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Dual Cold Crystallization Kinetics of Heterogeneous Amorphous Structure in Poly(L-lactide)upon Extensional Flow 认领 引用
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作者 Jie Zhang Xin-Rui Gao +5 位作者 Zhi-Kang Ni De-Zhuang Jia Hao Lin Hua-Dong Huang Gan-Ji Zhong Zhong-Ming Li 《Chinese Journal of Polymer Science》 SCIE EI CAS CSCD 2025年第7期1231-1239,共9页
Poly(L-lactide)(PLLA),a leading biodegradable polyester,has demonstrated potential as a sustainable alternative,owing to its excellent biodegradability and rigidity.However,their slow crystallization kinetics and p... Poly(L-lactide)(PLLA),a leading biodegradable polyester,has demonstrated potential as a sustainable alternative,owing to its excellent biodegradability and rigidity.However,their slow crystallization kinetics and poor heat resistance limit their application scope.Recent advances have highlighted that the combination of extensional flow and thermal fields can achieve toughness–stiffness balance,high transparency,and good heat resistance.However,the effect of extensional flow on the post-non-isothermal crystallization of PLLA during heating and the resulting crystalline texture remains unclear.In this study,PLLA with a heterogeneous amorphous structure and oriented polymorph was prepared by extensional flow.The effect of heterogeneous amorphous structures on non-isothermal crystallization kinetics during the heating process was studied by thermal analysis,polarized optical microscopy,infrared spectroscopy,and ex situ/in situ X-ray characterization.These results clearly illustrate that extensional flow enhances the formation of oriented crystalline structures,accelerates non-isothermal crystallization,and modulates the polymorphic composition of PLLA.Moreover,an unexpected dual cold-crystallization behavior is identified in ordered PLLA samples upon extensional flow,which is from the extensional flow-induced heterogeneous amorphous phase into α' phase(low-temperature peak)and the pristine amorphous phase intoαphase(high-temperature peak).The extensional flow primarily promotes the formation of the more perfectαandα'phases,but has a negative effect on the final content ofαphase formed after cold crystallization andα'-to-αphase transformation.The findings of this work advance the understanding of PLLA non-isothermal crystallization after extensional flow and offer valuable guidance for high-performance PLLA upon heat treatment in practical processing. 展开更多
关键词 Poly(L-lactide) Extensional flow Heterogeneous amorphous structure Dual cold crystallization
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Early Paleozoic Bimodal Magmatism Documents the Transition from Collisional to Extensional Tectonics within the Central Himalaya 认领 引用 被引量：1
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作者 YIN Zhiqiang LIU Longqiang +4 位作者 LÜXiaochun LI Nan ZHU Lidong LIU Qiang HA Erjia 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2025年第3期679-692,共14页
The tectonic setting of the Himalaya during the Early Paleozoic has been a subject of enduring debate within the scientific community.Newly discovered bimodal intrusive rocks from comprehensive field geological invest... The tectonic setting of the Himalaya during the Early Paleozoic has been a subject of enduring debate within the scientific community.Newly discovered bimodal intrusive rocks from comprehensive field geological investigation in the central mountain range were subjected to petrology,zircon U-Pb geochronology,zircon Hf isotopes and whole-rock geochemistry analyses.The Palie bimodal intrusive rocks,comprising amphibolite and granitic gneiss,were formed at~489 Ma.The amphibolite exhibits geochemical characteristics consistent with N-MORB,while the granitic gneiss is classified as high potassium calc-alkaline peraluminous S-type granite.Both igneous rocks exhibit negative zirconεHf(t)values and display ancient TDMCages.In conjunction with regional geological survey findings,it can be inferred that the formation of the Palie bimodal intrusive rocks occurred within a post-collision extensional tectonic setting.The amphibolite genesis involved partial melting of an enriched lithospheric mantle with some crustal assimilation,whereas the origin of the granitic gneiss can be attributed to partial melting of pre-existing felsic crust.Our data indicate that during the Early Paleozoic,the Himalaya underwent a transition from a pan-African collisional setting to post-collisional extensional tectonics. 展开更多
关键词 igneous rocks tectonics bimodal magmatism post-collision extension Ordovician Palie
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Inversion of two-phase extensional basin systems during subduction of the Paleo-Pacific Plate in the SW Korean Peninsula:Implication for the Mesozoic “Laramide-style” orogeny along East Asian continental margin 认领 引用 被引量：3
