relaxation and disorientation of TLCP during flowing in the capillary and exiting was given to explain it. The melt fracture was checked after extrusion from capillary and was discussed.

Effects of the compatibilizer PP-g-GMA on morphology and mechanical properties of PP/PC blends

Effects of the compatibilizer polypropylene grafted with glycidyl methacrylate(PP-g-GMA) on the morphology, thermal, rheological and mechanical properties of polypropylene and polycarbonate blends (PP/PC) were studied. It was found that the addition of PP-g-GMA significantly changed their morphology. The mean size of domains reduced from 20 mu m to less than 5 mu m. The dispersed domain size is also strongly dependent upon the content of PP-g-GMA. The interfacial tension of PP/PC/PP-g-GMA (50/30/20) is only about one-tenth of PP/PC (70/30). The crystallization temperature of PP in PP/PC/PP-g-GMA is 5-8 degrees C higher than that of PP in PP/PC blends. Characterization studies based on mechanical properties, differential scanning calorimetry, rheology and morphological evidence obtained by using scanning electron microscopy support the hypothesis that an in-situ copolymer PP-g-PC was formed during the blending process. (C) 1997 Elsevier Science Ltd.

Cure processing modeling and cure cycle simulation of epoxy-terminated poly(phenylene ether ketone) .2. Chemorheological modeling

Chemorheology and corresponding models for an epoxy-terminated poly(phenylene ether ketone) (E-PEK) and 4,4'-diaminodiphenyl sulfone (DDS) system were investigated using a differential scanning calorimeter (DSC) and a cone-and-plate rheometer. For this system, the reported four-parameter chemorheological model and modified WLF chemorheological model can only be used in an isothermal or nonisothermal process, respectively. In order to predict the resin viscosity variation during a stepwise temperature cure cycle actually used, a new model based on the combination of the four-parameter model and the modified WLF model was developed. The combined model can predict the resin viscosity variation during a stepwise temperature cure cycle more accurately than the above two models. In order to simplify the establishment of this model, a new five-parameter chemorheological model was then developed. The parameters in this five-parameter model can be determined through very few rheology and DSC experiments. This model is practicable to describe the resin viscosity variation for isothermal, nonisothermal, or stepwise temperature cure cycles accurately. The five-parameter chemorheological model has also successfully been used in the E-PEK systems with two other curing agents, i.e., the diamine curing agent with the addition of a boron trifluride monoethylamine (BF3-MEA) accelerator and an anhydride curing agent (hexahydrophthalic acid anhydride). (C) 1997 John Wiley & Sons, Inc.

Rheological properties of phenophthalein poly(ether ether ketone)

The rheological properties of the novel engineering thermoplastic phenophthalein poly(ether ether ketone) (PEK-C) have been investigated using both a rotational and a capillary rheometer. The dependence of the viscosity on the shear rate and temperature was obtained. The activation energy was evaluated both from the Arrhenius and the Williams-Landel-Ferry (WLF) equation. An estimate for the proper E(eta) (dependent only on the chemical structure of the polymer) has been found from the WLF equation at temperatures about T-g + 200 degrees C. Measurements of the die swell have been performed. The first normal stress differences were evaluated from the die swell results and compared with the values obtained from the rotational rheometer at low shear rates.

A new thermoplastic polyimide composite based on 1,4-(3,4-dicarboxyphenoxyl)benzene/4,4'-methylene dianiline

New thermoplastic polyimide (PEI) composites based on 1,4-(3,4-discarboxyphenoxyl)benzene/4,4'- methylene dianiline have been fabricated by the approach of polymerization by the approach of polymerization of monomer reactants (PMR). The chemical and physical behavior of the resin during processing are determined by infrared spectroscopy and rheology. The influence of processing conditions on the composite properties is investigated. The processing, physical and mechanical properties of the composites reinforced with different fibers are presented.

