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Nondestructive testing method based on lamb waves for localization and extent of damage

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Acta Mechanica Solida Sinica 2017年第1期30卷 65-74页

作者： jianlin chen Zheng Li Kezhuang Gong State Key Laboratory of Turbulence and Complex System College of EngineeringPeking University

Based on Lamb wave analysis of propagation in plate-like structures, a damage detection method is proposed that not only locates the position of the damage accurately but also estimates its size. Similar damage detection methods focus only on localization giving no quantitative estimation of extent. To improve detection, we propose two predictive circle methods for size estimation. Numerical simulations and experiments were performed for an aluminum plate with a hole. Two PZT configurations of different sizes were designed to excite and detect Lamb waves. From cross-correlation analysis, the damage location and extent can be determined. Results show that the proposed method enables a better quantitative resolution in detection, the size of the inspection area influences the accuracy of damage identification, and the closer is the inspected area to the damage, the more accurate are the results. The method proposed can be developed into a multiple-step detection method for multi-scale analysis with prospective accuracy.

关键词： Lamb wave Damage detection Cross correlation PZT wafer Aluminum plate

Chronological and Geochemical Study of the Cenozoic Potassic Felsic Igneous Rocks in Western Yunnan,SE Tibet:Implications for their Tectonic Mechanisms

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Acta Geologica Sinica(English Edition) 2022年第3期96卷 904-918页

作者： TANG Wanli chen jianlin TAN Rongyu State Key Laboratory of Isotope Geochemistry Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100083China CAS Center for Excellence in Deep Earth Science Guangzhou 510640China

Whether there is a relationship between widespread Cenozoic igneous rocks and the activated Ailao Shan-Red River shear zone(ASRR)in western Yunnan,SE Tibet,remains highly *** geochronological,and geochemical data derived from Cenozoic igneous rocks both within and far from the ASRR offers *** these coeval felsic rocks(36.9-33.5 Ma)are enriched in large-ion lithophile elements relative to high field strength elements,they also display some special geochemical features,such as high Y and Yb values of syenitic porphyries,which contrast with the high Sr and low Y contents of monzoporphyries and granitic *** syenitic porphyries exhibit geochemical characteristics similar to those of coeval mafic magmas,e.g.,high K 2 O,Y,and Yb contents,indicating that the former were probably generated by fractional crystallization of the ***,the high Sr/Y(56.1-109)monzoporphyries and granitic porphyries,combined with their low MgO,and Cr(or Ni)contents,suggest that they were mainly derived from partial melting of a thickened mafic lower *** that these Cenozoic magmatic events exhibiting planar distributions occurred outside of the activation of the ASRR(31-20 Ma),then they were not controlled by the ***,they were tied to convective removal of a thickened lower lithospheric mantle in western Yunnan during the Paleogene.

关键词： geochronology geochemistry igneous rocks Cenozoic Ailao Shan-Red River shear zone Yunnan Province

Geochemistry of the Eocene Felsic Porphyric Rocks and High-Mg Potassic Rocks along JARSZ:Implication for the Tectonic Evolution in Eastern Tibet

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Acta Geologica Sinica(English Edition) 2010年第6期84卷 1448-1460页

作者： chen jianlin XU Jifeng WANG Baodi KANG Zhiqiang Key Laboratory oflsotope Geochronology and Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China chengdu Institute of Geology and Mineral Resources Chengdu 610081 China Guilin University of Technology Guilin 541004 China

Eocene felsic porphyric rocks and the high-Mg potassic volcanic rocks（HMPR） occur along the Jinshajiang-Ailao Shan-Red River shear zone（JARSZ） in eastern *** with the HMPR,which are generally believed to be sourced from an enriched mantle,the felsic porphyric rocks show similar K_2O contents,enrichment in LREE and LILE,particularly radiogenic isotope（*** and Nd） features much similar to the former,implying generation of the felsic porphyric rocks most likely related to the HMPR,although they both have clearly different major and trace element compositions. The close relationship in spatial-temporal distribution and similar Sr-Nd characteristics between the felsic porphyric rocks and HMPR in eastern Tibet indicate that both of them were possibly formed by a similar tectonic process（event）.Combining the basic dikes in southern and eastern Tibet,we suggest that the break-off of north-dipping Neo-Tethyan slab in southern Tibet during 50-40 Ma,triggered formation of high-Mg potassic *** led to developing felsic porphyric magma production by partial melting of underplating HMPR in the lower crust,or fractionation crystallization of the high-Mg potassic *** break-off of slab in the Eocene may also have contributed to the abundant ore-forming material related to earlier subduction events,resulting in formation of the porphyric deposits along JARSZ in eastern Tibet.