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作者 Seung-Ik Park Jungrae Noh +4 位作者 Hee Jun Cheong Sanghoon Kwon Yungoo Song Sung Won Kim M.Santosh 《Geoscience Frontiers》 SCIE CAS CSCD 2019年第3期909-925,共17页
During subduction, continental margins experience shortening along with inversion of extensional sedimentary basins. Here we explore a tectonic scenario for the inversion of two-phase extensional basin systems, where ... During subduction, continental margins experience shortening along with inversion of extensional sedimentary basins. Here we explore a tectonic scenario for the inversion of two-phase extensional basin systems, where the Early-Middle Jurassic intra-arc volcano-sedimentary Oseosan Volcanic Complex was developed on top of the Late Triassic-Early Jurassic post-collisional sequences, namely the Chungnam Basin. The basin shortening was accommodated mostly by contractional faults and related folds. In the basement, regional high-angle reverse faults as well as low-angle thrusts accommodate the overall shortening, and are compatible with those preserved in the cover. This suggests that their spatial and temporal development is strongly dependent on the initial basin geometry and inherited structures.Changes in transport direction observed along the basement-sedimentary cover interface is a characteristic structural feature, reflecting sequential kinematic evolution during basin inversion. Propagation of basement faults also enhanced shortening of the overlying sedimentary cover sequences. We constrain timing of the Late Jurassic-Early Cretaceous(ca. 158-110 Ma) inversion from altered K-feldspar 40 Ar/39 Ar ages in stacked thrust sheets and K-Ar illite ages of fault gouges, along with previously reported geochronological data from the area. This "non-magmatic phase" of the Daebo Orogeny is contemporaneous with the timing of magmatic quiescence across the Korean Peninsula. We propose the role of flat/low-angle subduction of the Paleo-Pacific Plate for the development of the "Laramide-style" basement-involved orogenic event along East Asian continental margin. 展开更多
关键词 Two-phase extensional basin systems Paleo-Pacific Plate Inversion tectonics “Laramide-style” orogeny East Asian continental margin
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Sandbox Modeling of the Fault-increment Pattern in Extensional Basins 认领 引用 被引量：6
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作者 Geng Changbo Tong Hengmao +1 位作者 He Yudan Wei Chunguang 《Petroleum Science》 SCIE CAS 2007年第2期29-34,共6页
Three series of sandbox modeling experiments were performed to study the fault-increment pattern in extensional basins. Experimental results showed that the tectonic action mode of boundaries and the shape of major bo... Three series of sandbox modeling experiments were performed to study the fault-increment pattern in extensional basins. Experimental results showed that the tectonic action mode of boundaries and the shape of major boundary faults control the formation and evolution of faults in extensional basins. In the process of extensional deformation, the increase in the number and length of faults was episodic, and every ＇episode＇ experienced three periods, strain-accumulation period, quick fault-increment period and strain-adjustment period. The more complex the shape of the boundary fault, the higher the strain increment each ＇episode＇ experienced. Different extensional modes resulted in different fault-increment patterns. The horizontal detachment extensional mode has the ＇linear＇ style of fault-increment pattern, while the extensional mode controlled by a listric fault has the ＇stepwise＇ style of fault-increment pattern, and the extensional mode controlled by a ramp-flat boundary fault has the ＇stepwise-linear＇ style of fault-increment pattern. These fault-increment patterns given above could provide a theoretical method of fault interpretation and fracture prediction in extensional basins. 展开更多
关键词 Extensional basin sandbox modeling fault-increment pattern boundary fault
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Coulomb stress evolution along the Kongur Extensional System since 1895 and present seismic hazard 认领 引用 被引量：3
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作者 Wei Xiong Xuejun Qiao +2 位作者 Gang Liu Wei Chen Zhaosheng Nie 《Geodesy and Geodynamics》 2019年第1期1-9,共9页
