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Metamorphic evolution of the East Tethys tectonic domain and its tectonic implications

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Science China Earth Sciences 2023年第12期66卷 2686-2711页

作者： qiangqiang zhang Xiaoying GAO Renxu CHEN Yongfei ZHENG School of Earth and Space Sciences Universiy of Science and Technology of ChinaHefei 230026China Key Laboraiory of Crust-Mantle Materials and Environments Chinese Academy of SciencesHefei 230026China Center of Excellence for Comparative Planetology Chinese Academy of Sciences Hefei 230026China

The China Central Orogenic System(CCOS),extending in an east-west direction in the middle part of China,is composed of the Early Paleozoic Altyn-North Qilian-North Qaidam-East Kunlun-North Qinling-North Tongbai orogens in the west and the Late Paleozoic to Early Mesozoic South Tongbai-Hong'an-Dabie-Sulu orogens in the *** were produced by oceanic subduction and continental subduction/collision during the closure of the Proto-Tethys and the Paleo-Tethys oceans,*** types of metamorphic rocks with various ages are extensively exposed in these orogens,and they were produced at different geothermal gradients in different stages during the tectonic evolution of convergent continental margins,making them ideal targets to reconstruct the spatiotemporal evolution of the Eastern Tethys tectonic *** this article,an integrated study of metamorphic temperature(T)-pressure(P)-time(t)records is presented for metamorphic rocks along the CCOS,aiming to ascertain the change of metamorphic T/P ratios in both time and space,and then shed light on the tectonic evolution of the East Tethys tectonic domain in association with the thermal state change of convergent continental *** results indicate that despite the difference in metamorphic ages,metamorphic rocks in different orogens show a common trend with clockwise P-T-t *** respect to plate convergence for subduction and collision,regional metamorphism is categorized into three stages:(1)an early convergent stage,corresponding to low T/P Alpine-type blueschist-to eclogite-facies high-P to ultrahigh-P metamorphism;(2)a later convergent stage,corresponding to the medium T/P Barrovian-type medium-P amphibolite to high-P granulite-facies metamorphism;and(3)a post-convergent stage,corresponding to the high T/P Buchan-type lowP amphibolite to MP granulite-facies ***,a few metamorphic rocks only record a two-sage metamorphic evolution,with an early Barrovian-type high-P granuli

关键词： Tethys tectonics Oceanic closure Crustal metamorphism Geothermal gradient Intracontinental rifting

Experimental Study on Melting Process in an Industrial Level Molten Salt Tank

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Journal of Thermal Science 2020年第2期29卷 457-463页

作者： LI Zhi zhang qiangqiang WANG Zhifeng LI Jun Key Laboratory of Solar Thermal Energy and Photovoltaic System of Chinese Academy of Sciences Beijing 100190China Institute of Electrical Engineering Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Beijing Engineering Research Center of Solar Thermal Power Beijing 100190China

Thermal energy storage(TES) is an important part of concentrating solar power(CSP) plants. The primary advantage of TES in CSP plants is the ability to dispatch electrical output to match peak demand periods and reduce the levelized cost of electricity. The major challenge of the molten salt is its high freezing point, leading to additional complicating freeze protection. This paper presents the experimental results of melting process of a mixed nitrate salt with a melting temperature of 115℃ in a 20 m^3 industrial level tank. Twenty electrical heaters inside the tank are used to heat the salt with a total maximum input power of 240 kW. In order to ensure a safe and fast melting process, the whole process adopted an operating strategy of combining automatic control with manual control. The whole melting process lasted for 314 hours. The salt temperature showed the greatest increase in the first 38 hours. Finally, an economic operation mode of molten salt heat storage tank was obtained.

关键词： molten salt melting concentrating solar power thermal energy storage

Optical pulse repetition rate multiplication based on series-coupled double-ring resonator

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Photonics Research 2016年第2期4卷 61-64页

作者： Xiaowei Dong Mengzhen Xu qiangqiang zhang College of Information Engineering North China University of Technology

In this paper, optical pulse repetition rate multiplication based on a series-coupled double-ring resonator is proposed. First, the spectral characteristic of the series-coupled double-ring resonator is simulated and the optimum coupling coefficients to achieve a periodic flat-top passband are obtained. Then, high-quality pulse repetition rate multiplication is realized by periodically filtering out spectral lines of the input pulse train. Different multiplication factors N 2, 3, 4, 5 can be obtained by adjusting the ring radii. In addition, compared with a single-ring resonator, the multiplied output pulse train by a series-coupled double-ring resonator exhibits much better power uniformity.

