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Effects of Lattice Preferred Orientation and retrogression on Seismic Properties of Eclogite

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Journal of Earth Science 2010年第5期21卷 569-580页

作者：史锋王永锋徐海军章军锋 State Key Laboratory of Geological Processes and Mineral Resources Faculty of Earth Sciences China University of Geosciences

We report here lattice preferred orientations （LPOs） and seismic properties of eclogites from the Sulu （苏鲁） UHP terrane. Our results show strong fabrics in omphacite and amphibole, and approximately random fabrics in garnet with or without strong shape preferred orientations （SPOs）. Dislocation creep is likely to be responsible for the observed omphacite fabrics that vary with geometry and orientation of finite strain ellipsoid. Weak garnet LPOs suggest that garnet did not accommodate plastic strain or was not deformed by dislocation creep with a dominant slip system. The calculated seismic properties of eclogites and their component minerals show a strong correlation with their LPOs. Seismic anisotropies are mostly induced by omphacite component in fresh eclogites and by amphibole component in retrograded eclogites, respectively. retrogression of omphaeite to amphibole and quartz will increase seismic anisotropies but decreases seismic velocities of eclogite. Garnet component increases the seismic velocities but decreases seismic anisotropies of eciogite. Comparison of the calculated and the measured seismic properties of eclogites suggests that both methods resolve comparable results with some discrepancies. Compositional layering can play a very important role in determining the seismic properties of eclogites in addition to LPO.

关键词： eclogite LPO retrogression seismic property deformation mechanism.

<i>β</i>-HCG Level as a Predictive Marker of Pregnancy Progression or retrogression

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Open Journal of Obstetrics and Gynecology 2021年第6期11卷 713-719页

作者： George Gborienemi Simeon Marymar Ezejimofor Newton Cleston Odumoson Department of Medical Laboratory Science Niger Delta University Wilberforce Island Yenagoa Bayelsa State Nigeria Department of Medical Laboratory Science College of Health Science Nnamdi Azikiwe University Awka Nigeria Department of Medical Laboratory Science College of Health Science Niger Delta University Yenagoa Bayelsa State Nigeria

An ordered sequence of biologic events is precursors of the birth of a healthy baby. Hormonal interactions acting as a nexus between the fetus, placenta and mother that controls the establishment and progression of pregnancy and fetal development are very important. We examined the role of Beta-Human Chorionic Gonadotropin (β-HCG) as a predictive marker. Applying radioimmunoassay that utilizes anti-sera generated from specific β-submit of HCG we evaluated the serum β-HCG level in 60 pregnant women in the three trimesters. Results showed that there was consistent increase in concentration that drops gradually and maintained a plateau only to drop from the 40th week of pregnancy. 3 subjects (5%) that had a sudden sharp drop in β-HCG level resulted in complications. Inclusion of β-HCG level screening and monitoring in pregnancy will raise assurance of progress or retrogression in pregnancy. We provide data that can be used as a reference range for β-HCG using this method.

关键词： β-HCG Predictive Marker Pregnancy Progression retrogression

DIAGNOSTIC STUDY OF INTRASEASONAL ANOMALOUS PROGRESSION & retrogression OF SUBTROPICAL HIGH OVER WESTERN PACIFIC

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Journal of Tropical Meteorology 1997年第1期3卷 42-51页

作者：喻世华杨维武

Diagnostic study on two intraseasonal progressive and retrogressive progress of anomalous subtropical high in western Pacific is carried out with the aid of daily 2. 5°×2.5° grid point data of ECMWF inJuly and August of 1980 and 1983. It is revealed that the anomalous progression and retrosression ofthis high is intraseasonally teleconnected with that in the eastern Pacific, shown as low-ftequency wavespropagating westward along a latitudinal wave train across the northern Pacific i the same oscillatory displacement of eastern subtropical high is again triggered off by the variation of convergent sink of uppertropospheric divergent wind field in eastern Pacific, being resulted from anomalous heating from monsoon area in South Asia through trade wind zone in the Pacific Ocean.