IN-SITU COMPOSITE - PHENOLPHTHALEIN POLYETHERSULFONE-THERMOTROPIC LIQUID-CRYSTALLINE POLYMER BLENDS

Phase behavior, thermal, theological and mechanical properties plus morphology have been studied for a binary polymer blend. The blend is phenolphthalein polyethersulfone (PES-C) with a thermotropic liquid crystalline polymer (LCP), a condensation copolymer of p-hydroxybenzoic acid with ethylene terephthalate (PHB-PET). It was found that these two polymers form optically isotropic and homogeneous blends by means of a solvent casting method. The homogeneous blends undergo phase separation during heat treatment. However, melt mixed PES-C/PHB-PET blends were heterogeneous based upon DSC and DMA analysis and SEM examination. Addition of LCP in PES-C resulted in a marked reduction of melt viscosity and thus improved processability. Compared to pure PES-C, the charpy impact strength of the blend containing 2.5% LCP increased 2.5 times. Synergistic effects were also observed for the mechanical properties of blends containing < 10% LCP. Particulates, ribbons, and fibrils were found to be the typical morphological units of PHB-PET in the PES-C matrix, which depended upon the concentration of LCP and the processing conditions.

A NEW THERMOPLASTIC POLYIMIDE COMPOSITE PREPARED BY THE POLYMERIZATION OF MONOMER REACTANTS APPROACH

A novel amorphous thermoplastic polyimide (PTI) is being developed as a potential matrix resin for advanced composites. This paper describes the manufacture of the resin, prepreg, and processing of the composite. The chemical and physical behavior of the resin during the processing was determined by infrared spectroscopy and rheology. The influence of processing conditions on the composite properties was investigated. Mechanical properties of the unidirectional carbon fiber/PTI laminates were also presented.

CHARACTERIZATION OF BLENDS OF POLYPROPYLENE WITH A SEMIRIGID LIQUID-CRYSTAL COPOLYESTER

Blends with a liquid-crystal polymers (LCP) as one component show, in general, very interesting properties. Reduction of shear visocity and improvement of mechanical properties are very remarkable. High melting temperatures and high costs of the LCP limit the use of these blends. A new class of thermotropic LCPs with flexible spaces, with relatively low melting temperatures, can overcome the first problem. In this work, rheological and mechanical properties of blends of polypropylene with low contents of this LCP are presented. Torque during extrusion and viscosity decrease with LCP content. Elastic modulus is remarkably increased when the LCP phase is oriented.

Numerical modeling of water wave interaction with a soft mud bed

A vertical 2-D numerical model is presented for simulating the interaction between water waves and a soft mud bed. Taking into account nonlinear rheology, a semi-empirical rheological model is applied to this water-mud model, reflecting the combined visco-elasto-plastic properties of soft mud under such oscillatory external forces as water waves. In order to increase the resolution of the flow in the neighborhood of both sides of the inter-surface, a logarithmic grid in the vertical direction is employed for numerical treatment. Model verifications are given through comparisons between the calculated and the measured mud mass transport velocities as well as wave height changes.

用波动方程建立蠕动爬行攻泥机器人海底土力学运动模型

针对目前国内海底蠕动爬行机器人攻打千斤洞的特点 ,在对海洋沉积土的工程性质进行分析的基础上 ,利用流变力学的理论 ,提出用波动方程来建立攻泥机器人周期性冲击土壤的力学模型 ,用后向差分法解波动方程 ,得到土壤的位移和变形公式 ,确定土壤对攻泥机的阻力 .通过对模型的仿真 ,证明了用该模型计算阻力的可行性 .

青藏高原横波速度与各向异性结构及其壳幔形变印迹

As the most spectacular and youngest case of continental collision on the Earth, to investigate the crust and mantle of Tibetan plateau, and then to reveal its characters of structure and deformation, are most important to understand its deformation mechanism and deep process. A great number of surface wave data were initially collected from events occurred between 1980 and 2002, which were recorded by 13 broadband digital stations in Eurasia and India. Up to 1,525 source-station Rayleigh waveforms and 1,464 Love wave trains were analysed to obtain group velocity dispersions, accompanying with the detail and quantitative assessment of the fitness of the classic Ray Theory, errors from focal and measurements. Assuming the model region covered by a mesh of 2ox2o-sized grid-cells, we have used the damped least-squares approach and the SVD to carry out tomographic inversion, SV- and SH-wave velocity images of the crust and upper mantle beneath the Tibetan Plateau and surroundings are obtained, and then the radial anisotropy is computed from the Love-Rayleigh discrepancy. The main results demonstrate that follows, a) The Moho beneath the Tibetan Plateau presents an undulating shape that lies between 65 and 74 km, and a clear correlation between the elevations of the plateau and the Moho topography suggests that at least a great part of the highly raised plateau is isostatically compensated. b) The lithospheric root presents a depth that can be substantiated at ~140 km (Qiangtang Block) and exceptionally at ~180 km (Lhasa Block), and exhibits laterally varying fast velocity between 4.6 and 4.7 km/s, even ~4.8 km/s under northern Lhasa Block and Qiangtang Block, which may be correlated with the presence of a shield-like upper mantle beneath the Tibetan Plateau and therefore looked as one of the geophysical tests confirming the underthrusting of India, whose leading edge might have exceeded the Bangong-Nujiang Suture, even the Jinsha Suture. c) The asthenosphere is depicted by a low velocity channel at depths between 140 and 220 km with negative velocity gradient and velocities as low as 4.2 km/s; d) Areas in which transverse radial anisotropy is in excess of ~4% and 6% on the average anisotropy are found in the crust and upper mantle underlying most of the Plateau, and up to 8% in some places. The strength, spatial configuration and sign of radial anisotropy seem to indicate the existence of a regime of horizontal compressive forces in the frame of the convergent orogen at the same time that laterally varying lithospheric rheology and a differential movement as regards the compressive driving forces. e) Slow-velocity anomalies of 12% or more in southern Tibet and the eastern edge of the Plateau support the idea of a mechanically weak middle-to-lower crust and the existence of crustal flow in Tibet.