The present-day tectonic activities on the northeastern margin of the Pamir Plateau are mainly E-W oriented extensions, among which the Kongur Extensional System(KES) plays an important role in the internal expansion ... The present-day tectonic activities on the northeastern margin of the Pamir Plateau are mainly E-W oriented extensions, among which the Kongur Extensional System(KES) plays an important role in the internal expansion of the Pamir. As the largest earthquake since Taxkorgan earthquakes in 1895 and 1896, the Aketao earthquake occurred on the Muji fault on the northern portion of the KES in 2016. Since then, the trend of seismic activities along the KES has been paid much attention to. Based on the visco elastic layered lithosphere model, we calculate the co-seismic and post-seismic stress changes caused by five historical earthquakes on the KES and its adjacent areas since 1895, and analyze the interaction among strong earthquakes. The results show that all of the historical earthquakes after 1895 occurred in the areas where the co-seismic and post-seismic Coulomb stress increased. Coulomb stress loading at the hypocenters of the 1896 Taxkorgan earthquake, the 1974 Markansu earthquake and the 2016 Aketao earthquake were 0.251 MPa, 0.013 MPa and 0.563 MPa, respectively. The three earthquakes were catalyzed by such variations. The historical earthquakes increased the stress state on most segments of the Southern Kungai Mountain fault and Kongur fault along the KES. In particular, we can identify 2 visible earthquake gaps with increasing seismic hazard formed on the Qimugan segment and Bulunkou segment of the KES. The Qimugan section and the Bulunkou section are located at the fault transition zone with concentrated stress and high extension rate, so great attention should be paid to their seismic hazard at present day. 展开更多
关键词 Kongur extensional system Coulomb stress Stress accumulation Seismic hazard
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Mesozoic Thrust-Nappe and Extensional Structure Frameworks in the East Segment of Southeast Yangtze Block, Southeast China 认领 引用 被引量：3
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作者 Xinqi Yu Ziwei Chen +5 位作者 Jun Hu Yan Zeng Xiu Liu Yu He Zishen Wang Linghui Meng 《Journal of Earth Science》 SCIE CAS CSCD 2020年第4期772-794,共23页
Multi-stage Mesozoic thrust-nappe and extensional structures are distributed in the east segment of the Southeast Yangtze Block situated in the junction region of Zhejiang-Jiangxi-Anhui provinces. The features and gen... Multi-stage Mesozoic thrust-nappe and extensional structures are distributed in the east segment of the Southeast Yangtze Block situated in the junction region of Zhejiang-Jiangxi-Anhui provinces. The features and genetic mechanism of the deformations were analyzed after a detailed field observation of their distribution, geometry, and kinematics. In addition, the time sequences of the thrust and extensional structures were determined by combining the results of the comparative analysis with the chronological evidence of strata and magmatic rocks cut by a fault or formed after a fault according to field facts. This study identified three stages of the nappe structures and at least two stages of the extensional structures during the Mesozoic. The geotectonic setting of the nappe and extensional structures was considered to be related to the different geodynamics in the study area including the Early Mesozoic geological event, i.e., N-S compression, forming Lantian fault, etc.;the Late Mesozoic flat-slab subduction, forming Xiaoxi thrust fault and tectonic window;and the roll-back of the paleoPacific Plate, forming extensional structures like basin marginal fault;the last compression, forming Wucheng-Shenxian fault. These findings provide additional evidence for remodeling the tectonic and geodynamic evolution of Southeast China. 展开更多
关键词 Mesozoic nappe structure extensional structure time sequence east segment of the Southeast Yangtze Block
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Extensional tectonics and sedimentary response of the Early—Middle Cambrian passive continental margin,Tarim Basin,Northwest China 认领 引用 被引量：10
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作者 Zhiqian Gao Tailiang Fan 《Geoscience Frontiers》 SCIE CAS 2012年第5期661-668,共8页
The fact that several half-grabens and normal faults developed in the Lower--Middle Cambrian of Tazhong(central Tarim Basin)and Bachu areas in Tarim Basin,northwest China,indicates that Tarim Basin was under extension... The fact that several half-grabens and normal faults developed in the Lower--Middle Cambrian of Tazhong(central Tarim Basin)and Bachu areas in Tarim Basin,northwest China,indicates that Tarim Basin was under extensional tectonic setting at this time.The half-grabens occur within a linear zone and the normal faults are arranged in en echelon patterns with gradually increasing displacement eastward.Extensional tectonics resulted in the formation of a passive continental margin in the southwest and a cratonic margin depression in the east,and most importantly,influenced the development of a three-pronged rift in the northeast margin of the Tarim Basin.The fault system controlled the development of platform--slope--bathyal facies sedimentation of mainly limestone-dolomite-gypsum rock-saline rock-red beds in the half-grabens.The NW-SE trending half-grabens reflect the distribution of buried basement faults. 展开更多
关键词 Passive continentalmargin Extensional tectonics Half-grabens Normal faulting Tarim Basin Northwest China