关键词： subtropical high anomalous progression & retrogression teleconnection diagnostic study

Microstructures and properties evolution of Al-Zn-Mg-Cu alloy under electrical pulse assisted creep aging

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Advances in Manufacturing 2022年第4期10卷 596-609页

作者： Tian-Jun Bian Heng Li Chao Lei Chang-Hui Wu Li-Wen Zhang State Key Laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an710072People’s Republic of China School of Materials Science and Engineering Xi’an University of TechnologyXi’an710048People’s Republic of China

Creep aging(CA)is a promising forming technology for integral panels with complex ***,how to balance excellent corrosion resistance and strength is still a challenge for CA *** synchronously applying electrical pulse(300 Hz,15 A/mm^(2))in the middle of steady-state CA of Al-Zn-Mg-Cu alloy,the electrically assisted CA(ECA)is proposed to induce retrogression rapidly for realizing a three-step aging(retrogression and re-aging,RRA)in CA to tailor the needed properties *** is compared with conventional CA with one-step aging(peak aging,T6 or over aging,T7),two-step aging(over aging,T73)and RRA in hardness,intergranular corrosion and *** the ECA of pre-aging and re-aging for 20 h plus electropulsing for 10 min,the hardness is 10.5%,20.5%and 18.9%higher than those of CA with T6,T7 and T73 processes,respectively,while the corrosion resistance is higher than T6 process and lower than T7 and T73 *** the hardness and corrosion resistance are comparable to those of the CA with the RRA process,ECA takes one hour less due to the accelerated effect of the electropulsing and is not limited by the thick *** improved comprehensive performance of the ECA sample is due to both fine intragranular precipitatesη′and large discontinuous grain boundary precipitatesη.

关键词： Creep aging(CA) Electrical pulse retrogression Corrosion Hardness Al-Zn-Mg-Cu alloy

The Origin of Spots in Contact Aureoles and Over-Heating of Country Rock Next to a Dyke

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Journal of Earth Science 2018年第5期29卷 1005-1009页

作者： Roger Mason Rong Liu School of Earth Sciences China University of Geosciences

Petrographic comparison of andalusite in the contact aureole of the Fangshan pluton, Zhoukoudian, Beijing, China, and hornfels in the aureole of the Markfield diorite, Leicestershire, Eng- land, shows that spots characteristic of the outer zones of contact metamorphic aureoles did not form during the progressive stage of contact metamorphism, but are pseudomorphs after earlier andalusite with characteristic chiastolite microstructure. The baked margin produced by contact metamorphism of syenite against a dyke in the Houshihushan ring complex, Shanhaiguan, Hebei Province, China, is an unusual feature caused by the dyke＇s role as a feeder to a family of cone-sheets.

关键词： contact metamorphism contact aureole retrogression hornfels spots Zhoukoudian Houshihushan.

The Stretch, Limit and Path Forward for Particle Reinforced Metal Matrix Composites of 7075 Al-Alloys

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Engineering（科研） 2010年第4期2卷 237-256页

作者： Rupa Dasgupta 不详

Al-based metal matrix composites [MMCs] have been the research interest of a wide spectrum of material scientists throughout the world for some over two decades now. The present paper has chosen one alloy system namely the 7xxx series and from an extensive literature review concluded that since the beginning of the new millennium nothing note worthy has been added to the knowledge already gained in the last quarter of the last century except confirm the earlier findings that MMCs if properly fabricated by choosing the processing route and with appropriate size and volume fraction of dispersoids can improve most of the mechanical, corrosion and wear resistant properties of the base alloy. The author’s own research activities using this alloy system for making MMCs that include attempts to improve upon the properties by making composites, ageing and also secondary processing have been included. An attempt has been made to establish the stretch to which improvement is possible in the alloy system by making composites and trying all other routes known for meaningful improvement in properties. Further, the way forward for such particulate composites has been drawn to realise the material scientists’ dream of seeing such MMCs as engineering components. For this, the areas which now need research include mass production of composites, focus on its machining, joining, processing as also reduction in the size of dispersoids are some of the areas that have been identified and discussed in the paper.

关键词： Al-based MMCs 7xxx Series 7075 Alloy Tempering Ageing retrogression And Reageing Hardness Mechanical Properties Wear Properties Extrusion Corrosion Machining Joining Mass Production