关键词： Eocene felsic porphyric rocks HMPR break-off eastern Tibet

Freshwater snail and shrimp differentially affect water turbidity and benthic primary producers

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Water Biology and Security 2022年第1期1卷 34-40页

作者： Yulun Guo Peiyu Zhang jianlin chen Jun Xu Institute of Hydrobiology Chinese Academy of SciencesWuhanChina Liaoning Key Laboratory of Aquatic Biology College of Fisheries and Life ScienceDalian Ocean UniversityDalian116000China The Guangxi Key Laboratory of Theory and Technology for Environmental Pollution Control College of Environmental Science and EngineeringGuilin University of TechnologyGuilin541004China

Benthic macroinvertebrates play key roles in shallow aquatic ecosystems and can contribute substantially to aquatic food ***,how macroinvertebrates with different behaviors(for example,pertaining to locomotion,foraging and burrowing)impact water quality and primary producers has not been fully ***,we performed two consecutive microcosm experiments to test the effects of(1)macroinvertebrates with different behaviors(a low mobility scraper aquatic snail Bellamya aeruginosa and a high mobility shredder freshwater shrimp Macrobrachium nipponense)and(2)different shrimp biomasses on water clarity and the composition of benthic primary *** results showed that presence of snails significantly increased the biomass of filamentous green algae and decreased the biomass of *** contrast,presence of shrimp significantly decreased the biomass of filamentous green algae and increased the biomass of periphyton,and these effects were biomass *** green algae disappeared when shrimp biomass reached 9.8 g m^(-2).No interactive effects of snail and shrimp presence were *** could be attributed to different food preferences by the two consumers,with snails preferring periphyton(mainly diatoms)and shrimp preferring filamentous green *** presence of snails decreased water turbidity,while shrimp increased water turbidity,which showed a hump-shaped response to shrimp biomass with a peak at 24.2 g m^(-2).These results are likely because the snail is a low mobility grazer and can filter suspended particles,while the shrimp is a high mobility shredder with burrows,which can strongly disturb *** decrease in water disturbance at high shrimp biomass might be due to food limitation,thus reducing burrowing and foraging *** snail nor shrimp affected the biomass of ***,while the biomass of *** increased with shrimp *** reason for this could be that shrimp increased nutrient availabili

关键词： Aquatic plant Zoobenthos Filamentous algae Macroinvertebrate Macrophyte Periphyton Trophic interaction Water turbidity

Chronology and Geochemistry of the Nadingcuo Volcanic Rocks in the Southern Qiangtang Region of the Tibetan Plateau:Partial Melting of Remnant Ocean Crust along the Bangong-Nujiang Suture

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Acta Geologica Sinica(English Edition) 2010年第6期84卷 1461-1473页

作者： WANG Baodi chen jianlin XU Jifeng WANG Liquan ZENG Qinggao DONG Yanhui chengdu Institute of Geology and Mineral Resources Chengdu 610081 China Key Laboratory of Geochronology and Geochemistry Guanzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China Regional Geological Surveying Party of the Tibet Bureau of Geology and Exploration Lhasa 851400 China The Second Institute ofOceangraphy SOA Hangzhou 310012 China

The Nadingcuo high-K calc-alkaline rocks mainly composed of trachyte and trachyandesite are the largest outcrop area of volcanic rocks in southern Qiangtang terrane in the Tibetan plateau. However,their exact source and peterogenesis are still debated.^（40）Ar-^（39）Ar and LAM-ICPMS zircon U-Pb isotopic dating confirm that these rocks erupted in *** addition,the Nadingcuo volcanic rocks are characterized by high Sr/Y content ratios,similar with the adakite derived from partial melting of oceanic *** can be further classified as high Mg~#（Mg~#=48-57） and low Mg~# （Mg~#=33-42） *** Nadingcuo adakitic rocks have relatively low（^（87）Sr/^（86）Sr）_i and highε_（Nd）（t）, showing a trend of similarity to the Dongcuo ophiolite present in the Bangong-Nujiang oceanic crust. Simple modeling indicates that the Nadingcuo adakitic rocks are a mix resulting from the basalt of Bangong-Nujiang Ocean with 10%-20%crustal material of Lhasa *** these bases we suggest that the low Mg~# Nadingcuo adakitic rocks are the product of partial melting of remnant oceanic crust with small sediment,and the high Mg~# rocks are the result of reaction between rising melt of remnant oceanic crust with subducted sediment and mantle ***,the origin of Nadingcuo adakitic rocks may be related to intracontinental subduction triggered by collision of India-Asia during Cenozoic.

关键词： intracontinental subduction adakitic rocks remnant oceanic crust Nadingcuo Qiangtang Tibetan plateau

New index of ferromanganese crusts reflecting oceanic environmental oxidation

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Science China Earth Sciences 2007年第3期50卷 371-384页

作者： WU GuangHai ZHOU HuaiYang ZHANG HaiSheng LING HongFei MA WeiLin ZHAO HongQiao chen jianlin LIU JieHong Key Laboratory of Marine Ecosystem&Biogeochemistry of State Oceanic Administration Hangzhou 310012China Key Laboratory of Submarine Geoscience of State Oceanic Administration Hangzhou 310012China Geochemistry Institute of Guangzhou Chinese Academy of SciencesGuangzhou 510640China State Key Laboratory for Mineral Deposit Research Nanjing UniversityNanjing 210093China