关键词： ring rate

Vision-based multi-level synthetical evaluation of seismic damage for RC structural components: a multi-task learning approach

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Earthquake Engineering and Engineering Vibration 2023年第1期22卷 69-85页

作者： Xu Yang Qiao Weidong Zhao Jin zhang qiangqiang Li Hui Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of Industry and InformationTechnology Harbin Institute of TechnologyHarbin 150090China Key Lab of Structures Dynamics Behavior and Control of the Ministry of Education Harbin Institute of TechnologyHarbin 150090China School of Civil Engineering Harbin Institute of TechnologyHarbin 150090China School of Civil Engineering and Mechanics Lanzhou UniversityLanzhou 730000China

Recent studies for computer vision and deep learning-based,post-earthquake inspections on RC structures mainly perform well for specific tasks,while the trained models must be fine-tuned and re-trained when facing new tasks and datasets,which is inevitably *** study proposes a multi-task learning approach that simultaneously accomplishes the semantic segmentation of seven-type structural components,three-type seismic damage,and four-type deterioration *** proposed method contains a CNN-based encoder-decoder backbone subnetwork with skip-connection modules and a multi-head,task-specific recognition *** backbone subnetwork is designed to extract multi-level features of post-earthquake RC *** multi-head,task-specific recognition subnetwork consists of three individual self-attention pipelines,each of which utilizes extracted multi-level features from the backbone network as a mutual guidance for the individual segmentation task.A synthetical loss function is designed with real-time adaptive coefficients to balance multi-task losses and focus on the most unstably fluctuating *** experiments and comparative studies are further conducted to demonstrate their effectiveness and *** results show that the proposed method can simultaneously recognize different structural components,seismic damage,and deterioration states,and that the overall performance of the three-task learning models gains general improvement when compared to all single-task and dual-task models.

关键词： post-earthquake evaluation multi-task learning computer vision structural component segmentation seismic damage recognition deterioration state assessment

Three-dimensional meta-architecture with programmable mechanical properties

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International Journal of Smart and Nano Materials 2022年第1期13卷 152-165,I0009页

作者： qiangqiang zhang Jiaqi Dong Yantang Zhao and Yueyan Zheng Key Laboratory of Mechanics on Disaster and Environment in Western China(Lanzhou University) The Ministry of Education of ChinaLanzhou730000P.R.China College of Civil Engineering and Mechanics Lanzhou UniversityLanzhou730000P.R.China

Artificial metamaterials have attracted widespread attention of research communities due to their anomalous physical properties compared to those of conventional *** this study,we designed a three-dimensional(3D)lightweight metaarchitecture consisting of 6-connected anti-chiral *** mechanical properties(***’s modulus,compression strength,and Poisson’s ratio)of the proposed meta-architecture could be programmed by adjusting a series of geometric parameters,as shown through numerical ***,an optically sensitive polymer-based 3D meta-architecture with 6-connected anti-chiral features was constructed by the stereolithography *** to the regulation of the negative Poisson’s ratio,3D meta-architecture achieved a greater ductility under compression than those of traditional truss structures while retaining a relatively high strength and low *** experiments validated the excellent tunability of the mechanical properties of the proposed 3D 6-connected antichiral *** results suggest the promising applications of this structure in lightweight aircraft,vibration isolation,and mechanical sensors.

关键词： Artificial metamaterials anomalous physical properties anti-chiral features ductile compressibility tunability on mechanical properties

Highly strengthening and toughening biomimetic ceramic structures fabricated via a novel coaxially printing

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Journal of Advanced Ceramics 2024年第4期13卷 403-412页

作者： Kunkun Song Shengda Yang Ningqi Shao Yantang Zhao Peng He Yongfeng Wei Hengzhong Fan Yongsheng zhang qiangqiang zhang State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China School of Civil Engineering and Mechanics Lanzhou UniversityLanzhou 730000China Key Laboratory of Mechanics on Disaster and Environment in Western China(Lanzhou University) Ministry of EducationLanzhou 730000.China

Additive manufacturing technology,by manipulating and emulating inherent multiscale,multi-material,and multifunctional structures found in nature,has created new opportunities for constructing heterogeneous structures associated with special properties and achieving ultra-high mechanical performance and reliability in ceramic composite *** this study,we have developed an innovative fabrication method designated as coaxial 3D printing for the synchronous construction of two constituents into ceramic composites with a tooth enamel biomimetic ***,the stiff silicate and flexible epoxy served as a strengthening bridge and toughening layer,*** method differed from the traditional approach of randomly dispersing reinforcing components within a ceramic *** allowed for the direct creation of an internally effective three-dimensional reinforcement network structure in ceramic *** process facilitated synergistic deformation and simultaneous enhancement of multiple materials and hierarchical *** to the uniform distribution of internal stress and effective block of microcrack propagation,the biomimetically structured silicate/epoxy ceramic composite has demonstrated much significant enhancement in mechanical properties,includingcompressive strength(48.8±3.12MPa),flexuralstrength(10.39±1.23MPa),andflexuraltoughness(218.7±54.6kJ/m^(3)),which was 0.5,2.1,and 47.5 times as high as those of the intrinsic brittle silicate ceramics,***-situ characterization and multiscale finite element simulation of microstructural evolution during three-point bending deformation further validated multiple-step features of the fracture process(silicate bridge fracture,interface detachment,epoxy extraction,and rupture),which benefited from interpenetrating structural features achieved by coaxial printing to accomplish with the complex propagating routines of the crack deflection in silicate ceramic *** coaxia