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Quantitative evaluation of lateral sealing of extensional fault by an integral mathematical-geological model 认领 引用 被引量：2
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作者 LYU Yanfang HU Xinlei +5 位作者 JIN Fengming XIAO Dunqing LUO Jiazhi PU Xiugang JIANG Wenya DONG Xiongying 《Petroleum Exploration and Development》 2021年第3期569-580,共12页
To evaluate the lateral sealing mechanism of extensional fault based on the pressure difference between fault and reservoir, an integral mathematical-geological model of diagenetic time on diagenetic pressure consider... To evaluate the lateral sealing mechanism of extensional fault based on the pressure difference between fault and reservoir, an integral mathematical-geological model of diagenetic time on diagenetic pressure considering the influence of diagenetic time on the diagenetic pressure and diagenetic degree of fault rock has been established to quantitatively calculate the lateral sealing ability of extensional fault. By calculating the time integral of the vertical stress and horizontal in-situ stress on the fault rock and surrounding rock, the burial depth of the surrounding rock with the same clay content and diagenesis degree as the target fault rock was worked out. In combination with the statistical correlation of clay content, burial depth and displacement pressure of rock in the study area, the displacement pressure of target fault rock was calculated quantitatively. The calculated displacement pressure was compared with that of the target reservoir to quantitatively evaluate lateral sealing state and ability of the extensional fault. The method presented in this work was used to evaluate the sealing of F1, F2 and F3 faults in No.1 structure of Nanpu Sag, and the results were compared with those from fault-reservoir displacement pressure differential methods without considering the diagenetic time and simple considering the diagenetic time. It is found that the results calculated by the integral mathematical-geological model are the closest to the actual underground situation, the errors between the hydrocarbon column height predicted by this method and the actual column height were 0–8 m only, proving that this model is more feasible and credible. 展开更多
关键词 lateral sealing of extensional fault integral mathematical–geological model diagenetic time diagenetic pressure Nanpu Sag
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A mechanically coupled MEMS filter with high-Q width extensional mode resonators 认领 引用 被引量：1
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作者 Wei Wang Wenli Liu +5 位作者 Junyuan Zhao Bo Niu Zeyu Wu Yinfang Zhu Jinling Yang Fuhua Yang 《Journal of Semiconductors》 EI CAS CSCD 2024年第8期41-48,共8页
This work presents a novel radio frequency(RF)narrowband Si micro-electro-mechanical systems(MEMS)filter based on capacitively transduced slotted width extensional mode(WEM)resonators.The flexibility of the plate lead... This work presents a novel radio frequency(RF)narrowband Si micro-electro-mechanical systems(MEMS)filter based on capacitively transduced slotted width extensional mode(WEM)resonators.The flexibility of the plate leads to multiple modes near the target frequency.The high Q-factor resonators of around 100000 enable narrow bandwidth filters with small size and simplified design.The 1-wavelength and 2-wavelength WEMs were first developed as a pair of coupled modes to form a passband.To reduce bandwidth,two plates are coupled with aλ-length coupling beam.The 79.69 MHz coupled plate filter(CPF)achieved a narrow bandwidth of 8.8 kHz,corresponding to a tiny 0.011%.The CPF exhibits an impressive 34.84 dB stopband rejection and 7.82 dB insertion loss with near-zero passband ripple.In summary,the RF MEMS filter presented in this work shows promising potential for application in RF transceiver front-ends. 展开更多
关键词 MEMS narrowband filter mechanically coupling quality factor width extensional mode
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Extensional Setting of Hainan Island in Mesoproterozoic:Evidence from Granitic Intrusions in the Baoban Group 认领 引用 被引量：1
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作者 LIU Yuheng MAO Jingwen +3 位作者 QIU Kunfeng HU Jun WANG Lei XU Deming 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2022年第4期1199-1212,共14页