Ferromanganese crusts (hereinafter crusts) form in aerobic environment and the environmental oxida-tion degree is recorded by the redox sensitive element Co in the crusts. The ages of the layers from the surface to bottom of the crusts are determined, and main element contents at high resolution along the depth sections of three crusts from the Pacific Ocean are analyzed by an electron microprobe. Thus the variations of Co/(Fe+Mn) and Co/(Ni+Cu) with age/depth of the crust layers are obtained. By comparing the ratios of Co/(Fe+Mn) and Co/(Ni+Cu) with the δ 18O curves of the Pacific benthic foraminifera, we find that these two ratios can reflect the variation of the environmental oxidation state under which the crust layers deposit. The evolution of the oxidation degree reflected by the two indexes resembles the evo-lution of temperature since the Oligocene reflected by the δ 18O curves of the Pacific benthic foraminif-era. This suggests that the crust-forming environment after the Oligocene is controlled mainly by the oxygen-rich bottom water originated from the Antarctic bottom water (AABW). However it is not the case prior to the Oligocene. Furthermore it suggests that the environmental oxidation degree controls the formation of the crusts and the Co contents in the crusts. This explains why the Co contents in the crusts increase with time up to now.

关键词： ferromanganese crusts the Pacific Ocean oxidation degree of environment the Oligocene AABW

In vivo inducing collagen regeneration of biodegradable polymer microspheres

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Regenerative Biomaterials 2021年第5期8卷 95-107页

作者： Yixin Zhang Hanwen Liang Qian Luo jianlin chen Nan Zhao Wenxia Gao Yuji Pu Bin He Jing Xie School of Smart Health Chongqing College of Electronic EngineeringChongqing 401331China School of Laboratory Medicine Sichuan Provincial Engineering Laboratory for Prevention and Control Technology of Veterinary Drug Residue in Animal-origin FoodChengdu Medical CollegeChengdu 610500China Puliyan(Nanjing)Medical Science&Technology Co.LTD Nanjing 211500China College of Chemistry and Materials Engineering Wenzhou UniversityWenzhou 325027China National Engineering Research Center for Biomaterials Sichuan UniversityChengdu 610064China Department of Stomatology The First Affiliated Hospital of Wenzhou Medical UniversityWenzhou 325000China

Biodegradable polymer particles have been used as dermal fillers for pre-clinical and clinical *** impact of material properties of polymers is very important to develop products for aesthetic medicine such as dermal ***,eight biodegradable polymers with different molecular weights,chemical compositions or hydrophilic-hydrophobic properties were prepared and characterized for systematical study for aesthetic medicine *** microspheres with 20-100 lmwere *** in vitro degradation study showed that poly(L-lactic-co-glycolic acid)75/25 microspheres degraded the fastest,whereas poly(L-lactic acid)(PLLA)microspheres with intrinsic viscosity of 6.89([g]¼6.89)with the highest molecular weight showed the slowest degradation *** these microspheres were fabricated dermal fillers according to the formula of SculptraVR,they were injected subcutaneously into the back skin of *** vivo results demonstrated that the degradation rate of microspheres strongly correlated with the foreign body reaction and collagen regeneration was induced by *** microspheres with faster degradation rate induced inflammatory response and the collagen regeneration maintained in shorter ***([g]¼3.80)microsphere with a moderate molecular weight and degradation rate could strongly regenerate Type I and III collagen to maintain a long-term aesthetic medicine *** properties of size,morphology and degradation behavior would influence the foreign body reaction and collagen regeneration.

关键词： biodegradable polymers microspheres collagen regeneration dermal fillers

Factors Affecting Chinese Raters' Rating of High-Stakes English Exam Essays

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Chinese Journal of Applied Linguistics 2017年第2期40卷 208-228,230页

作者： chen jianlin Lanzhou Universit

This study consists of two questionnaire surveys conducted in two stages to investigate factors that high-stakes exam essay raters believe to affect their rating behavior. Raters were all university Chinese teachers of English majors. Seventy-three participants in stage one and 75 in stage two responded to the same questionnaire. Both exploratory factor analysis and confirmatory factor analysis were used in data analysis. Results showed that there were generally six broad factors interfering with the rating process： rating scale, rater training, rating supervision, rater characteristics, eye-catching text features and rating condition. The interaction of those factors reflected the tension between the constraints executed by the test institution and raters＇ own knowledge and understanding of essay rating. This study may shed light on measures taken to improve essay rating quality.

关键词： raters TEM-8 rating process rater behavior

Post-90s college students party member must go beyond the five sense

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International Journal of Technology Management 2013年第8期 10-12页

作者： Gang chen jianlin Wang Liang Ge Southwest Petroleum University ChengduSichuan 610500 China

Currently, colleges and universities, Post-90s college students has gradually become the main force of college students party, how to play their constructive role as a college party workers is a problem in front of us. To solve this problem, we propose effective measures must be taken to enable them to overcome some of the wrong ideology, such as student centered consciousness, making nice consciousness, Abandon rights, abandon obligations consciousness, party members community spirit is not vested in the party organization, the sense of thought like good learning is more important than good thought consciousness, so as to guide the Post-90s college students to actively join the party building.

关键词： Post-90s college students Party member building Membership awareness