关键词： coaxial 3D printing silicate ceramic composites enamel biomimetic microstructure strengthening bridge tougheninglayer crackdeflection

How variable progenitor clones construct a largely invariant neocortex

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National Science Review 2024年第1期11卷 129-144页

作者： Zhongfu Shen Jiajun Yang qiangqiang zhang Kuiyu Wang Xiaohui Lv Xiaolin Hu Jian Ma Song-Hai Shi New Cornerstone Science Laboratory IDG/McG overn Institute for Brain Research Tsinghua-Peking Center for Life Sciences Beijing Frontier Research Center for Biological Structure School of Life Sciences Tsinghua University Department of Computer Sciences Tsinghua University College of Life Sciences Nankai University Chinese Institute for Brain Research

The neocortex contains a vast collection of diverse neurons organized into distinct layers. While nearly all neocortical neurons are generated by radial glial progenitors(RGPs), it remains largely unclear how a complex yet organized neocortex is constructed reliably and robustly. Here, we show that the division behavior and neuronal output of RGPs are highly constrained with patterned variabilities to support the reliable and robust construction of the mouse neocortex. The neurogenic process of RGPs can be well-approximated by a consistent Poisson-like process unfolding over time, producing deep to superficial layer neurons progressively. The exact neuronal outputs regarding layer occupation are variable; yet, this variability is constrained systematically to support all layer formation, largely reflecting the variable intermediate progenitor generation and RGP neurogenic entry and exit timing differences. Together, these results define the fundamental features of neocortical neurogenesis with a balanced reliability and variability for the construction of the complex neocortex.

关键词： neocortex radial glial progenitor intermediate progenitor neurogenesis clonal variability layer formation

Novel Approach for Improved Tribological Behavior of Biodiesel Soot in Liquid Paraffin

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China Petroleum Processing & Petrochemical Technology 2019年第1期21卷 101-109页

作者： Li Chuan Song Hui zhang Jun Wu Bo zhang qiangqiang Zhuang Yuan Hu Xianguo School of Mechanical Engineering Hefei University of Technology School of Automobile and Transportation Engineering Hefei University of Technology

To improve the tribological behavior of biodiesel soot(BDS) in liquid paraffin(LP), the order of biodiesel soot was increased through thermally oxidized treatment at 500 ℃, and the oil solubility was then improved through a modification using oleylamine(OLA). The BDS and thermally oxidized oleylamine-modified BDS(T-BDS-OLA)were characterized through various methods including the use of TG, FETEM, Raman spectroscopy, FTIR, and a zeta potentiometer. The tribological properties and mechanisms of the BDS before and after the thermally oxidized treatment modification were investigated using a ball-on-disc reciprocating tribometer, FESEM, 3 D laser-scanning microscopy, and Raman spectroscopy. The results showed that T-BDS-OLA has a higher degree of order than the BDS, with an onion-like microstructure. BDS and T-BDS-OLA can both improve the antifriction and antiwear properties of LP at a soot content of 0.1%-0.4%, while T-BDS-OLA in LP shows better antifriction and antiwear properties than BDS. The tribological mechanisms can be attributed to both types of soot acting as spacing and roll bearing between the friction surfaces. In addition, the exfoliated graphitic sheets from T-BDS-OLA can form a carbon lubrication layer providing easy sliding.

关键词： biodiesel soot liquid paraffin antifriction and antiwear carbon onion

Preparation,Dispersion and Tribological Properties of Oleophilic Lanthanum Hydroxide/Graphene Oxide Nanocomposites

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China Petroleum Processing & Petrochemical Technology 2020年第2期22卷 111-121页

作者： Wu Bo zhang qiangqiang Song Hui Yang Bingxun Tian Ming Hu Xianguo School of Mechanical Engineering Hefei University of TechnologyHefei 230009

Lanthanum hydroxide/graphene oxide nanocomposites(La(OH)3/GO)modified by octadecylamine(OCA),oleylamine(OLA),and polyvinylpyrrolidone(PVP)were prepared,respectively,as the base oil *** dispersion stability of different modified La(OH)3/GO in base oil was studied by means of *** tribological properties of oleophilic La(OH)3/GO in base oil were investigated using an UMT ball-disc *** micro-morphology and chemical composition of the worn surface were characterized by 3 D laser microscope,SEM,EDS,XPS,and Raman spectroscopy,*** wettability performance of the worn surface was also studied based on the contact angle *** test results showed that the OLA-La(OH)3/GO nanocomposites had good dispersion stability in base *** anti-wear performance of base oil was improved significantly by the addition of OLA-La(OH)3/GO *** characterizations of worn surface showed that the OLA-La(OH)3/GO nanocomposites could form the metal oxide and graphene protective films effectively on the friction interface and thus increased the oil wettability of the worn surface,thereby resulting in an improved wear resistance.

关键词： oleophilic modification La(OH)3/GO nanocomposites dispersion stability tribological property