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Geochemical characteristics and geological significance of Cretaceous phonotephrite from the Mid-Pacific Mountains

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Science China Earth Sciences 2018年第6期61卷 745-764页

作者： Shuangshuang CHEN jiaqi liu Key Laboratory of Cenozoic Geology and Environment Institute of Geology and Geophysics Chinese Academy of Sciences State Key Laboratory of Lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences Institutions of Earth Science Chinese Academy of Sciences

Systematic analyses were conducted including the petrographic features, major and trace elements, Sr and Nd isotopic compositions, and mineral structure and compositions of whole rocks. Mid-Pacific Mountain volcanic rocks are mainly phonotephrite with a porphyritic texture. Phenocrysts are mainly composed of Ca-rich plagioclase, clinopyroxene and *** volcanic rocks are significantly rich in large-ion lithophile and light rare earth elements, without obvious Eu anomalies(δEu=0.99–1.03), and with relatively enriched^(87) Sr/^(86) Sr(0.703829–0.704313) and^(143) Nd/^(144) Nd isotopic ratios(0.512857–0.512871), suggesting that they have similar but more enriched features than the OIB magmatic source. These volcanic rocks may originate from relatively deep magma source with the existence of spinel-garnet Iherzolites, and have undergone partial melting at a low degree of 1–3%. In addition, The residual Nb-Ta minerals(such as sphene, rutile, perovskite) may remain in the mantle source, and the magma components have undergone metasomatism by carbonate melt/fluid or alkali-rich fluid, causing high contents of incompatible elements and significant loss of Nb, Ta and Ti in these volcanic rocks. There are many similarities between the phonotephrites in the Mid-Pacific Mountain and the volcanic rocks in the Line Islands based on the tectonic settings and the geochemical characteristics. We thus speculate that Site 313 volcanic rocks in the Mid-Pacific Mountain is most likely to be a continuation of the Line Islands.

关键词： Phonotephrite OIB-type mantle source Carbonatite metasomatism Line Islands Mid-Pacific Mountain

A survey on network node ranking algorithms:Representative methods,extensions,and applications

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Science China(Technological Sciences) 2021年第3期64卷 451-461页

作者： liu jiaqi LI XueRong DONG JiChang School of Economics and Management University of Chinese Academy of SciencesBeijing 100190China Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China

The ranking of network node importance is one of the most essential problems in the field of network *** ranking algorithms serve as an essential part in many application scenarios such as search engine,social networks,and recommendation *** paper presents a systematic review on three representative methods:node ranking based on centralities,Page Rank algorithm,and HITS ***,we investigate the latest extensions and improvements of these representative methods,provided with several main application *** by the survey of current literature,we attempt to propose promising directions for future *** conclusions of this paper are enlightening and beneficial to both the academic and industrial communities.

关键词： complex networks node ranking methods Page Rank HITS algorithms

U-series dating on late Quaternary sediments from Balikun Lake

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Chinese Science Bulletin 1998年第17期43卷 1434-1441页

作者： jiaqi liu Zhibang Ma Chinese Acad Sci Inst Geol Beijing 100029 Peoples R China

The U-series component-dating method has been employed to date the sediment core B-194 from Balikun Lake. 230Th/ 232Th and 234U/ 232Th ratios in various components of the samples dissolved in different concentration acids were measured respectively. The results indicate that there is a good relationship of the isotopic ratios between the solutions and the residues, and that uranium and thorium isotopic fractionations did not occur during acid leaching. Based on the U-series ages obtained by using component-dating method, a 144-ka time sequence was established corresponding to the upper 25-m interval of the B-194 core, which is in agreement with palaeomagnetic dating results. The fact that the palaeoclimatic and palaeoenvironmental record labeled with U-series ages is correlative with the deep-sea δ 18O SPECMAP also demonstrates that the U-series component-dating method can be used to date lake sediments.

关键词： Balikun Lake sediments component-dating model U-series age.

Numerical investigation of dynamic stall suppression of rotor airfoil via improved co-flow jet

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Chinese Journal of Aeronautics 2022年第3期35卷 169-184页

作者： jiaqi liu Rongqian CHEN Yancheng YOU Zheyu SHI School of Aerospace Engineering Xiamen UniversityXiamen 361005China Rotor Aerodynamics Key Laboratory China Aerodynamics Research and Development CenterMianyang 621000China