喜马拉雅西构造结区岩石圈演化三维有限元动力学数值模拟

The past three decades have seen numerous attempts to numerically model stress and strain patterns in the lithosphere of the Earth on both global and regional scales. This efforts have been indispensable in identifying the features we need to include in our endeavour to develop better models of our planet’s lithosphere and they have also raised our awareness for the many unresolved issue in the deep geodynamical issues that need to be addressed in the future. Nonetheless, in most models, the lithosphere is treated as a single layer with depth-averaged properties, and as the same distribution in the stress and strain fields, and as deforming under plane strain. All these above make a great hander for its reality and degree of recognition. As the beginning in this paper, some principal numerical models and results on the evolution of Tibetan plateau are reviewed and analyzed. Then, the geological and geophysical expedition on the Western Himalayan Syntaxis is briefly reviewed. Furthermore, we analysis the feature in deep geophysical field studies in this area and adjacent regions. Because, for most continents, stress models driven by plate boundary forces have successfully reproduced the main characteristics of the stress and strain field, we present a set of three-dimensional models of lithosphere system for a simplified geometry of the Western Himalayan Syntaxis area and its adjacent regions, where we try to match the first-order characteristics of the stress and strain fields of lithosphere since 10 Ma, and deformation and geodynamical evolution process in former 2Ma. Of course, the kinematic boundary conditions of the stress models driven by plate boundary forces were applied. The rheology plays a significant role in the lithospheric tectonics, which lead to different rheological parameters were used in different works although the have the same constitutive equations in models. So, in this paper we do not aim to produce all characteristics of the Western Himalayan Syntaxis areas’ stress and strain fields by the choices of various parameters, but rather the dynamic response between various rheological parameters and stress and strain fields. We have chosen to concentrate on the importance of rheology and lateral strength variations for lithospheric stress and strain patterns and use our findings to build a model of the Western Himalayan Syntaxis areas. In doing so, we want to go beyond purely elastic models or purely viscoelastic models. Compared the results of the crust viscosity in the Western Himalayan Syntaxis areas, we believed that, when various viscoelastic models are adopted, the selection of the coefficient of viscosity in the Western Syntaxis area has important influence on the its uplifts and evolutions. A wider uplift ranges and gently elevation was observed at the same time when a lower viscosity was used in our models, and vice versa. Data of stress magnitudes are not available, but it is clear that the stress levels must be at or below the failure threshold of rock under compression. Under these criteria, the calculation results show that the viscosity in the Western Syntaxis area should be smaller than 1023Pa.s When elastic model is adopted in relatively rigid Tarim basin, obvious changes are induced to the stress and strain fields of the whole Western Syntaxis area. We found that rigid block of lithosphere reduced stress levels within its interior and that, at the edges of such regions, stress orientation can change. Furthermore there is no evidence that such rigid regions act as stress barriers in that they shield areas in opposite sides of the structure from the influence of one another. In our models, the upper crustal material of the Western Syntaxis area does not turns to move westward. Whereas, because of the stress and strain fields have been decoupling at the interior of the lithosphere, we can get the results that the deep material must not move westward.