The Mesoproterozoic Baoban Group is the oldest basement in Hainan Island and has played an important role in Columbia(Nuna)supercontinent reconstructions.The Mesoproterozoic granitic intrusions in the Baoban Group are... The Mesoproterozoic Baoban Group is the oldest basement in Hainan Island and has played an important role in Columbia(Nuna)supercontinent reconstructions.The Mesoproterozoic granitic intrusions in the Baoban Group are the most widely-exposed Precambrian magmatic rocks and are the key to understanding the tectonic settings of Hainan Island and its relationship with the South China Block and the Columbia supercontinent.New LA-ICP-MS zircon U-Pb dating on three mylonitic granite samples from the Tuwaishan and Baoban areas yield ages ranging from 1447 Ma to 1437 Ma,representing the absolute timing of the emplacement of the granitic intrusions.Combined with previously published geochronological data for rocks from the Baoban Group and regional mafic intrusions,it is concluded that the Baoban Group formed at 1460-1430 Ma,coeval with the emplacement of the granitic and mafic intrusions.New in-situ zircon LuHf isotope analyses for the three mylonitic granite samples yielded positiveε(t)values,ranging from+0.49 to+8.27,with model ages(T~C)ranging from 2181 Ma to 1687 Ma,suggesting that the granitic intrusions originated from a mixed source of Paleoproterozoic crust with juvenile crust.New zircon trace element data show characteristics of high Th/U values of 0.24-1.50,steep slopes from LREE to HREE and negative Pr,Eu anomalies with positive Ce,Sm anomalies,representing typical magmatic zircons formed in continental crust.Compared with available magmatic and detrital zircon ages from Precambrian rocks in the Cathaysia Block,Yangtze Block and western Laurentia,it is inferred that Hainan Island was separated from both the Cathaysia Block and the Yangtze Block,instead being connected with western Laurentia in the Columbia supercontinent.Considering the decreasing tendency of basin deposition time along the western margin of Laurentia,it is proposed that Hainan Island was located to the north or northwest of the Belt-Purcell Supergroup,along the western margin of Laurentia,during the breakup of the Columbia supercontinent. 展开更多
关键词 zircon U-Pb dating Lu-Hf isotopes granitic intrusions Baoban Group extensional setting Hainan Island
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Improved Geometric Model of Extensional Fault–bend Folding 认领 引用 被引量：1
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作者 ZHENG Xiaoli HE Guangyu +3 位作者 HU Senqing YAO Zewei WANG Hui LIN Lu 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2015年第6期1847-1857,共11页
Extensional fault-bend folds,also called rollovers,are one of the most common structures in extensional settings.Numerous studies have shown that oblique simple shear is the most appropriate mechanism for quantitative... Extensional fault-bend folds,also called rollovers,are one of the most common structures in extensional settings.Numerous studies have shown that oblique simple shear is the most appropriate mechanism for quantitative modeling of geometric relations between normal faults and the strata in their hanging walls.However,the oblique simple shear has a rather serious issue derived from the shear direction,particularly above convex bends.We use geometric and experimental methods to study the deformation of extensional fault-bend folds on convex bends.The results indicate that whether the fault bends are concave or convex,the shear direction of the hanging wall dips toward the main fault.On this basis,we improve the previous geometric model by changing the shear direction above the convex bends.To illustrate basin history,our model highlights the importance of the outer limit of folding instead of the growth axial.Moreover,we propose a new expression for the expansion index that is applicable to the condition of no deposition on the footwall.This model is validated by modeling a natural structure of the East China Sea Basin. 展开更多
关键词 extensional fault-bend folds shear direction expansion index outer limit of folding East China Sea Basin
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Spatio-temporal characteristics of acoustic emission during the deformation of rock samples with compressional and extensional en-echelon faults 认领 引用 被引量：3
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作者 蒋海昆 马胜利 +2 位作者 张流 侯海峰 曹文海 《Acta Seismologica Sinica(English Edition)》 2002年第4期402-413,共12页
The spatio-temporal characteristics of acoustic emission (AE) during the deformation of rock samples with compressional and extensional en-echelon faults have been studied. The results show that the pre-existing struc... The spatio-temporal characteristics of acoustic emission (AE) during the deformation of rock samples with compressional and extensional en-echelon faults have been studied. The results show that the pre-existing structure can significantly influence the patterns of AE spatial distribution. With increasing of differential stress, AE events firstly cluster around the two ends of pre-existing faults inside the jog and then along the line joining the two ends. The biggish AE events often occur around one end repeatedly. The image of AE clusters indicates the direction and the area of the fracture propagation. The direction of the macroscopic fracture in extensional and compressional jogs is perpendicular and parallel to the direction of axial stress, respectively. The