The decrease in aerodynamic performance caused by the shock-induced dynamic stall of an advancing blade and the dynamic stall of a retreating blade at low speed and high angles of attack limits the flight speed of a ***,little research has been carried on the flow control methods employed to suppress both the dynamic stall induced by a shock wave and the dynamic stall occurring at high angles of *** dynamic stall suppression of a rotor airfoil by Co-Flow Jet(CFJ)is numerically investigated in this *** flowfield of the airfoil is simulated by solving Reynolds Averaged Navier-Stokes equations based on the sliding mesh ***,to improve the effect of a traditional CFJ on suppressing rotor airfoil shock-induced dynamic stall,an improved CFJ—a CFJ-sloping slot is *** shows that the CFJsloping slot suppresses the shock-induced dynamic stall more effectively than a traditional ***,the improved CFJ can also suppress the dynamic stall of rotor airfoil at low speed and high angles of *** improved CFJ proposed in this paper is an effective flow control method that simultaneously suppresses the dynamic stall of the advancing and retreating *** mechanism of the improved CFJ in suppressing the dynamic stall of the rotor airfoil is studied,and a comparison is made between the improved CFJ and the traditional CFJ in terms of dynamic stall suppression at high and low ***,the effect of improved CFJ parameters(the jet momentum coefficient,the position of the injection/suction slot,and the size of the injection/suction slot)on shock-induced dynamic stall suppression is analyzed.

关键词： Co-flow jet Dynamic stall Flow control Parameter analysis Rotor airfoil

Nature and evolution of the lithospheric mantle revealed by water contents and He-Ar isotopes of peridotite xenoliths from Changbaishan and Longgang basalts in Northeast China

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Science Bulletin 2019年第18期64卷 1325-1335页

作者： Qinghu Xu jiaqi liu Huaiyu He Yunhui Zhang Key Laboratory of Cenozoic Geology and Environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049.China College of Earth Sciences Chinese Academy of SciencesBeijing 100029China Key Laboratory of Earth and Planetary Physics.Institute of Geology and Geophysics Chinese Academy of SciencesBeijing 100029China State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu 610059China

The nature and evolution of the lithospheric mantle underlying Northeast(NE)China were investigated by assessing the mineral chemistry,water contents,and noble gas(He-Ar)isotopes of peridotite xenoliths captured by Cenozoic basalts from the Changbaishan and Longgang *** xenoliths,which have863–1141℃ equilibration temperatures,primarily comprise spinel lherzolites and rare spinel *** Mg#(Fo)values of olivine in the peridotite xenoliths vary from 86.9 to *** clinopyroxenes have high Ti/Eu and low(La/Yb)N,and their chondrite-normalized rare earth elements(REEs)exhibit light REE-depletion to-enrichment patterns,indicating that the mantle underneath the investigated region was predominantly subjected to partial melting(1%–10%)and was metasomatized by silicate *** measured3He/4He ratios of the Changbaishan xenoliths have a narrow range from 5.8 Ra to 8.4 Ra with an average of 7.4 ***3He/4He isotopic ratios of the Longgang xenoliths varied from 4.7 Ra to8.1 Ra with an average of 5.9 Ra;slightly lower than the Changbaishan *** whole-rock H2Ocontents of the studied peridotite ranged from 9 to 132 *** high H2O contents in excess of50 ppm(up to 132 ppm)might represent newly accreted and cooled asthenospheric materials,while those with H2O contents lower than 50 ppm(as little as 9 ppm)may represent thinned,relic,ancient lithospheric *** geochemical evidences,in combination with published data,indicated that the lithospheric mantle beneath the Changbaishan and Longgang in NE China is dominated by the younger and more fertile lithospheric mantle with a minor ancient and refractory *** addition,the lithospheric mantle of this area was metasomatized by melts related to the recent subduction event(e.g.,Pacific oceanic plate).Therefore,the westward-dipping Pacific oceanic plate subduction had an important contribution to the transformation of the lithospheric mantle beneath NE China.

关键词： Subcontinental lithospheric mantle Peridotite xenoliths Mineral chemistry He-Ar isotopes Water contents Northeast China

Features of major greenhouse gases in loess,Shanxi Province,China

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Chinese Science Bulletin 2001年第17期46卷 1469-1472页

作者： Qiang liu jiaqi liu Shuzhen Sui Chinese Acad Sci Inst Geol & Geophys Beijing 100029 Peoples R China

According to the investigations of five loess sections in Shanri Province, China, it was found that the concentrations of the major greenhouse gases CO2, CH4 and N2O in loess-paleosol sequences are generally high, even sometimes may be several times or scores of tunes higher than their atmospheric concentrations respectively. Although the CO2 concentration in the same loess section shows poor regularity among different layers, it increases slowly from north to south in space. The CH4 concentration in the layers under Malan Loess is much higher than that in the atmosphere, although it is not high in Malan Loess. Most of the δ13C values of CO2 in loess are -11.14‰-15.48‰, (relative to PDB standard). Analysis of carbon isotopic compositions of CO2 indicates that the main source of CO2 in loess section is decomposition of ’stable’ organic matters by microbes. The δ13Cg of CO2 is a little heavier than organic source for exchanging carbon isotope with carbonate in loess. The abundant carbonate in loess

关键词： loess-paleosol sequence major greenhouse gases concentration δ13Cg value deuterogenic carbonate carbon reservoir.