南海北部大陆边缘盆地深部地热特征用地球动力学演化

This report is a conclusion of the major research outcome during my post-doctoral residence of research and work. Its content covers the researches of the deep thermal characteristic and dynamics evolution beneath the northern margin basin of South China Sea. In this report, the each other action and effect between lithosphere ad mantle convection were regarded by the combine of deep and shallow study, subdivision from whole to part, and pay equal attention to determine the nature and fixed quantity. The investigative method we used in this report is geothermal and gravity methods. By the help of geological model and geophysics modeling, we calculated lithosphere thermal structure, rheology structure and mantle convection. Firstly, the report introduces concisely the purpose and the previous achievement to this research. Then, it analyzed the characteristic of heat flow on South China Sea. The structure of deep temperature and thermal has been calculated in some models of heat generation and conduction. The rock rheology structure also was computed by the relationship between temperature and viscosity. All these calculations were finished under the guidelines of combine with geology and geophysics. Meanwhile, the fields both deep mantle convection and small scale upper mantle convection are computed. Beside, the density and temperature disorder resulted by mantle convection were also computed with the convection field. After these, the report bring the contribution of local field of mantle convection, thermal construct and effective viscosity beneath the northern margin basin of South China Sea. And, base on the tectonic background and evolution feature, this report discussion the evolution mechanism of south China Sea and its northern margin basin. The end of this report, the main conclusion of this research was summarized and brings out.

云南岩石圈流变学及多震层孕震环境

The Study on rheology of the lithosphere and the environments of the seismogenic layer is currently the basic project of the international earthquake research. Yunnan is the ideal place for studying this project. Through the multi-disciplinary comprehensive study of petrology, geophysics, seismo-geology, rock mechanics, etc., the depth-strength profiles of the lithosphere have been firstly constructed, and the seismogenic layer and its geophysical and tectonic environments in Yunnan have been systematically expounded in this paper. The related results achieved are of the important significances for further understanding the mechanism of strong earthquake generation, dividing the potential foci and exposing recent geodynamical processes in Yunnan. Through the comprehensive contrast of the metamorphic rocks in early and middle Proterozoic outcropping on the surface, DSS data and experimental data of rock seismic velocity under high temperature and high pressure, the petrological structure of the crust and upper mantle has been studied on Yunnan: the upper, middle and lower crust is composed of the metamorphic rocks of greenschist, amphibolite and granulite facies, respectively or granitoids, diorites and gabbros, respectively, and the upper mantle composed of the peridotites. Through the contrast studies of the heat flow and epicenters of the strong earthquakes, the distribution of the geotemperature and the data of focal depth, the relationship of between seismicity and geothermal structure of the lithosphere in Yunnan has been studied: the strong earthquakes with magnitude M ≥ 6.0 mainly take place at the geothermal gradient zone, and the seismic foci densely distribute between 200～500 ℃ isogeotherms. On the basis of studies of the rock properties and constituents of the crust and upper mantle and geothermal structure of the lithosphere, the structure of the rheological stratification of the lithosphere has been studied, and the corresponding depth-strength profiles have been constructed in Yunnan. The lithosphere in majority region of Yunnan has the structure of the rheological stratification, i.e. the brittle regime in the upper crust or upper part of the upper crust, ductile regime in the middle crust or lower part of the upper crust to middle crust, ductile regime in the lower crust and ductile regime in the subcrustal lithosphere. The rheological stratification has the quite marked lateral variations in the various tectonic units. The distributions of the seismogenic layer have been determined by using the high accurate data of focal depth. Through the contrast of the petrological structure, the structure of seismic velocity, electric structure, geotemperature structure, and rheological structure and the study of the focal mechanism in the seismogenic layer, the geophysical environments of the seismogenic layer in Yunnan have been studied. The seismogenic layer in Yunnan is located at the depths of 3 ～ 20 km; the rocks in the seismogenic layer are composed of the metamorphic rocks of greenschist to amphibolite facies (or granites to diorites); the seismogenic layer and its internal focal regions of strong earthquakes have the structure of medium properties with the relatively high seismic velocity, high density and high resistivity; there exists the intracrustal low seismic velocity and high conductivity layer bellow the seismogenic layer, the geotemperature is generally 100～500 ℃ in the depth range in which the seismogenic layer is located. The horizontal stress field predominates in the seismogenic layer, the seismogenic layer corresponds to the brittle regime of the upper crust or brittle regime of the upper crust to semibrittle regime of the middle crust. The formation of the seismogenic layer, preparedness and occurrence of the strong earthquakes is the result of the comprehensive actions of the source fault, rock constituent, structure of the medium properties, distribution of the geotemperature, rheological structure of the seismogenic layer and its external environments. Through the study of the structure, active nature, slip rate, segmentation of the active faults, and seismogenic faults, the tectonic environments of the seismogenic layer in Yunnan have been studied. The source faults of the seismogenic layer in Yunnan are mainly A-type ones and embody mainly the strike slip faults with high dip angle. the source faults are the right-lateral strike slip ones with NW-NNW trend and left-lateral strike slip ones with NE-NEE trend in Southwestern Yunnan, the right-lateral strike slip ones with NNW trend and left-lateral strike slip ones with NNE trend (partially normal ones) in Northwestern Yunnan, the right-lateral strike slip ones with NWW trend in Central Yunnan and left-lateral strike slip ones with NW-NNW trend in Eastern Yunnan. Taking Lijiang earthquake with Ms = 7.0 for example. The generating environments of the strong earthquake and seismogenic mechanical mechanism have been studied: the source region of the strong earthquake has the media structure with the relatively high seismic velocity and high resistivity, there exists the intracrustal low velocity and high conductivity layer bellow it and the strong earthquakes occur near the transitional zone of the crustal brittle to ductile deformation. These characteristics are the generality of the generating environments of strong earthquakes. However, the specific seismogenic tectonic environments and action of the stress field of the seismic source in the various regions, correspondingly constrains the dislocation and rupture mechanical mechanism of source fault of strong earthquake.