weakening process before the fracturing of jog area is remarkable, and one of the typical precursors for the instability is that the cumulative frequency of AE events increases exponentially. After the fracturing of the jog the frequency and releasing strain energy of AE events decrease gradually. During the friction period, there is no precursory increasing of AE activity before the big stick-slip events. The change of b value in jog shows a typical change of decreasing tendentiously returning quickly before the instability. The decrease of b value occurs in the process of stress increasing and sometime goes down to the weakening stage, and the quick increase b values appears in a short time just before the instability. The comparative analysis shows that the difference in b value due to the different structures is larger than b value variation caused by increase of the differential stress. For the same sample, the temporal sequence of AE is strongly affected by the mechanical state, and the high loading velocity corresponds to the high release rate of strain energy and low b value. Due to its lower failure strength, the broken area is sensitive to small changes in differential stress. Therefore, it offers a potential explanation for the phenomena of precursory window or sensitive point and separation of seismic source and precursors. 展开更多
关键词 acoustic emission rock sample compressional en-echelon fault extensional en-echelon fault biaxial experiment differential stress
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The 144–140 Ma Mafic Dykes in North China and Northeast China Indicating Regional Extensional Tectonic Setting 认领 引用 被引量：1
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作者 XU Huan LIU Yongqing +1 位作者 KUANG Hongwei PENG Nan 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2017年第1期353-354,共2页
Objective Previous studies indicate that the North China Craton（NCC）had undergone the loss of thickened lithosphere and fundamental change of physical and chemical property of lithospheric mantle（the destruction of... Objective Previous studies indicate that the North China Craton（NCC）had undergone the loss of thickened lithosphere and fundamental change of physical and chemical property of lithospheric mantle（the destruction of NCC）during the Mesozoic.The peak period of the destruction of NCC is estimated to be 130 Ma,accompanied by widespread metamorphic core complex,rift basins,A-type granites and mafic dykes. However, it remains greatly controversial on the tectonic setting of NCC in the pre- 130Ma. 展开更多
关键词 NCC Ma Mafic Dykes in North China and Northeast China Indicating Regional Extensional Tectonic Setting The 144 SHRIMP
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Evolution of the Extensional Rifted Yunnan-Guizhou-Guangxi Oceanic Basin During the Late Hercynian to Middle Indosinian Stage 认领 引用 被引量：1
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作者 Xia Wenchen, Zhou Jie, Lei Jianxi, Zhang Nianmao and Peng YangChina U niversity of Geoscience, W uhan, Hubei Wang Yujun 《Acta Geologica Sinica(English Edition)》 SCIE CAS 1995年第4期341-357,共17页
On the basis of exhaustive researches on the facies sequences and depositlonal evolutionary process of various depositional systems, the genetic stratigraphic framework of the extensional rifted oceanic basin, which h... On the basis of exhaustive researches on the facies sequences and depositlonal evolutionary process of various depositional systems, the genetic stratigraphic framework of the extensional rifted oceanic basin, which has undergone strong structural destruction, has been reconstructed by means of dynamic genetic stratigraphic analysis. Five depositional episodes have been distinguished from various isochronous stratigraphic boundaries and stratigraphic sequences with the three-dimensional structure of each depositional episode analysed in detail. The tectonic paleogeographic environment corresponding to different stages of each depositional episode has been reconstructed for individual depositional system tracts. And the evolution history of this rifted basin has been divided into four stages' initial rifting and oceanization of continental crust, stretching and spreading of the basin, subduction and basin differentiation, and convergence and collision. A NNE-trending intracontinental soft collision suture was left after the closing of the basin. 展开更多
关键词 extensional rifted oceanic basin depositional system depositional system tract depositional episode genetic stratigraphic framework
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Twin Horsetailing Structures in the Extensional Regime based on Physical Experiment 认领 引用
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作者 LAO Haigang XU Hongyuan +3 位作者 WANG Yongshi MAO Cui Osman Salad HERSI LI Dianheng 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2024年第6期1649-1658,共10页