Effect of Miocene basaltic volcanism in Shanwang (Shandong Province, China) on environmental changes

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Science China Earth Sciences 2007年第12期50卷 1823-1827页

作者： GUO ZhengFu liu jiaqi CHEN XiaoYu Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China

Miocene(16―10 Ma) basalts,together with significantly well-preserved fossils(including animal and plant fossils) in the contemporaneously tephra-rich Maar sediments,are located in Shanwang volcanic region,Shandong Province,*** area of the basaltic eruption products is about 240 *** field observations indicate that most of basaltic rocks are fissure eruptive products and some are central eruptives constrained by linear *** well-preserved fossils in the lacustrine deposits have been considered to be a result of mass *** on physically volcanologic modeling results,eruption column of the basaltic fissure activities in the Shanwang volcanic region is estimated to have entered the *** observations indicate that the basalts have porphyritic textures with phenocrysts of olivine,pyroxene,plagioclase feldspar and alkali feldspar setting in groundmass of plagioclase feldspar,alkali feldspar,quartz,apatite and *** on observations of tephra,tuff and tuffites collected in the Maar sediments of the Shanwang area,we determined major element oxide concentrations and volatile composition of melt inclusions in phenocrysts and matrix glasses by electron microprobe ***(including S,Cl,F and H2O) concentrations erupted into the stratosphere were estimated by comparing pre-and post-eruptive volatile *** determination results show that contents of S,Cl,F and H2O emitted into the stratosphere were 0.18%― 0.24%,0.03%―0.05%,0.03%―0.05% and 0.4%―0.6%,respectively,which was characterized by high-S contents *** of volatiles emitted in the Shanwang volcanic region are much higher than those in eruptions which had a substantial effect on climate and *** to the com-positions and amounts of the volatiles erupted from the Miocene basaltic volcanism in Shanwang,we propose a hypothesis that volatile-rich basaltic volcanism could result in the mass mortalities by in-jectin

关键词： volcanic volatiles, paleo-environment, acid rain, basalt, Shanwang

Discrimination of two kinds of sedimentary laminae in maar lakes of China

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Chinese Science Bulletin 2000年第24期45卷 2292-2295页

作者： Guoqiang Chu jiaqi liu Dongsheng liu Chinese Acad Sci Inst Geol & Geophys Beijing 100029 Peoples R China

Varved lacustrine sediments have been found from high latitude to low latitude, even in tropical area. Paleoenvironmental and paleoclimatic research has increasingly relied on the use of varved sediments to provide high-resolution geochronologies and climatic reconstructions. However, a special depositional environment is necessary for varve formation and preservation. Generally, varves can be found in the sediments of maar lakes because of their special geological and hydrological environment. The preliminary research showed that a few carbonate laminations are developed in the Huguangyan maar lake, south China. They are poorly developed and not annual laminations, and may be related to periodically drought. Diatomaceous laminations are found in the maar lakes in northeast China. Diatomaceous laminations with cyclic nature corresponding with seasonal diatom blooming are the credible natural clock.

关键词： maar lake carbonate lamination diatomaceous lamination.

An Ultra-Compact Broadband Polarizing Beam Splitter Utilizing Hybrid Plasmonic Waveguide

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China Communications 2023年第6期20卷 49-59页

作者： Li Zhang jiaqi liu Can Pan Yatao Yang College of Electronics and Information Engineering Shenzhen UniversityShenzhen 518000China

Polarizing beam splitter has rather significant applications in polarization diversity circuits and polarization multiplexing *** this paper,we present an asymmetric polarizing beam splitter utilizing hybrid plasmonic *** special hybrid structure with a hybrid waveguide and a dielectric waveguide can limit the energy of TE and TM modes to a different ***,we can achieve beam splitting by adjusting the corresponding parameters of the two ***,we studied the influences of different structure parameters on the real part of the effective mode refractive index of the two waveguides,and obtained a set of parameters that satisfy the condition of strong coupling of TM mode and weak coupling of TE ***,the performance of our proposed polarizing beam splitter is evaluated *** length of the coupling section is only 4.1μm,and the propagation loss of TM and TE modes is 0.0025 d B/μm and 0.0031 d B/μm ***,the extinction ratios of TM and TE modes are 10.62 d B and 12.55 d B,***,the proposed device has excellent wavelength *** the entire C-band,the fluctuation of the whole normalized output power is less than *** short,our proposed asymmetric polarizing beam splitter features ultra-compactness,low propagation loss,and broad bandwidth,which would provide promising applications in polarization multiplexing system and polarization diversity circuits relevant to optical interconnection.

关键词： polarizing beam splitter hybrid plasmonic waveguide directional coupler polarization multiplexing systems