大别山硬玉石英岩带中的水

The Dabie Mountains is a collisional orogenic belt between the North China and Yantze Continental plates. It is the eastern elongation of the Tongbai and Qingling orogen, and is truncated at its east end by the Tan-Lu fault. Jadeite-quartzite belt occurs in the eastern margin of UHPMB from the Dabie Mountains. Geochemical features indicate that the protoliths of the jadeite-quartzite and associated eclogite to be supracrustal rocks. The occurrence of micro-inclusions of coesite in jadeite and garnet confirmed that the continental crust can be subducted to great depth (8 0-100km) and then exhumed rapidly with its UHP mineral signature fairly preserved. Therefore, study of UHP jadeite-quartzite provides important information on subduction of continental crustal rocks and their exhumation histories, as well as the dynamics of plate tectonic processes at convergent margins. The purpose of this paper is to investigate the presence of hydrous component in the jadeite-quartzite belt, significant natural variations in the hydrous component content of UHP minerals and to discuss the role of water in petrology, geochemistry and micro-tectonic. On the basis of our previous studies, some new geological evidences have been found in the jadeite-quartzite belt by researches on petrography, mineralogy, micro-tectonic, hydrous component content of UHP minerals and combined with the study on rheology of materials using microprob, ER, TEM. By research and analysis of these phenomenona, the results obtained are as follows: 1. The existence of fluid during ultra-high pressure metamorphic process. Jadeites, omphacite, garnet, rutile, coesite and quartz from the jadeite-quartzite belt have been investigated by Fourier transform infrared spectrometer and TEM. Results show that all of these minerals contain trace amount of water which occur as hydroxyl and free-water in these minerals. The two-type hydrous components in UHP minerals are indicated stable in the mantle-depth. The results demonstrated that these ultra-high pressure metamorphic minerals, which were derived from continental crust protoliths, they could bring water into the mantle depth during the ultra-high pressure metamorphism. The clusters of water molecules within garnet are very important evidence of the existence of fluid during ultra-high pressure metamorphic process. It indicated that the metamorphic system was not "dry"during the ultra-high pressure stage. 2.The distribution of hydrous component in UHP minerals of jadeite-quartzite. The systematic distribution of hydrous components in UHP minerals are a strong indication that water in these minerals, are controlled by some factors and that the observed variations are not of a random nature. The distribution and concentration of hydrous component is not only correlated with composition of minerals, but also a function of geological environment. Therefore, the hydrous component in the minerals can not only take important part in the UHP metamorphic fluid during subduction of continental crustal rocks, but also their hydroxyl transported water molecules with decreasing pressure during their exhumation. And these water molecules can not only promote the deformation of jadeite through hydrolytic weakening, but also may be the part of the retrograde metamorphic fluid. 3.The role of water in the deformed UHP minerals. The jadeite, omphacite, garnet are strong elongated deformation in the jadeite-quartzite from the Dabie Mountains. They are (1) they are developed strong plastic deformation; (2) developed dislocation loop, dislocation wall; (3) the existence of clusters of water molecular in the garnet; and (4) the evolution of micero-tectonic from clusters of water molecular-dislocation loop in omphacite. That indicated that the water weakening controlled the mechanism of deformed minerals. Because the data presented here are not only the existence of clusters of water molecular in the garnet, but also developed strong elongation, high density of dislocation and high aspect ratios, adding microprobe data demonstrate the studied garnet crystals no compositional zoning. Therefore, this indicates that the diffusion process of the grain boundary mobility did not take place in these garnets. On