Horsetailing is an important feature to identify the strike-slip structure and indicates the movement mode of the fault.However,the formation mechanism of horsetailing in the extensional regime remains unclear.In this... Horsetailing is an important feature to identify the strike-slip structure and indicates the movement mode of the fault.However,the formation mechanism of horsetailing in the extensional regime remains unclear.In this study,the formation process of horsetailing is reproduced through physical experiment,simulating the Linnan sag in the extensional regime.The results of the physical experiment demonstrates that the formation of the horsetailing in the extensional regime requires two phases of non-coaxial stretching plus the segment of the principal fault.The stretching distance in the early phase is slightly smaller than that in the middle-late phase.The segment point of the principal fault is only the intersection of the horsetailing structure and the principal fault.The horsetailing formed in the extensional regime is different from that in the strike-slip regime.For the formation of structure,the principal fault is dip-slip in the early phase and then becomes an oblique-slip in the middle-late phase,and the horsetailing is composed of the middle-late new tensile faults.The fault properties of the horsetailing in the extensional regime has important guiding significance for the longitudinal fluid migration along the fault in petroliferous basins. 展开更多
关键词 fault segment extensional regime horsetailing non-coaxial stretching
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Temperature Effect on the Conformation Transition of Ultra-high Molecular Weight Polyethylene/Polypropylene Blends Undergoing Continuous Volume Extensional Flow:A Mesoscopic Simulation 认领 引用
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作者 WANG Junxia YAN Shilin YU Dingshan 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2022年第3期540-545,共6页
Due to the multiformity and complexity of chain conformation under external flow and the challenge of systematically investigating the transient conformation and dynamic evolution process of polymer chains at the mole... Due to the multiformity and complexity of chain conformation under external flow and the challenge of systematically investigating the transient conformation and dynamic evolution process of polymer chains at the molecular level by means of present experimental techniques,a universal description of both chain conformation and dynamics with respect to continuous volume extensional flow(CVEF)is still absent.Taking into account the temperature effect,we performed dissipative particle dynamics(DPD)simulations with the particles corresponding to the repeat units of polymers over a wide temperature range and analyzed the correlation with the conformational properties of ultra-high molecular weight polyethylene/polypropylene(UHMWPE/PP)blend in response to the CVEF.With time evolution,the polymer chains become highly oriented parallel to the flow direction instead of the initial random coiling and self-aggregation.It is found that a high temperature is necessary for more substantial compactness to take place than low temperature.The low-k plateau and low-k peak in structure factor S(k)curves suggest a low degree of conformational diversity and a high degree of chain stretching.It is also concluded that the intra-molecular C-C bond interaction is the main driving force for the dynamics process of the chain conformations undergoing CVEF,where the motion of the alkyl chains is seriously restricted owing to the increase in bond interaction potential,resulting in a reduction of the difference in diffusion rates among alkyl chains. 展开更多
关键词 temperature effect dissipative particle dynamics ultra-high molecular weight polyethylene polypropylene volume extensional flow chain conformation blends
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EFFECT OF INTERNAL VISCOSITY OF POLYMERIC FLUIDS UNDER STRONG EXTENSIONAL FLOWS 认领 引用
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作者 杨晓东 Roderick V.N.Melnik 《Chinese Journal of Polymer Science》 SCIE CAS 2009年第2期189-193,共5页
The dumbbell model with internal viscosity for a dilute polymer solution is investigated based on a balance of viscous drag and restoring Brownian forces.An approximate method is used to obtain the solution of extensi... The dumbbell model with internal viscosity for a dilute polymer solution is investigated based on a balance of viscous drag and restoring Brownian forces.An approximate method is used to obtain the solution of extensional stress in closed form in the case of steady flow.For different internal viscosities,this parametric study shows different asymptotic regimes of the extensional viscosity as a function of strain rate.This analysis may explain the attenuation of pressure drop in strong flows from a phenomeno... 展开更多
关键词 Polymeric fluid Internal viscosity Extensional viscosity.