the basis of above features, we consider that it can only be explained by plastic deformation of the garnets. The clusters of water molecules present in garnet was directly associated with mechanical weakening and inducing in plastic deformation of garnet by glissile dislocations. Investigate of LPO, strain analysis, TEM indicated that these clinopyroxenes developed strong elongation, high aspect ratios, and developed dislocation loop, dislocation wall and free dislocations. These indicated that the deformation mechanism of the clinopyroxenes plastically from the Dabie Mountains is dominant dislocation creep under the condition of the UHP metamorphic conditions. There are some bubbles with dislocation loops attached to them in the omphacite crystal. The bubbles attached to the dislocation loops sometimes form a string of bubble beads and some loops are often connected to one another via a common bubble. The water present in omphacite was directly associated with hydrolitic weakening and inducing in plastic deformation of omphacite by dislocations. The role of water in brittle deformation. Using microscopy, deformation has been identified as plastic deformation and brittle deformation in UHP minerals from the Dabie Mountains. The study of micro-tectonic on these minerals shows that the brittle deformation within UHP minerals was related to local stresses. The brittle deformation is interpreted as being caused by an interaction of high fluid pressure, volume changes. The hydroxyl within UHP minerals transported water molecules with decreasing pressure due to their exhumation. However, under eclogite facies conditions, the litho-static pressure is extreme, but a high fluid pressure will reduce the effective stress and make brittle deformation possible. The role of water in prograde metamorphism. Geochemical research on jadeite-quartzite and associated eclogite show that the protoliths of these rocks are supracrustal rocks. With increasing of temperature and pressure, the chlorite, biotite, muscovite was dehydrous reaction and released hydrous component during the subduction of continental lithosphere. The supracrustal rocks were transformed UHP rocks and formed UHP facies assemblage promotely by water introduction, and was retained in UHP minerals as hydrous component. The water within UHP minerals may be one of the retrograde metamorphic fluids. Petrological research on UHP rocks of jadeite-quartzite belt shows that there was existence of local fluids during early retrograde metamorphism. That are: (1) coronal textures and symplectite around relict UHP minerls crystals formed from UHP minerls by hydration reactions; (2) coronal textures of albite around ruitle; and (3) micro-fractures in jadeite or garnet were filled symplectite of Amp + PI + Mt. That indicated that the reactions of early retrograde metamorphism dependent on fluid introduction. These fluids not only promoted retrograde reaction of UHP minerals, but also were facilitate to diffuse intergranular and promote growth in minerals. Therefore, the hydrous component in the UHP minerals can not only take important part in the UHP metamorphic fluid during subduction of continental crustal rocks, but also their hydroxyl transport water molecules with decreasing pressure and may take part in the retrograde metamorphic fluid during their exhumation. 7. The role of water in geochemistry of UHP jadeite-quartzite. Geochemical research show that there are major, trace and rare earth element geochemical variations in the jadeite-quartzite from the Changpu district of Dabie Mountains, during retrograde metamorphic processes from the jadeite-quartzite--gneiss. The elements such as SiO_2、FeO、Ba、Zr、Ga、La、Ce、PTN Nd% Sm and Eu increase gradually from the jadeite-quartzite to retrograded jadeite-quartzite and to gneiss, whilst TiO_2. Na_2CK Fe2O_3、Rb、Y、Nb、Gd、Tb、Dy、Ho、Er、Tm、Yb decrease gradually. And its fO_2 keep nearly unchanged during early retrograde metamorphism, but decreased obviously during later retrograde metamorphism. These indicate that such changes are not only controlled by element transformation between mineralogical phases, but also closely relative to fluid-rock interaction in the decompression retrograde metamorphic processes.