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Investigation on Extensional Viscosity of Polymer Melts and Their Molecular Structures 认领 引用
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作者 柯勤飞 GotsisAlexandrosD. 《Journal of China Textile University(English Edition)》 1999年第4期9-12,共4页
The extensional viscosity of three polyethylenes(LDPE,LLDPE and HDPE)melts was measured in-uniaxialelongational flow at a constant extension rate,as well asby the process of fiber spinning"Rheotens"and the e... The extensional viscosity of three polyethylenes(LDPE,LLDPE and HDPE)melts was measured in-uniaxialelongational flow at a constant extension rate,as well asby the process of fiber spinning"Rheotens"and the entryflow methods.The melts showed the same melt flowingindex(MFI)but differed in their extensional viscositiesand attenuating forces,reflecting the differences in theirmolecular structures.The indirect methods could alsogive meaningful estimates for the extensional viscosity ofthe polymer melts,if the amount of the accumulated ex-tensional strain in each case was taken into consider-ation. 展开更多
关键词 extensional viscosity entry flow method rheo-tens polyethylene
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Asymmetric breakup of a droplet in an axisymmetric extensional flow 认领 引用 被引量：1
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作者 Dongming Yu Manman Zheng +1 位作者 Taoming Jin Jingtao Wang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2016年第1期63-70,共8页
The asymmetric breakups of a droplet in an axisymmetric cross-like microfluidic device are investigated by using a three-dimensional volume of fluid(VOF) multiphase numerical model. Two kinds of asymmetries(droplet lo... The asymmetric breakups of a droplet in an axisymmetric cross-like microfluidic device are investigated by using a three-dimensional volume of fluid(VOF) multiphase numerical model. Two kinds of asymmetries(droplet location deviation from the symmetric geometry center and different flow rates at two symmetric outlets) generate asymmetric flow fields near the droplet, which results in the asymmetric breakup of the latter. Four typical breakup regimes(no breakup, one-side breakup, retraction breakup and direct breakup) have been observed.Two regime maps are plotted to describe the transition from one regime to another for the two types of different asymmetries, respectively. A power law model, which is based on the three critical factors(the capillary number,the asymmetry of flow fields and the initial volume ratio), is employed to predict the volume ratio of the two unequal daughter droplets generated in the direct breakup. The influences of capillary numbers and the asymmetries have been studied systematically in this paper. The larger the asymmetry is, the bigger the oneside breakup zone is. The larger the capillary number is, the more possible the breakup is in the direct breakup zone. When the radius of the initial droplet is 20 μm, the critical capillary numbers are 0.122, 0.128, 0.145,0.165, 0.192 and 0.226 for flow asymmetry factor AS= 0.05, 0.1, 0.2, 0.3, 0.4 and 0.5, respectively, in the flow system whose asymmetry is generated by location deviations. In the flow system whose asymmetry is generated by two different flow rates at two outlets, the critical capillary numbers are 0.121, 0.133, 0.145, 0.156 and 0.167 for AS= 1/21, 3/23, 1/5, 7/27 and 9/29, respectively. 展开更多
关键词 Asymmetric breakup Droplet Volume of fluid method Axisymmetric extensional flow
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Post-Collisional Ductile Extensional Tectonic Framework in the UHP and HP Metamorphic Belts in the Dabie-Sulu Region, China 认领 引用 被引量：21
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作者 索书田 钟增球 +1 位作者 游振东 张泽明 《Acta Geologica Sinica(English Edition)》 SCIE CAS 2001年第2期151-160,共10页
The present-day observable tectonic framework of the ultrahigh-pressure (UHP) and high-pressure (HP) metamorphic belts in the Dabie-Sulu region was dominantly formed by an extensional process, mostly between 200 and 1... The present-day observable tectonic framework of the ultrahigh-pressure (UHP) and high-pressure (HP) metamorphic belts in the Dabie-Sulu region was dominantly formed by an extensional process, mostly between 200 and 170 Ma, following the Triassic collision between the Sino-Korean and Yangtze cratons. The framework that controls the present spatial distribution of UHP and HP metamorphic rocks in particular displays the typical features of a Cordilleran-type metamorphic core complex, in which at least four regional-scale, shallow-dipping detachment zones are recognized. Each of these detachment zones corresponds to a pressure gap of 0.5 to 2.0 GPa. The detachment zones separate the rocks exposed in the region into several petrotectonic units with different P-T conditions. The geometry and kinematics of both the detachment zones and the petrotectonic units show that the exhumation of UHP and HP metamorphic rocks in the Dabie-Sulu region was achieved, at least in part, by non-coaxial ductile flow in the multi-layered detachment zones, and by coaxial vertical shortening and horizontal stretching in the metamorphic units, under amphibolite- to greenschist-facies conditions, and in an extensional regime. All ductile extensional deformations occurred at depths below 10 to 15 km, i.e. below the brittle/ductile deformation transition. 展开更多
关键词 Dabie-Sulu region UHP-HP metamorphic belt ductile extension detachment zone exhumation
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